





















                              [1mGNUPLOT[0m
                  [1mAn Interactive Plotting Program[0m


                   [4mThomas[24m [4mWilliams[24m [4m&[24m [4mColin[24m [4mKelley[0m
            [4mVersion[24m [4m4.1[24m [4morganized[24m [4mby:[24m [4mHans-Bernhard[24m [4mBroeker[0m
                [4mMajor[24m [4mcontributors[24m [4m(alphabetic[24m [4morder):[0m
                        [4mHans-Bernhard[24m [4mBroeker[0m
                            [4mJohn[24m [4mCampbell[0m
                          [4mRobert[24m [4mCunningham[0m
                            [4mDavid[24m [4mDenholm[0m
                            [4mGershon[24m [4mElber[0m
                            [4mRoger[24m [4mFearick[0m
                           [4mCarsten[24m [4mGrammes[0m
                              [4mLucas[24m [4mHart[0m
                             [4mLars[24m [4mHecking[0m
                            [4mThomas[24m [4mKoenig[0m
                              [4mDavid[24m [4mKotz[0m
                             [4mEd[24m [4mKubaitis[0m
                             [4mRussell[24m [4mLang[0m
                          [4mAlexander[24m [4mLehmann[0m
                            [4mAlexander[24m [4mMai[0m
                            [4mEthan[24m [4mMerritt[0m
                             [4mPetr[24m [4mMikulik[0m
                            [4mCarsten[24m [4mSteger[0m
                              [4mTom[24m [4mTkacik[0m
                          [4mJos[24m [4mVan[24m [4mder[24m [4mWoude[0m
                               [4mAlex[24m [4mWoo[0m
                          [4mJames[24m [4mR.[24m [4mVan[24m [4mZandt[0m
                           [4mJohannes[24m [4mZellner[0m
  [4mCopyright[24m [4m(C)[24m [4m1986[24m [4m-[24m [4m1993,[24m [4m1998,[24m [4m2004[24m   [4mThomas[24m [4mWilliams,[24m [4mColin[24m [4mKelley[0m
     Mailing list for comments: gnuplot-info@lists.sourceforge.net
   Mailing list for bug reports: gnuplot-bugs@lists.sourceforge.net
                           13 August 2007




















                                 -2-








             This manual was prepared by Dick Crawford.
                          3 December 1998





























































[1m1.  Gnuplot[0m





[1m2.  Copyright[0m


    Copyright (C) 1986 - 1993, 1998, 2004, 2007  Thomas Williams,
Colin Kelley

Permission to use, copy, and distribute this software and its docu-
mentation for any purpose with or without fee is hereby granted,
provided that the above copyright notice appear in all copies and
that both that copyright notice and this permission notice appear in
supporting documentation.

Permission to modify the software is granted, but not the right to
distribute the complete modified source code.  Modifications are to
be distributed as patches to the released version.  Permission to
distribute binaries produced by compiling modified sources is
granted, provided you
  1. distribute the corresponding source modifications from the
   released version in the form of a patch file along with the bina-
ries,
  2. add special version identification to distinguish your version
   in addition to the base release version number,
  3. provide your name and address as the primary contact for the
   support of your modified version, and
  4. retain our contact information in regard to use of the base
   software.
Permission to distribute the released version of the source code
along with corresponding source modifications in the form of a patch
file is granted with same provisions 2 through 4 for binary distri-
butions.

This software is provided "as is" without express or implied war-
ranty to the extent permitted by applicable law.


      AUTHORS

      Original Software:










GNUPLOT 4.1                                                        2


         Thomas Williams,  Colin Kelley.

      Gnuplot 2.0 additions:
         Russell Lang, Dave Kotz, John Campbell.

      Gnuplot 3.0 additions:
         Gershon Elber and many others.

      Gnuplot 4.0 additions:
         See list of contributors at head of this document.



[1m3.  Introduction[0m


[1mgnuplot [22mis a command-driven interactive function and data plotting
program.  It is case sensitive (commands and function names written
in lowercase are not the same as those written in CAPS).  All com-
mand names may be abbreviated as long as the abbreviation is not
ambiguous.  Any number of commands may appear on a line (with the
exception that [1mload [22mor [1mcall [22mmust be the final command), separated by
semicolons (;).  Strings are indicated with quotes.  They may be
either single or double quotation marks, e.g.,

      load "filename"
      cd 'dir'

although there are some subtle differences (see [1msyntax [22mfor more
details).

Any command-line arguments are assumed to be names of files contain-
ing [1mgnuplot [22mcommands, with the exception of standard X11 arguments,
which are processed first.  Each file is loaded with the [1mload [22mcom-
mand, in the order specified.  [1mgnuplot [22mexits after the last file is
processed.  When no load files are named, [1mgnuplot [22menters into an
interactive mode.  The special filename "-" is used to denote stan-
dard input.  See help for [1mbatch/interactive [22mfor more details.

Many [1mgnuplot [22mcommands have multiple options. Version 4 is less sen-
sitive to the order of these options than earlier versions, but some
order-dependence remains. If you see error messages about unrecog-
nized options, please try again using the exact order listed in the
documentation.

Commands may extend over several input lines by ending each line but
the last with a backslash (\).  The backslash must be the _last_
character on each line.  The effect is as if the backslash and new-
line were not there.  That is, no white space is implied, nor is a
comment terminated.  Therefore, commenting out a continued line com-
ments out the entire command (see [1mcomments[22m).  But note that if an
error occurs somewhere on a multi-line command, the parser may not
be able to locate precisely where the error is and in that case will










GNUPLOT 4.1                                                        3


not necessarily point to the correct line.

In this document, curly braces ({}) denote optional arguments and a
vertical bar (|) separates mutually exclusive choices.  [1mgnuplot [22mkey-
words or [1mhelp [22mtopics are indicated by backquotes or [1mboldface [22m(where
available).  Angle brackets (<>) are used to mark replaceable
tokens.  In many cases, a default value of the token will be taken
for optional arguments if the token is omitted, but these cases are
not always denoted with braces around the angle brackets.

For on-line help on any topic, type [1mhelp [22mfollowed by the name of the
topic or just [1mhelp [22mor [1m? [22mto get a menu of available topics.

The new [1mgnuplot [22muser should begin by reading about [1mplotting [22m(if on-
line, type [1mhelp plotting[22m).

See the simple.dem demo, also available together with other demos on
the web page
          http://www.gnuplot.info/demo/simple.html



[1m4.  Seeking-assistance[0m


There is a mailing list for [1mgnuplot [22musers.  Note, however, that the
newsgroup
      comp.graphics.apps.gnuplot
is identical to the mailing list (they both carry the same set of
messages).  We prefer that you read the messages through the news-
group rather than subscribing to the mailing list.  Instructions for
subscribing to gnuplot mailing lists may be found via the gnuplot
development website on SourceForge
          http://sourceforge.net/projects/gnuplot

The address for mailing to list members is:
      gnuplot-info@lists.sourceforge.net

Bug reports and code contributions should be mailed to:
      gnuplot-bugs@lists.sourceforge.net

The list of those interested in beta-test versions is:
      gnuplot-beta@lists.sourceforge.net

There is also the canonical (if occasionally out-of-date) gnuplot
web page at

          http://www.gnuplot.info

Before seeking help, please check the

          FAQ (Frequently Asked Questions) list.











GNUPLOT 4.1                                                        4


When posting a question, please include full details of the version
of [1mgnuplot[22m, the machine, and operating system you are using.  A
_small_ script demonstrating the problem may be useful.  Function
plots are preferable to datafile plots.  If email-ing to gnuplot-
info, please state whether or not you are subscribed to the list, so
that users who use news will know to email a reply to you.  There is
a form for such postings on the WWW site.




[1m5.  New features introduced in version 4.2[0m


Gnuplot version 4.2 offers many new features introduced since the
preceding official version 4.0. This section lists major additions
and gives a partial list of changes and minor new features. For a
more exhaustive list, see the NEWS file.





     [1m5.1.  New plot styles[0m







          [1m5.1.1.  Histogram[0m


          Histograms, or bar charts, can be produced.  See [1mhis-[0m
          [1mtograms[22m.




          [1m5.1.2.  Label plots[0m


          In coordination with the new [1mdatastrings [22mfeature described
          below, gnuplot can draw a label at each vertex of a curve.
          See [1mlabels[22m.

















GNUPLOT 4.1                                                        5


          [1m5.1.3.  Image data[0m


          The [1mimage [22mand [1mrgbimage [22mstyles allow to plot 2D images
          (from ascii or [1mbinary [22mfiles) and map them in a 2D or 3D
          plot.  See [1mimage [22mand [1mrgbimage[22m.




          [1m5.1.4.  Filled curves[0m


          The plot style [1mfillstyle [22mhas been augmented to allow to
          fill the area between two input curves with a color or a
          pattern.  See [1mfilledcurves[22m.




          [1m5.1.5.  Vectors[0m


          Gnuplot can draw plots with vectors with a small arrow-
          head, requiring four or six columns of data for 2D or 3D,
          respectively.  See [1mvectors[22m.




     [1m5.2.  Input from binary data files[0m


     Gnuplot can now read a generic [1mbinary [22minput, including matrix
     binary and [1mgeneral binary [22m(until now gnuplot supported only its
     own [1mbinary matrix [22mformat). Several matrix file formats are
     autodetected ([1mgpbin[22m, [1medf[22m, [1mavs[22m).  Binary data files are mainly
     useful for [1mimage [22mand [1mrgbimage [22mdrawings.  See [1mbinary [22mand [1mbinary[0m
     [1mgeneral filetype[22m.




     [1m5.3.  New plot elements[0m



















GNUPLOT 4.1                                                        6


          [1m5.3.1.  RGB colors[0m


          Explicit RGB colors can be specified for all plot elements
          instead of specifying a predefined linetype.  See [1mcolor-[0m
          [1mspec[22m.




          [1m5.3.2.  Arbitrary rectangles[0m


          You can place rectangles with desired fill style and bor-
          der anywhere in a 2D plot.  See [1mset object rectangle[22m.




     [1m5.4.  String handling[0m






          [1m5.4.1.  String and text data read from datafiles[0m


          Gnuplot can now read and process text fields in datafiles.
          See [1mdatastrings[22m.



          [1m5.4.2.  User-defined string variables, operators, and[0m
          [1mfunctions[0m


          String variables and string functions are introduced. Most
          gnuplot commands that previously required a string con-
          stant will now also accept a string variable, a string
          expression, or a function that returns a string.  See
          [1mstring variables[22m.




     [1m5.5.  Macros[0m


     Gnuplot supports command line macro expansion  by '@stringvari-
     ablename'.  See [1mmacros[22m.











GNUPLOT 4.1                                                        7


     [1m5.6.  Auto-layout of multiple plots on a page[0m


     The [1mmultiplot [22mmode is now able to layout automatically simple
     multiplots without having to set the size or the position for
     each plot.  See [1mmultiplot[22m.




     [1m5.7.  Internal variables[0m


     Gnuplot now exports several "read-only" variables such as
     GPVAL_TERM, GPVAL_X_MIN, etc.  See [1mgnuplot-defined variables[22m.




     [1m5.8.  New or revised terminal drivers[0m






          [1m5.8.1.  `wxt`[0m


          The [1mwxt [22mterminal is an interactive and cross-platform ter-
          minal for on-screen rendering. It uses the wxWidgets
          library for its user interface, and Cairo associated with
          Pango for the actual rendering, providing nice plots with
          antialiasing on lines and text. The terminal supports the
          full range of gnuplot capabilities, including mousing,
          pm3d plots, image plots and enhanced text.



          [1m5.8.2.  `emf`[0m


          The [1memf [22mterminal generates an Enhanced Metafile Format
          file. This file format is the metafile standard on MS
          Win32 Systems.



          [1m5.8.3.  `gif`, `jpeg`, `png`[0m


          The code for the terminals using the [1mgd [22mlibrary has been
          consolidated.  The [1mgif [22mterminal also knows how to produce










GNUPLOT 4.1                                                        8


          an animated gif from a sequence of plots.



          [1m5.8.4.  `postscript`[0m


          The [1mpostscript [22mterminal can load prologue files, which can
          contain additional user-defined sections with, for exam-
          ple, character encodings.  See [1mpostscript prologue[22m.



          [1m5.8.5.  `ai`[0m


          The Adobe Illustrator [1mai [22mdriver is outdated. Since Adobe
          Illustrator understands PostScript files, [1mset terminal[0m
          [1mpost level1 ... [22mshould be used instead.



          [1m5.8.6.  `epslatex`, `pslatex`, `pstex`[0m


          The terminals supporting an output to latex augmented by
          PostScript commands have been consolidated. Many options
          are the same as in the [1mpostscript [22mterminal.



          [1m5.8.7.  `windows`[0m


          The [1mwindows [22mterminal now supports the [1menhanced text [22mmode.




     [1m5.9.  Canvas size[0m



     In earlier versions of gnuplot, some terminal types (but not
     all) used the values from [1mset size [22mto control also the size of
     the output canvas.  This behaviour is now deprecated.  In
     future versions of gnuplot the options 'set size' and 'set term
     <foo> size' will have complementary effects:

     [1mset term <terminal_type> size <XX>, <YY> [22mcontrols the size of
     the output file, or "canvas". Please see individual terminal
     documentation for allowed values of the size parameters.  By
     default, the plot will fill this canvas.










GNUPLOT 4.1                                                        9


     [1mset size <XX>, <YY> [22mscales the plot itself relative to the size
     of the canvas.  Scale values less than 1 will cause the plot to
     not fill the entire canvas.  Scale values larger than 1 will
     cause only a portion of the plot to fit on the canvas.  Please
     be aware that setting scale values larger than 1 may cause
     problems on some terminal types.

     Example:

           set term pbm size 600, 400
           set size 0.5, 0.5
           set output "figure.pbm"
           plot "data" with lines

     These commands will produce an output file "figure.pbm" that is
     600 pixels wide and 400 pixels tall. The plot will fill the
     lower left quarter of this canvas.  This is consistent with the
     way multiplot mode has always worked, however it is a change in
     the way some drivers worked for single plots in version 4.0.

     Most terminal drivers in 4.2 follow the new convention. However
     the behaviour of the png/jpeg/gif driver is under the control
     of a configuration option.  See [1mbackwards compatibility[22m.




[1m6.  Backwards compatibility[0m


Gnuplot version 4.0 deprecated certain syntax used in earlier ver-
sions, but continued to recognize it.  Version 4.2 also accepts the
deprecated syntax by default, but this is now under the control of a
configuration option, and can be disabled as follows:

      ./configure --disable-backwards-compatibility

Notice: Deprecated syntax items may be disabled permanently in
future versions.

One major difference is the introduction of required keywords to
disambiguate complicated commands. A notable issue was the use of
bare numbers to specify offsets, line and point types.  Illustrative
examples:

Deprecated:
      set data linespoints
      plot <foo> 2 4
New:
      set style data linespoints
      plot <foo> linetype 2 pointtype 4

Another major compatibility issue is the interaction of the commands










GNUPLOT 4.1                                                       10


[1mset size [22mand [1mset term <foo> size[22m.  In earlier versions of gnuplot
the behaviour of various terminal types with respect to [1mset size [22mwas
very inconsistent.  In the future, all terminals will behave the
same way.

In version 4.2 most terminals follow the new convention ([1mset size[0m
has no effect on the output canvas size). However, the png/gif/jpeg
terminal still follows the older, deprecated behaviour unless you
have configured with [1m--disable-backwards-compatibility[22m.  In the next
version of gnuplot all terminal types will follow the new conven-
tion. You are strongly advised not to use [1mset size [22mto control the
size in pixels of png/gif/jpeg output files.  Instead use [1mset term[0m
[1mpng size <XX>,<YY>[22m.

Please see [1mset size[22m, [1mset term size [22mand the documentation for indi-
vidual terminals.




[1m7.  Features introduced in version 4.0[0m


Gnuplot version 4.0 contained many features introduced since the
preceding official version 3.7.  These are summarized here.





     [1m7.1.  Mouse and hotkey support in interactive terminals[0m



     Interaction with the current plot via mouse and hotkeys is sup-
     ported for the X11, OS/2 Presentation Manager, ggi, Windows,
     and wxWidgets terminals. See [1mmouse input [22mfor more information
     on mousing. See help for [1mbind [22mfor information on hotkeys. Also
     see the documentation for individual mousing terminals [1mggi[22m, [1mpm[22m,
     [1mwindows[22m, [1mwxt [22mand [1mx11[22m.

     Sample script: mousevariables.dem




     [1m7.2.  New terminals[0m



     [1maqua[22m: New terminal for Mac OS X. Requires AquaTerm 1.0 or
     later.











GNUPLOT 4.1                                                       11


     [1mepslatex[22m: New terminal. Prepares eps figures for inclusion in
     LaTeX documents.

     [1mgif[22m: Consolidated with png/jpeg terminals. Requires libgd.

     [1mggi[22m: New full-screen interactive terminal for Linux. Interface
     to the General Graphics Interface Library.

     [1mpdf[22m: New terminal exporting Adobe Portable Document Format.
     Requires libpdf.

     [1mpng [22mand [1mjpeg[22m: Support for GIF, PNG and JPEG image output is
     provided by a new driver via libgd. The new driver supports
     many more features than the old png driver, including TrueType
     fonts. Requires libgd.

     [1msvg[22m: New terminal exporting Scalable Vector Graphics.




     [1m7.3.  New plot style `pm3d`[0m



     The [1msplot [22mcommand is now capable of plotting 2D maps and 3D
     surfaces colored by greyscale or color palettes. See help for
     [1mset pm3d[22m, [1mset palette[22m, [1mset cbrange[22m, [1mset view map[22m, [1mset colorbox[0m
     and [1mtest palette[22m.

     Sample scripts: pm3d.dem pm3dcolors.dem pm3dgamma.dem




     [1m7.4.  Filled boxes[0m



     A solid color or patterned fill style can be set for any plot
     style that contains boxes. See [1mboxes[22m, [1mboxerrorbars[22m, [1mboxxyerror-[0m
     [1mbars[22m, [1mcandlesticks[22m, [1mset style fill[22m.

     Sample scripts: fillstyle.dem candlesticks.dem




     [1m7.5.  New plot option smooth frequency[0m



     Input data can be filtered through several built-in routines










GNUPLOT 4.1                                                       12


     for interpolation or approximation of data.  See [1msmooth[22m, [1mfre-[0m
     [1mquency[22m, [1munique[22m.

     Sample scripts: step.dem mgr.dem




     [1m7.6.  Improved text options[0m



     Most gnuplot plot commands that produce text labels now accept
     modifiers to specify text color, font, size, and rotation
     angle. See [1mset label[22m.  Not all terminal types support these
     options, however.  The enhanced text mode previously available
     for the postscript and pm terminals has been extended to other
     terminal types as well.  Terminal types currently supported
     include aqua, dumb, jpeg, pdf, pm, png, postscript, x11, win-
     dows, and wxt.  See [1menhanced text[22m.

     Sample scripts: textcolor.dem textrotate.dem




     [1m7.7.  More text encodings[0m



     Several terminals, including [1mpostscript[22m, [1mx11 [22mand [1mpm[22m, support
     additional text [1mencodings[22m: ISO 8859-1 (Latin 1), ISO 8859-2
     (Latin 2), ISO 8859-15 (variant of 8859-1 with Euro sign),
     KOI8-R and KOI8-U (cyrillic), and miscellaneous codepages. See
     [1mencoding [22mfor more details.




     [1m7.8.  Arrows[0m



     Single- or double-ended arrows can be placed on a plot individ-
     ually from the command line or from a data file via the [1mplot[0m
     [1mwith vectors [22mstyle.  See [1mset style arrow[22m, [1mplotting styles vec-[0m
     [1mtors[22m.

     Sample scripts: arrowstyle.dem vector.dem














GNUPLOT 4.1                                                       13


     [1m7.9.  Data file format[0m



     The new [1mset datafile [22mcommand can be used to specify information
     about the format of input data files, including the characters
     used to separate fields, to indicate comment lines, and to
     specify missing data.  Gnuplot now attempts to recognize text
     fields with embedded blanks as single entities based on the
     datafile format settings.  This allows input from csv (comma-
     separated value) files such as those exported by spreadsheet
     programs. See [1mset datafile[22m.  See also the [1mbinary [22moption (intro-
     duced in 4.2).




     [1m7.10.  New commands[0m



     [1mset view map [22mselects a top-view 2D projection of 3D surface
     plot.

     [1mset term push [22mand [1mset term pop [22msave and restore the current
     terminal type.

     [1mload [22mand [1msave [22mcommands accept piped input and output, respec-
     tively.




     [1m7.11.  Other changes and additions[0m



     Since gnuplot 4.0, [1munset <something> [22mis preferred to [1mset[0m
     [1mno<something>[22m.  The older form has been deprecated.  Version
     4.2 continues to allow the older syntax, but such backwards
     compatibility may be lost in future versions.

     Commands of the form [1mset <something> <style> [22malso are depre-
     cated in favor of the more general form [1mset style <something>[0m
     [1m<options>[22m.  Many more plot elements now have style options of
     their own, including arrows, filled areas, lines, and points.
     There are also style settings for input data and formatting.
     Please see [1mset style[22m, [1mset decimalsign[22m, and [1mset datafile[22m.

     The MS Windows package includes an additional executable [1mpgnu-[0m
     [1mplot.exe [22mto support piping command through standard input,
     which is otherwise not available for graphical applications on
     this system.










GNUPLOT 4.1                                                       14


     [1m7.12.  Accompanying documentation[0m



     In directory docs/psdocs/ you may find new information in the
     gnuplot output postscript file guide, list of postscript sym-
     bols in different encodings.

     Improved FAQ. Please read it before asking your question in a
     public forum.

     There are plenty of new demos *.dem in the demo/ directory.
     Please run them, for example by
           load "all.dem"
     before asking for help.  Plots produced by the demo scripts can
     also be viewed at http://www.gnuplot.info/demo/




[1m8.  Batch/Interactive Operation[0m


[1mgnuplot [22mmay be executed in either batch or interactive modes, and
the two may even be mixed together on many systems.

Any command-line arguments are assumed to be names of files contain-
ing [1mgnuplot [22mcommands (with the exception of standard X11 arguments,
which are processed first).  Each file is loaded with the [1mload [22mcom-
mand, in the order specified.  [1mgnuplot [22mexits after the last file is
processed.  When no load files are named, [1mgnuplot [22menters into an
interactive mode.  The special filename "-" is used to denote stan-
dard input.

Both the [1mexit [22mand [1mquit [22mcommands terminate the current command file
and [1mload [22mthe next one, until all have been processed.

Examples:

To launch an interactive session:
      gnuplot

To launch a batch session using two command files "input1" and
"input2":
      gnuplot input1 input2

To launch an interactive session after an initialization file
"header" and followed by another command file "trailer":
      gnuplot header - trailer














GNUPLOT 4.1                                                       15


[1m9.  Command-line-editing[0m


Command-line editing is supported by the Unix, Atari, VMS, MS-DOS
and OS/2 versions of [1mgnuplot[22m.  Also, a history mechanism allows pre-
vious commands to be edited and re-executed.  After the command line
has been edited, a newline or carriage return will enter the entire
line without regard to where the cursor is positioned.

(The readline function in [1mgnuplot [22mis not the same as the readline
used in GNU Bash and GNU Emacs.  If the GNU version is desired, it
may be selected instead of the [1mgnuplot [22mversion at compile time.)


The editing commands are as follows:




   +-------------------------------------------------------------+
   |Character   Function                                         |
   +-------------------------------------------------------------+
   |            Line Editing                                     |
   |   ^B       move back a single character.                    |
   |   ^F       move forward a single character.                 |
   |   ^A       move to the beginning of the line.               |
   |   ^E       move to the end of the line.                     |
   | ^H, DEL    delete the previous character.                   |
   |   ^D       delete the current character.                    |
   |   ^K       delete from current position to the end of line. |
   | ^L, ^R     redraw line in case it gets trashed.             |
   |   ^U       delete the entire line.                          |
   |   ^W       delete from the current word to the end of line. |
   +-------------------------------------------------------------+
   |            History                                          |
   |   ^P       move back through history.                       |
   |   ^N       move forward through history.                    |
   +-------------------------------------------------------------+



On the IBM PC, the use of a TSR program such as DOSEDIT or CED may
be desired for line editing.  The default makefile assumes that this
is the case;  by default [1mgnuplot [22mwill be compiled with no line-edit-
ing capability.  If you want to use [1mgnuplot[22m's line editing, set
READLINE in the makefile and add readline.obj to the link file.  The
following arrow keys may be used on the IBM PC and Atari versions if
readline is used:















GNUPLOT 4.1                                                       16


                  +-------------------------------+
                  |   Arrow key       Function    |
                  +-------------------------------+
                  |   Left Arrow      same as ^B. |
                  |  Right Arrow      same as ^F. |
                  |Ctrl Left Arrow    same as ^A. |
                  |Ctrl Right Arrow   same as ^E. |
                  |    Up Arrow       same as ^P. |
                  |   Down Arrow      same as ^N. |
                  +-------------------------------+
                  +-------------------------------+



The Atari version of readline defines some additional key aliases:




                  +------------------------------+
                  |   Key      Function          |
                  +------------------------------+
                  |  Undo      same as ^L.       |
                  |  Home      same as ^A.       |
                  |Ctrl Home   same as ^E.       |
                  |   Esc      same as ^U.       |
                  |  Help      help plus return. |
                  |Ctrl Help   help .            |
                  +------------------------------+
                  +------------------------------+





[1m10.  Comments[0m


Comments are supported as follows: a [1m# [22mmay appear in most places in
a line and [1mgnuplot [22mwill ignore the rest of the line.  It will not
have this effect inside quotes, inside numbers (including complex
numbers), inside command substitutions, etc.  In short, it works
anywhere it makes sense to work.

See also [1mset datafile commentschars [22mfor specifying comment charac-
ters in data files.



[1m11.  Coordinates[0m













GNUPLOT 4.1                                                       17


The commands [1mset arrow[22m, [1mset key[22m, [1mset label [22mand [1mset object [22mallow you
to draw something at an arbitrary position on the graph.  This posi-
tion is specified by the syntax:

      {<system>} <x>, {<system>} <y> {,{<system>} <z>}

Each <system> can either be [1mfirst[22m, [1msecond[22m, [1mgraph[22m, [1mscreen[22m, or [1mcharac-[0m
[1mter[22m.

[1mfirst [22mplaces the x, y, or z coordinate in the system defined by the
left and bottom axes; [1msecond [22mplaces it in the system defined by the
second axes (top and right); [1mgraph [22mspecifies the area within the
axes---0,0 is bottom left and 1,1 is top right (for splot, 0,0,0 is
bottom left of plotting area; use negative z to get to the
base---see [1mset ticslevel[22m); [1mscreen [22mspecifies the screen area (the
entire area---not just the portion selected by [1mset size[22m), with 0,0
at bottom left and 1,1 at top right; and [1mcharacter [22mgives the posi-
tion in character widths and heights from the bottom left of the
screen area (screen 0,0), [1mcharacter [22mcoordinates depend on the chosen
font size.

If the coordinate system for x is not specified, [1mfirst [22mis used.  If
the system for y is not specified, the one used for x is adopted.

In some cases, the given coordinate is not an absolute position but
a relative value (e.g., the second position in [1mset arrow [22m... [1mrto[22m).
In most cases, the given value serves as difference to the first
position.  If the given coordinate resides in a logarithmic axis the
value is interpreted as factor. For example,

      set logscale x
      set arrow 100,5 rto 10,2

plots an arrow from position 100,5 to position 1000,7 since the x
axis is logarithmic while the y axis is linear.

If one (or more) axis is timeseries, the appropriate coordinate
should be given as a quoted time string according to the [1mtimefmt[0m
format string.  See [1mset xdata [22mand [1mset timefmt[22m.  [1mgnuplot [22mwill also
accept an integer expression, which will be interpreted as seconds
from 1 January 2000.



[1m12.  Datastrings[0m


The configuration option --enable-datastrings allows gnuplot to read
and process text fields in datafiles. A text field consists of
either an arbitrary string of printable characters containing no
whitespace or an arbitrary string of characters, possibly including
whitespace, delimited by double quotes.  The following sample line
from a datafile is interpreted to contain four columns, with a text










GNUPLOT 4.1                                                       18


field in column 3:

  1.000 2.000 "Third column is all of this text" 4.00

Text fields can be positioned within a 2-D or 3-D plot using the
commands:

  plot 'datafile' using 1:2:4 with labels
  splot 'datafile using 1:2:3:4 with labels

A column of text data can also be used to label the ticmarks along
one or more of the plot axes. The example below plots a line through
a series of points with (X,Y) coordinates taken from columns 3 and 4
of the input datafile.  However, rather than generating regularly
spaced tics along the x axis labeled numerically, gnuplot will posi-
tion a tic mark along the x axis at the X coordinate of each point
and label the tic mark with text taken from column 1 of the input
datafile.

  set xtics
  plot 'datafile' using 3:4:xticlabels(1) with linespoints

There is also an option that will interpret the first entry in a
column of input data as a text field, and use it as the key title
for data plotted from that column. The example given below will use
the first entry in column 2 to generate a title in the key box,
while processing the remainder of columns 2 and 4 to draw the
required line:

  plot 'datafile' using 1:(f($2)/$4) title 2 with lines

See [1mset style labels[22m, [1musing xticlabels[22m, [1mplot title[22m, [1musing[22m.



[1m13.  Environment[0m


A number of shell environment variables are understood by [1mgnuplot[22m.
None of these are required, but may be useful.

If GNUTERM is defined, it is used as the name of the terminal type
to be used.  This overrides any terminal type sensed by [1mgnuplot [22mon
start-up, but is itself overridden by the .gnuplot (or equivalent)
start-up file (see [1mstart-up[22m) and, of course, by later explicit
changes.

On Unix, AmigaOS, AtariTOS, MS-DOS and OS/2, GNUHELP may be defined
to be the pathname of the HELP file (gnuplot.gih).

On VMS, the logical name GNUPLOT$HELP should be defined as the name
of the help library for [1mgnuplot[22m.  The [1mgnuplot [22mhelp can be put inside
any system help library, allowing access to help from both within










GNUPLOT 4.1                                                       19


and outside [1mgnuplot [22mif desired.

On Unix, HOME is used as the name of a directory to search for a
.gnuplot file if none is found in the current directory.  On Ami-
gaOS, AtariTOS, MS-DOS, Windows and OS/2, GNUPLOT is used.  On Win-
dows, the NT-specific variable USERPROFILE is tried, too. VMS,
SYS$LOGIN: is used. Type [1mhelp start-up[22m.

On Unix, PAGER is used as an output filter for help messages.

On Unix, AtariTOS and AmigaOS, SHELL is used for the [1mshell [22mcommand.
On MS-DOS and OS/2, COMSPEC is used for the [1mshell [22mcommand.

On MS-DOS, if the BGI or Watcom interface is used, PCTRM is used to
tell the maximum resolution supported by your monitor by setting it
to S<max. horizontal resolution>. E.g. if your monitor's maximum
resolution is 800x600, then use:
      set PCTRM=S800
If PCTRM is not set, standard VGA is used.

FIT_SCRIPT may be used to specify a [1mgnuplot [22mcommand to be executed
when a fit is interrupted---see [1mfit[22m.  FIT_LOG specifies the default
filename of the logfile maintained by fit.

GNUPLOT_LIB may be used to define additional search directories for
data and command files. The variable may contain a single directory
name, or a list of directories separated by a platform-specific path
separator, eg. ':' on Unix, or ';' on DOS/Windows/OS/2/Amiga plat-
forms. The contents of GNUPLOT_LIB are appended to the [1mloadpath[0m
variable, but not saved with the [1msave [22mand [1msave set [22mcommands.

Several gnuplot terminal drivers access TrueType fonts via the gd
library.  For these drivers the font search path is controlled by
the environmental variable GDFONTPATH.  Furthermore, a default font
for these drivers may be set via the environmental variable GNU-
PLOT_DEFAULT_GDFONT.

The postscript terminal uses its own font search path. It is con-
trolled by the environmental variable GNUPLOT_FONTPATH. The format
is the same as for GNUPLOT_LIB. The contents of GNUPLOT_FONTPATH are
appended to the [1mfontpath [22mvariable, but not saved with the [1msave [22mand
[1msave set [22mcommands.

GNUPLOT_PS_DIR is used by the postscript driver to use external pro-
logue files. Depending on the build process, gnuplot contains either
a builtin copy of those files or simply a default hardcoded path.
Use this variable to test the postscript terminal with custom pro-
logue files. See [1mpostscript prologue[22m.















GNUPLOT 4.1                                                       20


[1m14.  Expressions[0m


In general, any mathematical expression accepted by C, FORTRAN, Pas-
cal, or BASIC is valid.  The precedence of these operators is deter-
mined by the specifications of the C programming language.  White
space (spaces and tabs) is ignored inside expressions.

Complex constants are expressed as {<real>,<imag>}, where <real> and
<imag> must be numerical constants.  For example, {3,2} represents 3
+ 2i; {0,1} represents 'i' itself.  The curly braces are explicitly
required here.

Note that gnuplot uses both "real" and "integer" arithmetic, like
FORTRAN and C.  Integers are entered as "1", "-10", etc; reals as
"1.0", "-10.0", "1e1", 3.5e-1, etc.  The most important difference
between the two forms is in division: division of integers trun-
cates: 5/2 = 2; division of reals does not: 5.0/2.0 = 2.5.  In mixed
expressions, integers are "promoted" to reals before evaluation:
5/2e0 = 2.5.  The result of division of a negative integer by a pos-
itive one may vary among compilers.  Try a test like "print -5/2" to
determine if your system chooses -2 or -3 as the answer.

The integer expression "1/0" may be used to generate an "undefined"
flag, which causes a point to ignored; the [1mternary [22moperator gives an
example.

The real and imaginary parts of complex expressions are always real,
whatever the form in which they are entered: in {3,2} the "3" and
"2" are reals, not integers.

Gnuplot can also perform simple operations on strings and string
variables.  For example, the expression ("A" . "B" eq "AB") evalu-
ates as true, illustrating the string concatenation operator and the
string equality operator.

A string which contains a numerical value is promoted to the corre-
sponding integer or real value if used in a numerical expression.
Thus ("3" + "4" == 7) and (6.78 == "6.78") both evaluate to true.
An integer, but not a real or complex value, is promoted to a string
if used in string concatenation.  A typical case is the use of inte-
gers to construct file names or other strings; e.g. ("file" . 4 eq
"file4") is true.

Substrings can be specified using a postfixed range descriptor
[beg:end].  For example, "ABCDEF"[3:4] == "CD"   and   "ABCDEF"[4:*]
== "DEF" The syntax "string"[beg:end] is exactly equivalent to call-
ing the built-in string-valued function substr("string",beg,end),
except that you cannot omit either beg or end from the function
call.













GNUPLOT 4.1                                                       21


     [1m14.1.  Functions[0m


     The functions in [1mgnuplot [22mare the same as the corresponding
     functions in the Unix math library, except that all functions
     accept integer, real, and complex arguments, unless otherwise
     noted.

     For those functions that accept or return angles that may be
     given in either degrees or radians (sin(x), cos(x), tan(x),
     asin(x), acos(x), atan(x), atan2(x) and arg(z)), the unit may
     be selected by [1mset angles[22m, which defaults to radians.



















































GNUPLOT 4.1                                                       22


+---------------------------------------------------------------------------------+
|  Function      Arguments    Returns                                             |
+---------------------------------------------------------------------------------+
|   abs(x)          any       absolute value of [4mx[24m, |[4mx[24m|; same type                 |
|   abs(x)        complex     length of [4mx[24m, real([4mx[24m)2+imag([4mx[24m)2                      |
|  acos(x)          any       cos-1[4mx[24m (inverse cosine)                             |
|  acosh(x)         any       cosh-1[4mx[24m (inverse hyperbolic cosine) in radians      |
|   arg(x)        complex     the phase of [4mx[24m                                      |
|  asin(x)          any       sin-1[4mx[24m (inverse sin)                                |
|  asinh(x)         any       sinh-1[4mx[24m (inverse hyperbolic sin) in radians         |
|  atan(x)          any       tan-1[4mx[24m (inverse tangent)                            |
| atan2(y,x)    int or real   tan-1([4my[24m/[4mx[24m) (inverse tangent)                        |
|  atanh(x)         any       tanh-1[4mx[24m (inverse hyperbolic tangent) in radians     |
|  besj0(x)     int or real   [4mj[24m0 Bessel function of [4mx[24m, in radians                 |
|  besj1(x)     int or real   [4mj[24m1 Bessel function of [4mx[24m, in radians                 |
|  besy0(x)     int or real   [4my[24m0 Bessel function of [4mx[24m, in radians                 |
|  besy1(x)     int or real   [4my[24m1 Bessel function of [4mx[24m, in radians                 |
|  ceil(x)          any       |[4mx[24m|, smallest integer not less than [4mx[24m (real part)   |
|   cos(x)        radians     cos[4mx[24m, cosine of [4mx[24m                                   |
|  cosh(x)          any       cosh[4mx[24m, hyperbolic cosine of [4mx[24m in radians            |
|   erf(x)          any       [4merf[24m(real([4mx[24m)), error function of real ([4mx[24m)            |
|  erfc(x)          any       [4merfc[24m(real([4mx[24m)), 1.0 - error function of real ([4mx[24m)     |
|   exp(x)          any       [4mex[24m, exponential function of [4mx[24m                       |
|  floor(x)         any       |[4mx[24m|, largest integer not greater than [4mx[24m (real part) |
|  gamma(x)         any       (real([4mx[24m)), gamma function of real ([4mx[24m)               |
|ibeta(p,q,x)       any       [4mibeta[24m(real([4mp[24m,[4mq[24m,[4mx[24m)), ibeta function of real ([4mp[24m,[4mq[24m,[4mx[24m)  |
| inverf(x)         any       inverse error function real([4mx[24m)                      |
|igamma(a,x)        any       [4migamma[24m(real([4ma[24m,[4mx[24m)), igamma function of real ([4ma[24m,[4mx[24m)    |
|  imag(x)        complex     imaginary part of [4mx[24m as a real number                |
| invnorm(x)        any       inverse normal distribution function real([4mx[24m)        |
|   int(x)         real       integer part of [4mx[24m, truncated toward zero            |
|lambertw(x)       real       Lambert W function                                  |
| lgamma(x)         any       [4mlgamma[24m(real([4mx[24m)), lgamma function of real ([4mx[24m)        |
|   log(x)          any       ln[4mx[24m, natural logarithm (base [4me[24m) of [4mx[24m                |
|  log10(x)         any       log10[4mx[24m, logarithm (base 10) of [4mx[24m                    |
|  norm(x)          any       [4mnorm[24m([4mx[24m), normal distribution function of real([4mx[24m)    |
|  rand(x)          any       [4mrand[24m([4mx[24m), pseudo random number generator             |
|  real(x)          any       real part of [4mx[24m                                      |
|   sgn(x)          any       1 if [4mx[24m>0, -1 if [4mx[24m<0, 0 if [4mx[24m=0. imag([4mx[24m) ignored      |
|   sin(x)          any       sin[4mx[24m, sine of [4mx[24m                                     |
|  sinh(x)          any       sinh[4mx[24m, hyperbolic sine of [4mx[24m in radians              |
|  sqrt(x)          any       [4mx[24m, square root of [4mx[24m                                 |
|   tan(x)          any       tan[4mx[24m, tangent of [4mx[24m                                  |
|  tanh(x)          any       tanh[4mx[24m, hyperbolic tangent of [4mx[24m in radians           |
+---------------------------------------------------------------------------------+


















GNUPLOT 4.1                                                       23


+----------------------------------------------------------------------------------------------+
|        Function            Arguments    Returns                                              |
+----------------------------------------------------------------------------------------------+
|  gprintf("format",x)          any       string result from applysing gnuplot's format parser |
|sprintf("format",x,...)     multiple     string result from C-language sprintf                |
|    strlen("string")         string      int length of string                                 |
|strstrt("string","key")      strings     int index of first character of substring "key"      |
|substr("string",beg,end)    multiple     string "string"[beg:end]                             |
|   system("command")         string      stdout containing output stream of shell command     |
|    word("string",n)       string, int   returns the nth word in "string"                     |
|    words("string")          string      returns the number of words in "string"              |
+----------------------------------------------------------------------------------------------+






+----------------------------------------------------------------------------------------------+
|   Function          Arguments      Returns                                                   |
+----------------------------------------------------------------------------------------------+
|   column(x)            int          column [4mx[24m during datafile manipulation.                   |
|  defined(X)       variable name     [DEPRECATED] returns 1 if X is defined, 0 otherwise.     |
|  exists("X")     "variable name"    returns 1 if a variable named X is defined, 0 otherwise. |
|stringcolumn(x)         int          content column [4mx[24m as a string.                            |
| timecolumn(x)          int          timecolumn [4mx[24m during datafile manipulation.               |
|  tm_hour(x)            int         the hour                                                  |
|  tm_mday(x)            int         the day of the month                                      |
|   tm_min(x)            int         the minute                                                |
|   tm_mon(x)            int         the month                                                 |
|   tm_sec(x)            int         the second                                                |
|  tm_wday(x)            int         the day of the week                                       |
|  tm_yday(x)            int         the day of the year                                       |
|  tm_year(x)            int         the year                                                  |
|   valid(x)             int          test validity of column([4mx[24m) during datafile manip.        |
+----------------------------------------------------------------------------------------------+


See also airfoil.dem: use of functions and complex variables for
airfoils demo.





          [1m14.1.1.  Random number generator[0m


          The behavior of the built-in function [1mrand(x) [22mhas changed
          as of version 3.8l.  Older scripts that expected rand(x>0)
          to produce sequential pseudo-random numbers from the same
          seeded sequence must be changed to call rand(0) instead.
          The current behavior is as follows:










GNUPLOT 4.1                                                       24


           `rand(0)`  returns a pseudo random number in the interval
          [0:1] generated
                      from the current value of two internal 32-bit
          seeds.
           `rand(-1)` resets both seeds to a standard value.
           `rand(x)`  for x>0 sets both seeds to a value based on
          the value of x.
           `rand({x,y})` for x>0 sets seed1 to x and seed2 to y.




     [1m14.2.  Operators[0m


     The operators in [1mgnuplot [22mare the same as the corresponding
     operators in the C programming language, except that all opera-
     tors accept integer, real, and complex arguments, unless other-
     wise noted.  The ** operator (exponentiation) is supported, as
     in FORTRAN.

     Parentheses may be used to change order of evaluation.




          [1m14.2.1.  Unary[0m


          The following is a list of all the unary operators and
          their usages:







 +-----------------------------------------------------------------+
 |Symbol   Example   Explanation                                   |
 +-----------------------------------------------------------------+
 |  -        -a      unary minus                                   |
 |  +        +a      unary plus (no-operation)                     |
 |  ~        ~a      * one's complement                            |
 |  !        !a      * logical negation                            |
 |  !        a!      * factorial                                   |
 |  $        $3      * call arg/column during `using` manipulation |
 +-----------------------------------------------------------------+
 +-----------------------------------------------------------------+


(*) Starred explanations indicate that the operator requires an
integer argument.










GNUPLOT 4.1                                                       25


Operator precedence is the same as in Fortran and C.  As in those
languages, parentheses may be used to change the order of operation.
Thus -2**2 = -4, but (-2)**2 = 4.

The factorial operator returns a real number to allow a greater
range.



          [1m14.2.2.  Binary[0m


          The following is a list of all the binary operators and
          their usages:




           +--------------------------------------------+
           |Symbol   Example   Explanation              |
           +--------------------------------------------+
           |  **      a**b     exponentiation           |
           |  *        a*b     multiplication           |
           |  /        a/b     division                 |
           |  %        a%b     * modulo                 |
           |  +        a+b     addition                 |
           |  -        a-b     subtraction              |
           |  ==      a==b     equality                 |
           |  !=      a!=b     inequality               |
           |  <        a<b     less than                |
           |  <=      a<=b     less than or equal to    |
           |  >        a>b     greater than             |
           |  >=      a>=b     greater than or equal to |
           |  &        a&b     * bitwise AND            |
           |  ^        a^b     * bitwise exclusive OR   |
           |  |        a|b     * bitwise inclusive OR   |
           |  &&      a&&b     * logical AND            |
           |  ||      a||b     * logical OR             |
           |  eq     A eq B    string equality          |
           |  ne     A ne B    string inequality        |
           +--------------------------------------------+


(*) Starred explanations indicate that the operator requires integer
arguments.  Capital letters A and B indicate that the operator
requires string arguments.

Logical AND (&&) and OR (||) short-circuit the way they do in C.
That is, the second [1m&& [22moperand is not evaluated if the first is
false; the second [1m|| [22moperand is not evaluated if the first is true.













GNUPLOT 4.1                                                       26


          [1m14.2.3.  Ternary[0m


          There is a single ternary operator:




              +---------------------------------------+
              |Symbol   Example   Explanation         |
              +---------------------------------------+
              |  ?:      a?b:c    * ternary operation |
              +---------------------------------------+


The ternary operator behaves as it does in C.  The first argument
(a), which must be an integer, is evaluated.  If it is true (non-
zero), the second argument (b) is evaluated and returned; otherwise
the third argument (c) is evaluated and returned.

The ternary operator is very useful both in constructing piecewise
functions and in plotting points only when certain conditions are
met.

Examples:

Plot a function that is to equal sin(x) for 0 <= x < 1, 1/x for 1 <=
x < 2, and undefined elsewhere:
      f(x) = 0<=x && x<1 ? sin(x) : 1<=x && x<2 ? 1/x : 1/0
      plot f(x)
Note that [1mgnuplot [22mquietly ignores undefined values, so the final
branch of the function (1/0) will produce no plottable points.  Note
also that f(x) will be plotted as a continuous function across the
discontinuity if a line style is used.  To plot it discontinuously,
create separate functions for the two pieces.  (Parametric functions
are also useful for this purpose.)

For data in a file, plot the average of the data in columns 2 and 3
against the datum in column 1, but only if the datum in column 4 is
non-negative:

      plot 'file' using 1:( $4<0 ? 1/0 : ($2+$3)/2 )

Please see [1mplot datafile using [22mfor an explanation of the [1musing [22msyn-
tax.




     [1m14.3.  Gnuplot-defined variables[0m













GNUPLOT 4.1                                                       27


     The variable [1mpi [22mis defined to be pi, see
           print pi

     Additionally, gnuplot may define some variables under various
     operations.

     Working with interactive terminals with [1mmouse [22mfunctionality
     defines variables with names that begin "MOUSE_", see [1mmouse[0m
     [1mvariables [22mfor details.

     Further, there are several "read-only" variables that begin
     "GPVAL_", like GPVAL_TERM, GPVAL_X_MIN, GPVAL_X_MAX,
     GPVAL_Y_MIN,... Type [1mshow variables all [22mto display their list
     and values. Values related to axes parameters (ranges, log
     base) are values used during the last plot, not those currently
     [1mset[22m.

     The [1mfit [22mmechanism uses several variables with names that begin
     "FIT_".  It is safest to avoid using such names.  "FIT_LIMIT",
     however, is one that you may wish to redefine. Under [1mset fit[0m
     [1merrorvariables[22m, the error for each fitted parameter will be
     stored in a variable named like the parameter, but with "_err"
     appended. See the documentation on [1mfit [22mfor details.

     See [1muser-defined variables[22m, [1mmouse variables[22m, and [1mfit[22m.




     [1m14.4.  User-defined variables and functions[0m


     New user-defined variables and functions of one through five
     variables may be declared and used anywhere, including on the
     [1mplot [22mcommand itself.

     User-defined function syntax:
           <func-name>( <dummy1> {,<dummy2>} ... {,<dummy5>} ) =
     <expression>

     where <expression> is defined in terms of <dummy1> through
     <dummy5>.

     User-defined variable syntax:
           <variable-name> = <constant-expression>

     Examples:
           w = 2
           q = floor(tan(pi/2 - 0.1))
           f(x) = sin(w*x)
           sinc(x) = sin(pi*x)/(pi*x)
           delta(t) = (t == 0)
           ramp(t) = (t > 0) ? t : 0










GNUPLOT 4.1                                                       28


           min(a,b) = (a < b) ? a : b
           comb(n,k) = n!/(k!*(n-k)!)
           len3d(x,y,z) = sqrt(x*x+y*y+z*z)
           plot f(x) = sin(x*a), a = 0.2, f(x), a = 0.4, f(x)

           file = "mydata.inp"
           file(n) = sprintf("run_%d.dat",n)

     The final two examples illustrate a user-defined string vari-
     able and a user-defined string function.

     Note that the variable [1mpi [22mis already defined.  But it is in no
     way magic; you may redefine it to be whatever you like. Some
     other variables may be defined under various gnuplot operations
     like mousing in interactive terminals or fitting; see [1mgnuplot-[0m
     [1mdefined variables [22mfor details.

     You can check for existence of a given variable V by the
     exists("V") expression. For example
           a = 10
           if (exists("a")) print "a is defined"
           if (!exists("b")) print "b is not defined"

     Valid names are the same as in most programming languages: they
     must begin with a letter, but subsequent characters may be let-
     ters, digits, "$", or "_".

     See [1mshow functions[22m, [1mfunctions[22m, [1mgnuplot-defined variables[22m,
     [1mmacros[22m.



[1m15.  Glossary[0m


Throughout this document an attempt has been made to maintain con-
sistency of nomenclature.  This cannot be wholly successful because
as [1mgnuplot [22mhas evolved over time, certain command and keyword names
have been adopted that preclude such perfection.  This section con-
tains explanations of the way some of these terms are used.

A "page" or "screen" is the entire area addressable by [1mgnuplot[22m.  On
a monitor, it is the full screen; on a plotter, it is a single sheet
of paper.

A screen may contain one or more "plots".  A plot is defined by an
abscissa and an ordinate, although these need not actually appear on
it, as well as the margins and any text written therein.

A plot contains one "graph".  A graph is defined by an abscissa and
an ordinate, although these need not actually appear on it.

A graph may contain one or more "lines".  A line is a single










GNUPLOT 4.1                                                       29


function or data set.  "Line" is also a plotting style.  The word
will also be used in sense "a line of text".  Presumably the context
will remove any ambiguity.

The lines on a graph may have individual names.  These may be listed
together with a sample of the plotting style used to represent them
in the "key", sometimes also called the "legend".

The word "title" occurs with multiple meanings in [1mgnuplot[22m.  In this
document, it will always be preceded by the adjective "plot",
"line", or "key" to differentiate among them.

A 2-d graph may have up to four labelled axes.  The names of the
four axes for these usages are "x" for the axis along the bottom
border of the plot, "y" for the left border, "x2" for the top bor-
der, and "y2" for the right border.

A 3-d graph may have up to three labelled axes -- "x", "y" and "z".
It is not possible to say where on the graph any particular axis
will fall because you can change the direction from which the graph
is seen with [1mset view[22m.

When discussing data files, the term "record" will be resurrected
and used to denote a single line of text in the file, that is, the
characters between newline or end-of-record characters.  A "point"
is the datum extracted from a single record.  A "datablock" is a set
of points from consecutive records, delimited by blank records.  A
line, when referred to in the context of a data file, is a subset of
a datablock.



[1m16.  Linetype, colors, and styles[0m


Each gnuplot terminal type provides a set of distinct "linetypes".
These may differ in color, in thickness, in dot/dash pattern, or in
some combination of color and dot/dash. The default linetypes for a
particular terminal can be previewed by issuing the [1mtest [22mcommand
after setting the terminal type.  The pre-defined colors and
dot/dash patterns are not guaranteed to be consistent for all termi-
nal types, but all terminals use the special linetype -1 to mean a
solid line in the primary foreground color (normally black).  By
default, successive functions or datafiles plotted by a single com-
mand will be assigned successive linetypes.  You can override this
default by specifying a particular linetype for any function,
datafile, or plot element.

Examples:

     plot "foo", "bar"                 # plot two files using line-
types 1, 2
     plot sin(x) linetype 4            # terminal-specific linetype










GNUPLOT 4.1                                                       30


color 4
     plot sin(x) lt -1                 # black

For many terminal types it is also possible to assign user-defined
colors using explicit rgb (red, green, blue) values, named colors,
or color values that refer to the current PM3D palette.

Examples:

     plot sin(x) lt rgb "violet"       # one of gnuplot's named col-
ors
     plot sin(x) lt rgb "#FF00FF"      # explicit RGB triple in hex-
adecimal
     plot sin(x) lt palette cb -45     # whatever color corresponds
to -45
                                       # in the current cbrange of
the palette
     plot sin(x) lt palette frac 0.3   # fractional value along the
palette

See [1mshow palette colornames[22m, [1mset palette[22m, [1mcbrange[22m.

For terminals that support dot/dash patterns, each default linetype
has both a dot-dash pattern and a default color. However, you can
override the default color by using the keyword [1mlinecolor[22m, abbrevi-
ated [1mlc[22m.  For example, the postscript terminal provides a dashed
blue line as linetype 3.  The plot commands below use this same dash
pattern for three plots, one in blue (the default), another in red
(the default for linetype 1), and a third in gold.

Example:

     set term postscript dashed color
     plot 'foo' lt 3, 'baz' lt 3 linecolor 1, 'bar' lt 3 lc rgb
'gold'

Lines can have additional properties such as linewidth.  You can as-
sociate these various properties, as well as equivalent properties
for point symbols, into user-defined "line styles" using the command
[1mset style line[22m.  Once you have defined a linestyle, you can use it
in a plot command to control the appearance of one or more plot ele-
ments.

Examples:

     # define a new line style with terminal-independent color cyan,
     # linewidth 3, and associated point type 6 (a circle with a dot
in it).
     set style line 5 lt rgb "cyan" lw 3 pt 6
     plot sin(x) with linespoints ls 5          # user-defined line
style 5

See [1mlinestyle[22m, [1mset style line[22m.










GNUPLOT 4.1                                                       31


     [1m16.1.  Colorspec[0m


     Many commands allow you to specify a linetype with an explicit
     color. This option is only possible for terminals that support
     RGB color or pm3d palettes.

     Syntax:

           ... {linetype | lt} <colorspec>

     where <colorspec> has one of the following forms:

           rgbcolor "colorname"
           rgbcolor "#RRGGBB"
           rgbcolor variable
           palette frac <val>      # <val> runs from 0 to 1
           palette cb <value>      # <val> lies within cbrange
           palette z

     "colorname" refers to one of the color names built in to gnu-
     plot. For a list of the available names, see [1mshow palette col-[0m
     [1mornames[22m.

     "#RRGGBB" is a hexadecimal constant preceded by the "#" symbol.
     The RRGGBB represents the red, green, and blue components of
     the color, each on a scale from 0 - 255.  For example, magenta
     = full-scale red + full-scale blue would be represented by
     #FF00FF, which is the hexadecimal representation of (255 << 16)
     + (0 << 8) + (255).

     "rgb variable" requires an additional column in the [1musing [22mspec-
     ifier, and is only available in 3D plotting mode (splot). The
     extra column is interpreted as a 24-bit packed RGB triple.
     These are most easily specified in a data file as hexidecimal
     values (see above).

     Example:

           rgb(r,g,b) = 65536 * int(r) + 256 * int(g) + int(b)
           splot "data" using 1:2:3:(rgb($1,$2,$3)) with points lc
     rgb variable

     The color palette is a linear gradient of colors that smoothly
     maps a single numerical value onto a particular color.  Two
     such mappings are always in effect. [1mpalette frac  [22mmaps a frac-
     tional value between 0 and 1 onto the full range of the color
     palette.  [1mpalette cb [22mmaps the range of the color axis onto the
     same palette.  See [1mset cbrange[22m.  See also [1mset colorbox[22m.  You
     can use either of these to select a constant color from the
     current palette.

     "palette z" maps the z value of each plot segment or plot










GNUPLOT 4.1                                                       32


     element into the cbrange mapping of the palette. This allows
     smoothly-varying color along a 3d line or surface. This option
     applies only to 3D plots (splot).




[1m17.  Mouse input[0m


The [1mx11[22m, [1mpm[22m, [1mwindows[22m, [1mggi[22m, and [1mwxt [22mterminals allow interaction with
the current plot using the mouse. They also support the definition
of hotkeys to activate pre-defined functions by hitting a single key
while the mouse focus is in the active plot window.  It is even pos-
sible to combine mouse input with [1mbatch [22mcommand scripts, by invoking
the command [1mpause mouse [22mand then using the mouse variables returned
by mouse clicking as parameters for subsequent scripted actions. See
[1mbind [22mand [1mmouse variables[22m.  See also the command [1mset mouse[22m.




     [1m17.1.  Bind[0m


     The [1mbind [22mallows defining or redefining a hotkey, i.e. a
     sequence of gnuplot commands which will be executed when a cer-
     tain key or key sequence is pressed while the driver's window
     has the input focus. Note that [1mbind [22mis only available if gnu-
     plot was compiled with [1mmouse [22msupport and it is used by all
     mouse-capable terminals. Bindings overwrite the builtin bind-
     ings (like in every real editor), except <space> and 'q' which
     cannot be rebound (unless one exception, see below). Mouse but-
     tons cannot be rebound.

     You get the list of all hotkeys by typing [1mbind [22mor by hitting
     'h' in the graph window.

     Note that multikey-bindings with modifiers have to be quoted.

     Normally hotkeys are only recognized when the currently active
     plot window has focus. [1mbind allwindows <key> ... [22m(short form:
     [1mbind all <key> ...[22m)  causes the binding for <key> to apply to
     all gnuplot plot windows, active or not.  In this case gnuplot
     variable MOUSE_KEY_WINDOW is set to the ID of the originating
     window, and may be used by the bound command.

     By default, the <space> hotkey raises gnuplot's command window.
     On some terminals (e.g. x11, wx, pm), 'q' closes the graph win-
     dow. These defaults can be changed to ctrl-space and ctrl-q by
     starting gnuplot as 'gnuplot -ctrlq', see [1mx11 command-line-[0m
     [1moptions[22m, or by the X Resource 'gnuplot*ctrlq'.  Note: if
     <space> (or ctrl-space) does not raise the gnuplot window under










GNUPLOT 4.1                                                       33


     X11, see discussion in [1mraise[22m.

     Syntax:
           bind {allwindows} [<key-sequence>] ["<gnuplot commands>"]
           bind!

     Examples:

     - set bindings:

         bind a "replot"
         bind "ctrl-a" "plot x*x"
         bind "ctrl-alt-a" 'print "great"'
         bind Home "set view 60,30; replot"
         bind all Home 'print "This is window ",MOUSE_KEY_WINDOW'

     - show bindings:
         bind "ctrl-a"          # shows the binding for ctrl-a
         bind                   # shows all bindings

     - remove bindings:
         bind "ctrl-alt-a" ""   # removes binding for ctrl-alt-a
                                  (note that builtins cannot be
     removed)
         bind!                  # installs default (builtin) bind-
     ings

     - bind a key to toggle something:
       v=0
       bind "ctrl-r" "v=v+1;if(v%2)set term x11 noraise; else set
     term x11 raise"

     Modifiers (ctrl / alt) are case insensitive, keys not:
         ctrl-alt-a == CtRl-alT-a
         ctrl-alt-a != ctrl-alt-A

     List of modifiers (alt == meta):
         ctrl, alt

     List of supported special keys:

        "BackSpace", "Tab", "Linefeed", "Clear", "Return", "Pause",
     "Scroll_Lock",
        "Sys_Req", "Escape", "Delete", "Home", "Left", "Up",
     "Right", "Down",
        "PageUp", "PageDown", "End", "Begin",

        "KP_Space", "KP_Tab", "KP_Enter", "KP_F1", "KP_F2", "KP_F3",
     "KP_F4",
        "KP_Home", "KP_Left", "KP_Up", "KP_Right", "KP_Down",
     "KP_PageUp",
        "KP_PageDown", "KP_End", "KP_Begin", "KP_Insert",
     "KP_Delete", "KP_Equal",










GNUPLOT 4.1                                                       34


        "KP_Multiply", "KP_Add", "KP_Separator", "KP_Subtract",
     "KP_Decimal",
        "KP_Divide",

        "KP_1" - "KP_9", "F1" - "F12"

     See also help for [1mmouse [22mand [1mif[22m.




     [1m17.2.  Mouse variables[0m


     When mousing is active, clicking in the active window will set
     several user variables that can be accessed from the gnuplot
     command line. The coordinates of the mouse at the time of the
     click are stored in MOUSE_X MOUSE_Y MOUSE_X2 and MOUSE_Y2. The
     mouse button clicked, and any meta-keys active at that time,
     are stored in MOUSE_BUTTON MOUSE_SHIFT MOUSE_ALT and
     MOUSE_CTRL.  These variables are set to undefined at the start
     of every plot, and only become defined in the event of a mouse
     click in the active plot window. To determine from a script if
     the mouse has been clicked in the active plot window, it is
     sufficient to test for any one of these variables being
     defined.

           plot 'something'
           pause mouse
           if (defined(MOUSE_BUTTON)) call 'something_else'; \
           else print "No mouse click."

     It is also possible to track keystrokes in the plot window
     using the mousing code.

           plot 'something'
           pause mouse keypress
           print "Keystroke ", MOUSE_KEY, " at ", MOUSE_X, " ",
     MOUSE_Y

     When [1mpause mouse keypress [22mis terminated by a keypress, then
     MOUSE_KEY will contain the ascii character value of the key
     that was pressed. MOUSE_CHAR will contain the character itself
     as a string variable.  If the pause command is terminated
     abnormally (e.g. by ctrl-C or by externally closing the plot
     window) then MOUSE_KEY will equal -1.

     Note that after a zoom by mouse, you can read the new ranges as
     GPVAL_X_MIN, GPVAL_X_MAX, GPVAL_Y_MIN, and GPVAL_Y_MAX, see
     [1mgnuplot-defined variables[22m.













GNUPLOT 4.1                                                       35


[1m18.  Plotting[0m


There are three [1mgnuplot [22mcommands which actually create a plot: [1mplot[22m,
[1msplot [22mand [1mreplot[22m.  [1mplot [22mgenerates 2-d plots, [1msplot [22mgenerates 3-d
plots (actually 2-d projections, of course), and [1mreplot [22mappends its
arguments to the previous [1mplot [22mor [1msplot [22mand executes the modified
command.

Much of the general information about plotting can be found in the
discussion of [1mplot[22m; information specific to 3-d can be found in the
[1msplot [22msection.

[1mplot [22moperates in either rectangular or polar coordinates -- see [1mset[0m
[1mpolar [22mfor details of the latter.  [1msplot [22moperates only in rectangular
coordinates, but the [1mset mapping [22mcommand allows for a few other
coordinate systems to be treated.  In addition, the [1musing [22moption
allows both [1mplot [22mand [1msplot [22mto treat almost any coordinate system
you'd care to define.

[1mplot [22malso lets you use each of the four borders -- x (bottom), x2
(top), y (left) and y2 (right) -- as an independent axis.  The [1maxes[0m
option lets you choose which pair of axes a given function or data
set is plotted against.  A full complement of [1mset [22mcommands exists to
give you complete control over the scales and labelling of each
axis.  Some commands have the name of an axis built into their
names, such as [1mset xlabel[22m.  Other commands have one or more axis
names as options, such as [1mset logscale xy[22m.  Commands and options
controlling the z axis have no effect on 2-d graphs.

[1msplot [22mcan plot surfaces and contours in addition to points and/or
lines.  In addition to [1msplot[22m, see [1mset isosamples [22mfor information
about defining the grid for a 3-d function;  [1msplot datafile [22mfor
information about the requisite file structure for 3-d data values;
and [1mset contour [22mand [1mset cntrparam [22mfor information about contours.

In [1msplot[22m, control over the scales and labels of the axes are the
same as with [1mplot[22m, except that commands and options controlling the
x2 and y2 axes have no effect whereas of course those controlling
the z axis do take effect.



[1m19.  Start-up[0m


When [1mgnuplot [22mis run, it looks for an initialization file to load.
This file is called [1m.gnuplot [22mon Unix and AmigaOS systems, and [1mGNU-[0m
[1mPLOT.INI [22mon other systems.  If this file is not found in the current
directory, the program will look for it in the HOME directory (under
AmigaOS, Atari(single)TOS, MS-DOS, Windows and OS/2, the environment
variable [1mGNUPLOT [22mshould contain the name of this directory; on Win-
dows NT, it will use [1mUSERPROFILE [22mif GNUPLOT isn't defined).  Note:










GNUPLOT 4.1                                                       36


if NOCWDRC is defined during the installation, [1mgnuplot [22mwill not read
from the current directory.

If the initialization file is found, [1mgnuplot [22mexecutes the commands
in it.  These may be any legal [1mgnuplot [22mcommands, but typically they
are limited to setting the terminal and defining frequently-used
functions or variables.



[1m20.  String constants and string variables[0m


In addition to string constants, most gnuplot commands also accept a
string variable, a string expression, or a function that returns a
string.  For example, the following four methods of creating a plot
all result in the same plot title:

      four = "4"
      graph4 = "Title for plot #4"
      graph(n) = sprintf("Title for plot #%d",n)

      plot 'data.4' title "Title for plot #4"
      plot 'data.4' title graph4
      plot 'data.4' title "Title for plot #".four
      plot 'data.4' title graph(4)

Since integers are promoted to strings when operated on by the
string concatenation operator, the following method also works:

      N = 4
      plot 'data.'.N title "Title for plot #".N

In general, elements on the command line will only be evaluated as
possible string variables if they are not otherwise recognizable as
part of the normal gnuplot syntax. So the following sequence of com-
mands is legal, although probably should be avoided so as not to
cause confusion:

      plot = "my_datafile.dat"
      title = "My Title"
      plot plot title title

There are three binary operators that require string operands: the
string concatenation operator ".", the string equality operator "eq"
and the string inequality operator "ne".  The following example will
print TRUE.

     if ("A"."B" eq "AB") print "TRUE"

See also the two string formatting functions [1mgprintf [22mand [1msprintf[22m.

Substrings can be specified by appending a range specifier to any










GNUPLOT 4.1                                                       37


string, string variable, or string-valued function.  The range spec-
ifier has the form [begin:end], where begin is the index of the
first character of the substring and end is the index of the last
character of the substring.  The first character has index 1.  The
begin or end fields may be empty, or contain '*', to indicate the
true start or end of the original string.  E.g.  str[:] and str[*:*]
both describe the full string str.



[1m21.  Substitution and Command line macros[0m


When a command line to gnuplot is first read, i.e. before it is
interpreted or executed, two forms of lexical substitution are per-
formed. These are triggered by the presence of text in backquotes
(ascii character 96) or preceded by @ (ascii character 64).




     [1m21.1.  Substitution of system commands in backquotes[0m


     Command-line substitution is specified by a system command
     enclosed in backquotes.  This command is spawned and the output
     it produces replaces the backquoted text on the command line.
     Some implementations also support pipes;  see [1mplot datafile[0m
     [1mspecial-filenames[22m.

     Command-line substitution can be used anywhere on the [1mgnuplot[0m
     command line, except inside strings delimited by single quotes.

     Example:

     This will run the program [1mleastsq [22mand replace [1mleastsq [22m(includ-
     ing backquotes) on the command line with its output:
           f(x) = `leastsq`

     or, in VMS
           f(x) = `run leastsq`

     These will generate labels with the current time and userid:
           set label "generated on `date +%Y-%m-%d` by `whoami`" at
     1,1
           set timestamp "generated on %Y-%m-%d by `whoami`"



     [1m21.2.  Substitution of string variables as macros[0m













GNUPLOT 4.1                                                       38


     Substitution of command line macros is disabled by default, but
     may be enabled using the [1mset macros [22mcommand.  If macro substi-
     tution is enabled, the character @ is used to trigger substitu-
     tion of the current value of a string variable into the command
     line. The text in the string variable may contain any number of
     lexical elements.  This allows string variables to be used as
     command line macros.  Only string constants may be expanded
     using this mechanism, not string-valued expressions.  For exam-
     ple:

           set macros
           style1 = "lines lt 4 lw 2"
           style2 = "points lt 3 pt 5 ps 2"
           range1 = "using 1:3"
           range2 = "using 1:5"
           plot "foo" @range1 with @style1, "bar" @range2 with
     @style2

     The line containing @ symbols is expanded on input, so that by
     the time it is executed the effect is identical to having typed
     in full

           plot "foo" using 1:3 with lines lt 4 lw 2, \
                "bar" using 1:5 with points lt 3 pt 5 ps 2

     The function exists() may be useful in connection with macro
     evaluation.  The following example checks that C can safely be
     expanded as the name of a user-defined variable:

           C = "pi"
           if (exists(C)) print C," = ", @C

     Macro expansion does not occur inside either single or double
     quotes.  However macro expansion does occur inside backquotes.



     [1m21.3.  String variables, macros, and command line substitution[0m


     The interaction of string variables, backquotes and macro sub-
     stitution is somewhat complicated.  Backquotes do not block
     macro substitution, so

           filename = "mydata.inp"
           lines = ` wc --lines @filename | sed "s/ .*//" `

     results in the number of lines in mydata.inp being stored in
     the integer variable lines. And double quotes do not block
     backquote substitution, so

           mycomputer = "`uname -n`"











GNUPLOT 4.1                                                       39


     results in the string returned by the system command [1muname -n[0m
     being stored in the string variable mycomputer.

     However, macro substitution is not performed inside double
     quotes, so you cannot define a system command as a macro and
     then use both macro and backquote substitution at the same
     time.

            machine_id = "uname -n"
            mycomputer = "`@machine_id`"  # doesn't work!!

     This fails because the double quotes prevent @machine_id from
     being interpreted as a macro. To store a system command as a
     macro and execute it later you must instead include the back-
     quotes as part of the macro itself.  This is accomplished by
     defining the macro as shown below.  Notice that the sprintf
     format nests all three types of quotes.

           machine_id = sprintf('"`uname -n`"')
           mycomputer = @machine_id



[1m22.  Syntax[0m


Version 4 of gnuplot is much less sensitive than earlier versions to
the order of keywords and suboptions. However, if you get error mes-
sages from specifying options that you think should work, please try
rearranging them into the exact order listed by the documentation.

Options and any accompanying parameters are separated by spaces
whereas lists and coordinates are separated by commas.  Ranges are
separated by colons and enclosed in brackets [], text and file names
are enclosed in quotes, and a few miscellaneous things are enclosed
in parentheses.  Braces {} are used for a few special purposes.

Commas are used to separate coordinates on the [1mset [22mcommands [1marrow[22m,
[1mkey[22m, and [1mlabel[22m; the list of variables being fitted (the list after
the [1mvia [22mkeyword on the [1mfit [22mcommand); lists of discrete contours or
the loop parameters which specify them on the [1mset cntrparam [22mcommand;
the arguments of the [1mset [22mcommands [1mdgrid3d[22m, [1mdummy[22m, [1misosamples[22m, [1moff-[0m
[1msets[22m, [1morigin[22m, [1msamples[22m, [1msize[22m, [1mtime[22m, and [1mview[22m; lists of tics or the
loop parameters which specify them; the offsets for titles and axis
labels; parametric functions to be used to calculate the x, y, and z
coordinates on the [1mplot[22m, [1mreplot [22mand [1msplot [22mcommands; and the complete
sets of keywords specifying individual plots (data sets or func-
tions) on the [1mplot[22m, [1mreplot [22mand [1msplot [22mcommands.

Parentheses are used to delimit sets of explicit tics (as opposed to
loop parameters) and to indicate computations in the [1musing [22mfilter of
the [1mfit[22m, [1mplot[22m, [1mreplot [22mand [1msplot [22mcommands.











GNUPLOT 4.1                                                       40


(Parentheses and commas are also used as usual in function nota-
tion.)

Square brackets are used to delimit ranges given in [1mset[22m, [1mplot [22mor
[1msplot [22mcommands.

Colons are used to separate extrema in [1mrange [22mspecifications (whether
they are given on [1mset[22m, [1mplot [22mor [1msplot [22mcommands) and to separate
entries in the [1musing [22mfilter of the [1mplot[22m, [1mreplot[22m, [1msplot [22mand [1mfit [22mcom-
mands.

Semicolons are used to separate commands given on a single command
line.

Braces are used in text to be specially processed by some terminals,
like [1mpostscript[22m.  They are also used to denote complex numbers:
{3,2} = 3 + 2i.

At present you should not embed \n inside {} when using the
PostScript terminal in [1menhanced text [22mmode.

The EEPIC, Imagen, Uniplex, LaTeX, and TPIC drivers allow a newline
to be specified by \\ in a single-quoted string or \\\\ in a double-
quoted string.




     [1m22.1.  Quote Marks[0m


     Gnuplot uses three forms of quote marks for delimiting text
     strings, double-quote (ascii 34), single-quote (ascii 39), and
     backquote (ascii 96).

     Filenames may be entered with either single- or double-quotes.
     In this manual the command examples generally single-quote
     filenames and double-quote other string tokens for clarity.

     String constants and text strings used for labels, titles, or
     other plot elements may be enclosed in either single quotes or
     double quotes. Further processing of the quoted text depends on
     the choice of quote marks.

     Backslash processing of special characters like \n (newline)
     and \345 (octal character code) is performed for double-quoted
     strings.  In single-quoted strings, backslashes are just ordi-
     nary characters.  To get a single-quote (ascii 39) in a single-
     quoted string, it has to be doubled.  Thus the strings "d\" s'
     b\\" and 'd" s'' b\' are completely equivalent.

     Text justification is the same for each line of a multi-line
     string.  Thus the center-justified string










GNUPLOT 4.1                                                       41


           "This is the first line of text.\nThis is the second
     line."
     will produce
                            This is the first line of text.
                               This is the second line.
     but
           'This is the first line of text.\nThis is the second
     line.'
     will produce
               This is the first line of text.\nThis is the second
     line.

     Enhanced text processing is performed for both double-quoted
     text and single-quoted text, but only by terminals supporting
     this mode.  See [1menhanced text[22m.

     Back-quotes are used to enclose system commands for substitu-
     tion into the command line.  See [1msubstitution[22m.



[1m23.  Time/Date data[0m


[1mgnuplot [22msupports the use of time and/or date information as input
data.  This feature is activated by the commands [1mset xdata time[22m, [1mset[0m
[1mydata time[22m, etc.

Internally all times and dates are converted to the number of sec-
onds from the year 2000.  The command [1mset timefmt [22mdefines the format
for all inputs: data files, ranges, tics, label positions---in
short, anything that accepts a data value must receive it in this
format.  Since only one input format can be in force at a given
time, all time/date quantities being input at the same time must be
presented in the same format.  Thus if both x and y data in a file
are time/date, they must be in the same format.

The conversion to and from seconds assumes Universal Time (which is
the same as Greenwich Standard Time).  There is no provision for
changing the time zone or for daylight savings.  If all your data
refer to the same time zone (and are all either daylight or stan-
dard) you don't need to worry about these things.  But if the abso-
lute time is crucial for your application, you'll need to convert to
UT yourself.

Commands like [1mshow xrange [22mwill re-interpret the integer according to
[1mtimefmt[22m.  If you change [1mtimefmt[22m, and then [1mshow [22mthe quantity again,
it will be displayed in the new [1mtimefmt[22m.  For that matter, if you
give the deactivation command (like [1mset xdata[22m), the quantity will be
shown in its numerical form.

The command [1mset format [22mdefines the format that will be used for tic
labels, whether or not the specified axis is time/date.










GNUPLOT 4.1                                                       42


If time/date information is to be plotted from a file, the [1musing[0m
option _must_ be used on the [1mplot [22mor [1msplot [22mcommand.  These commands
simply use white space to separate columns, but white space may be
embedded within the time/date string.  If you use tabs as a separa-
tor, some trial-and-error may be necessary to discover how your sys-
tem treats them.

The following example demonstrates time/date plotting.

Suppose the file "data" contains records like

      03/21/95 10:00  6.02e23

This file can be plotted by

      set xdata time
      set timefmt "%m/%d/%y"
      set xrange ["03/21/95":"03/22/95"]
      set format x "%m/%d"
      set timefmt "%m/%d/%y %H:%M"
      plot "data" using 1:3

which will produce xtic labels that look like "03/21".

See the descriptions of each command for more details.




[1m24.  Commands[0m


This section lists the commands acceptable to [1mgnuplot [22min alphabeti-
cal order.  Printed versions of this document contain all commands;
on-line versions may not be complete.  Indeed, on some systems there
may be no commands at all listed under this heading.

Note that in most cases unambiguous abbreviations for command names
and their options are permissible, i.e., "[1mp f(x) w li[22m" instead of
"[1mplot f(x) with lines[22m".

In the syntax descriptions, braces ({}) denote optional arguments
and a vertical bar (|) separates mutually exclusive choices.



[1m25.  Cd[0m


The [1mcd [22mcommand changes the working directory.

Syntax:
      cd '<directory-name>'










GNUPLOT 4.1                                                       43


The directory name must be enclosed in quotes.

Examples:
      cd 'subdir'
      cd ".."

It is recommended for DOS and Windows users to use single-
quotes---backslash [\] has special significance inside double-quotes
and has to be escaped.  For example,
      cd "c:\newdata"
fails, but
      cd 'c:\newdata'
      cd "c:\\newdata"
works as expected.



[1m26.  Call[0m


The [1mcall [22mcommand is identical to the load command with one excep-
tion: you can have up to ten additional parameters to the command
(delimited according to the standard parser rules) which can be sub-
stituted into the lines read from the file.  As each line is read
from the [1mcall[22med input file, it is scanned for the sequence [1m$ [22m(dol-
lar-sign) followed by a digit (0--9).  If found, the sequence is
replaced by the corresponding parameter from the [1mcall [22mcommand line.
If the parameter was specified as a string in the [1mcall [22mline, it is
substituted without its enclosing quotes.  Sequence [1m$# [22mis replaced
by the number of passed parameters.  [1m$ [22mfollowed by any character
will be that character; e.g. use [1m$$ [22mto get a single [1m$[22m.  Providing
more than ten parameters on the [1mcall [22mcommand line will cause an
error.  A parameter that was not provided substitutes as nothing.
Files being [1mcall[22med may themselves contain [1mcall [22mor [1mload [22mcommands.

The [1mcall [22mcommand _must_ be the last command on a multi-command line.

Syntax:
      call "<input-file>" <parameter-0> <parm-1> ... <parm-9>

The name of the input file must be enclosed in quotes, and it is
recommended that parameters are similarly enclosed in quotes (future
versions of gnuplot may treat quoted and unquoted arguments differ-
ently).

Example:

If the file 'calltest.gp' contains the line:
      print "argc=$# p0=$0 p1=$1 p2=$2 p3=$3 p4=$4 p5=$5 p6=$6
p7=x$7x"

entering the command:
      call 'calltest.gp' "abcd" 1.2 + "'quoted'" -- "$2"










GNUPLOT 4.1                                                       44


will display:
      argc=7 p0=abcd p1=1.2 p2=+ p3='quoted' p4=- p5=- p6=$2 p7=xx

NOTE: there is a clash in syntax with the datafile [1musing [22mcallback
operator.  Use [1m$$n [22mor [1mcolumn(n) [22mto access column n from a datafile
inside a [1mcall[22med datafile plot.



[1m27.  Clear[0m


The [1mclear [22mcommand erases the current screen or output device as
specified by [1mset output[22m.  This usually generates a formfeed on hard-
copy devices.  Use [1mset terminal [22mto set the device type.

For some terminals [1mclear [22merases only the portion of the plotting
surface defined by [1mset size[22m, so for these it can be used in conjunc-
tion with [1mset multiplot [22mto create an inset.

Example:
      set multiplot
      plot sin(x)
      set origin 0.5,0.5
      set size 0.4,0.4
      clear
      plot cos(x)
      unset multiplot

Please see [1mset multiplot[22m, [1mset size[22m, and [1mset origin [22mfor details of
these commands.



[1m28.  Exit[0m


The commands [1mexit [22mand [1mquit[22m, as well as the END-OF-FILE character
(usually Ctrl-D) terminate input from the current input stream: ter-
minal session, pipe, and file input (pipe).

If input streams are nested (inherited [1mload [22mscripts), then reading
will continue in the parent stream. When the top level stream is
closed, the program itself will exit.

The command [1mexit gnuplot [22mwill immediately and unconditionally cause
gnuplot to exit even if the input stream is multiply nested.  In
this case any open output files may not be completed cleanly. Exam-
ple of use:

      bind "ctrl-x" "unset output; exit gnuplot"

See help for [1mbatch/interactive [22mfor more details.










GNUPLOT 4.1                                                       45


[1m29.  Fit[0m


The [1mfit [22mcommand can fit a user-defined function to a set of data
points (x,y) or (x,y,z), using an implementation of the nonlinear
least-squares (NLLS) Marquardt-Levenberg algorithm.  Any user-
defined variable occurring in the function body may serve as a fit
parameter, but the return type of the function must be real.

Syntax:
      fit {[xrange] {[yrange]}} <function> '<datafile>'
          {datafile-modifiers}
          via '<parameter file>' | <var1>{,<var2>,...}

Ranges may be specified to temporarily limit the data which is to be
fitted; any out-of-range data points are ignored. The syntax is
      [{dummy_variable=}{<min>}{:<max>}],
analogous to [1mplot[22m; see [1mplot ranges[22m.

<function> is any valid [1mgnuplot [22mexpression, although it is usual to
use a previously user-defined function of the form f(x) or f(x,y).

<datafile> is treated as in the [1mplot [22mcommand.  All the [1mplot datafile[0m
modifiers ([1musing[22m, [1mevery[22m,...) except [1msmooth [22mand the deprecated [1mthru[0m
are applicable to [1mfit[22m. See [1mplot datafile[22m.

The default data formats for fitting functions with a single inde-
pendent variable, y=f(x), are {x:}y or x:y:s; those formats can be
changed with the datafile [1musing [22mqualifier.  The third item (a column
number or an expression), if present, is interpreted as the standard
deviation of the corresponding y value and is used to compute a
weight for the datum, 1/s**2.  Otherwise, all data points are
weighted equally, with a weight of one.  Note that if you don't
specify a [1musing [22moption at all, no y deviations are read from the
datafile even if it does have a third column, so you'll always get
unit weights.

To fit a function with two independent variables, z=f(x,y), the
required format is [1musing [22mwith four items, x:y:z:s.  The complete
format must be given---no default columns are assumed for a missing
token.  Weights for each data point are evaluated from 's' as above.
If error estimates are not available, a constant value can be speci-
fied as a constant expression (see [1mplot datafile using[22m), e.g., [1musing[0m
[1m1:2:3:(1)[22m.

Multiple datasets may be simultaneously fit with functions of one
independent variable by making y a 'pseudo-variable', e.g., the
dataline number, and fitting as two independent variables.  See [1mfit[0m
[1mmulti-branch[22m.

The [1mvia [22mqualifier specifies which parameters are to be adjusted,
either directly, or by referencing a parameter file.











GNUPLOT 4.1                                                       46


Examples:
      f(x) = a*x**2 + b*x + c
      g(x,y) = a*x**2 + b*y**2 + c*x*y
      FIT_LIMIT = 1e-6
      fit f(x) 'measured.dat' via 'start.par'
      fit f(x) 'measured.dat' using 3:($7-5) via 'start.par'
      fit f(x) './data/trash.dat' using 1:2:3 via a, b, c
      fit g(x,y) 'surface.dat' using 1:2:3:(1) via a, b, c

After each iteration step, detailed information about the current
state of the fit is written to the display.  The same information
about the initial and final states is written to a log file,
"fit.log".  This file is always appended to, so as to not lose any
previous fit history;  it should be deleted or renamed as desired.
By using the command [1mset fit logfile[22m, the name of the log file can
be changed.

If gnuplot was built with this option, and you activated it using
[1mset fit errorvariables[22m, the error for each fitted parameter will be
stored in a variable named like the parameter, but with "_err"
appended.  Thus the errors can be used as input for further computa-
tions.

The fit may be interrupted by pressing Ctrl-C (any key but Ctrl-C
under MSDOS and Atari Multitasking Systems).  After the current
iteration completes, you have the option to (1) stop the fit and
accept the current parameter values, (2) continue the fit, (3) exe-
cute a [1mgnuplot [22mcommand as specified by the environment variable
FIT_SCRIPT.  The default for FIT_SCRIPT is [1mreplot[22m, so if you had
previously plotted both the data and the fitting function in one
graph, you can display the current state of the fit.

Once [1mfit [22mhas finished, the [1mupdate [22mcommand may be used to store final
values in a file for subsequent use as a parameter file.   See
[1mupdate [22mfor details.




     [1m29.1.  Adjustable parameters[0m


     There are two ways that [1mvia [22mcan specify the parameters to be
     adjusted, either directly on the command line or indirectly, by
     referencing a parameter file.  The two use different means to
     set initial values.

     Adjustable parameters can be specified by a comma-separated
     list of variable names after the [1mvia [22mkeyword.  Any variable
     that is not already defined is created with an initial value of
     1.0.  However, the fit is more likely to converge rapidly if
     the variables have been previously declared with more appropri-
     ate starting values.










GNUPLOT 4.1                                                       47


     In a parameter file, each parameter to be varied and a corre-
     sponding initial value are specified, one per line, in the form
           varname = value

     Comments, marked by '#', and blank lines are permissible.  The
     special form
           varname = value       # FIXED

     means that the variable is treated as a 'fixed parameter', ini-
     tialized by the parameter file, but not adjusted by [1mfit[22m.  For
     clarity, it may be useful to designate variables as fixed
     parameters so that their values are reported by [1mfit[22m.  The key-
     word [1m# FIXED [22mhas to appear in exactly this form.




     [1m29.2.  Short introduction[0m


     [1mfit [22mis used to find a set of parameters that 'best' fits your
     data to your user-defined function.  The fit is judged on the
     basis of the sum of the squared differences or 'residuals'
     (SSR) between the input data points and the function values,
     evaluated at the same places.  This quantity is often called
     'chisquare' (i.e., the Greek letter chi, to the power of 2).
     The algorithm attempts to minimize SSR, or more precisely,
     WSSR, as the residuals are 'weighted' by the input data errors
     (or 1.0) before being squared; see [1mfit error_estimates [22mfor
     details.

     That's why it is called 'least-squares fitting'.  Let's look at
     an example to see what is meant by 'non-linear', but first we
     had better go over some terms.  Here it is convenient to use z
     as the dependent variable for user-defined functions of either
     one independent variable, z=f(x), or two independent variables,
     z=f(x,y).  A parameter is a user-defined variable that [1mfit [22mwill
     adjust, i.e., an unknown quantity in the function declaration.
     Linearity/non-linearity refers to the relationship of the
     dependent variable, z, to the parameters which [1mfit [22mis adjust-
     ing, not of z to the independent variables, x and/or y.  (To be
     technical, the second {and higher} derivatives of the fitting
     function with respect to the parameters are zero for a linear
     least-squares problem).

     For linear least-squares (LLS), the user-defined function will
     be a sum of simple functions, not involving any parameters,
     each multiplied by one parameter.  NLLS handles more compli-
     cated functions in which parameters can be used in a large num-
     ber of ways.  An example that illustrates the difference
     between linear and nonlinear least-squares is the Fourier
     series.  One member may be written as
          z=a*sin(c*x) + b*cos(c*x).










GNUPLOT 4.1                                                       48


     If a and b are the unknown parameters and c is constant, then
     estimating values of the parameters is a linear least-squares
     problem.  However, if c is an unknown parameter, the problem is
     nonlinear.

     In the linear case, parameter values can be determined by com-
     paratively simple linear algebra, in one direct step.  However
     LLS is a special case which is also solved along with more gen-
     eral NLLS problems by the iterative procedure that [1mgnuplot[0m
     uses.  [1mfit [22mattempts to find the minimum by doing a search.
     Each step (iteration) calculates WSSR with a new set of parame-
     ter values.  The Marquardt-Levenberg algorithm selects the
     parameter values for the next iteration.  The process continues
     until a preset criterion is met, either (1) the fit has "con-
     verged" (the relative change in WSSR is less than FIT_LIMIT),
     or (2) it reaches a preset iteration count limit, FIT_MAXITER
     (see [1mfit control variables[22m).  The fit may also be interrupted
     and subsequently halted from the keyboard (see [1mfit[22m).  The user
     variable FIT_CONVERGED contains 1 if the previous fit command
     terminated due to convergence; it contains 0 if the previous
     fit terminated for any other reason.

     Often the function to be fitted will be based on a model (or
     theory) that attempts to describe or predict the behaviour of
     the data.  Then [1mfit [22mcan be used to find values for the free
     parameters of the model, to determine how well the data fits
     the model, and to estimate an error range for each parameter.
     See [1mfit error_estimates[22m.

     Alternatively, in curve-fitting, functions are selected inde-
     pendent of a model (on the basis of experience as to which are
     likely to describe the trend of the data with the desired reso-
     lution and a minimum number of parameters*functions.)  The [1mfit[0m
     solution then provides an analytic representation of the curve.

     However, if all you really want is a smooth curve through your
     data points, the [1msmooth [22moption to [1mplot [22mmay be what you've been
     looking for rather than [1mfit[22m.



     [1m29.3.  Error estimates[0m


     In [1mfit[22m, the term "error" is used in two different contexts,
     data error estimates and parameter error estimates.

     Data error estimates are used to calculate the relative weight
     of each data point when determining the weighted sum of squared
     residuals, WSSR or chisquare.  They can affect the parameter
     estimates, since they determine how much influence the devia-
     tion of each data point from the fitted function has on the
     final values.  Some of the [1mfit [22moutput information, including










GNUPLOT 4.1                                                       49


     the parameter error estimates, is more meaningful if accurate
     data error estimates have been provided.

     The 'statistical overview' describes some of the [1mfit [22moutput and
     gives some background for the 'practical guidelines'.




          [1m29.3.1.  Statistical overview[0m


          The theory of non-linear least-squares (NLLS) is generally
          described in terms of a normal distribution of errors,
          that is, the input data is assumed to be a sample from a
          population having a given mean and a Gaussian (normal)
          distribution about the mean with a given standard devia-
          tion.  For a sample of sufficiently large size, and know-
          ing the population standard deviation, one can use the
          statistics of the chisquare distribution to describe a
          "goodness of fit" by looking at the variable often called
          "chisquare".  Here, it is sufficient to say that a reduced
          chisquare (chisquare/degrees of freedom, where degrees of
          freedom is the number of datapoints less the number of
          parameters being fitted) of 1.0 is an indication that the
          weighted sum of squared deviations between the fitted
          function and the data points is the same as that expected
          for a random sample from a population characterized by the
          function with the current value of the parameters and the
          given standard deviations.

          If the standard deviation for the population is not con-
          stant, as in counting statistics where variance = counts,
          then each point should be individually weighted when com-
          paring the observed sum of deviations and the expected sum
          of deviations.

          At the conclusion [1mfit [22mreports 'stdfit', the standard devi-
          ation of the fit, which is the rms of the residuals, and
          the variance of the residuals, also called 'reduced
          chisquare' when the data points are weighted.  The number
          of degrees of freedom (the number of data points minus the
          number of fitted parameters) is used in these estimates
          because the parameters used in calculating the residuals
          of the datapoints were obtained from the same data.  These
          values are exported to the variables
                FIT_NDF = Number of degrees of freedom
                FIT_WSSR = Weighted sum-of-squares residual
                FIT_STDFIT = sqrt(WSSR/NDF)

          To estimate confidence levels for the parameters, one can
          use the minimum chisquare obtained from the fit and
          chisquare statistics to determine the value of chisquare










GNUPLOT 4.1                                                       50


          corresponding to the desired confidence level, but consid-
          erably more calculation is required to determine the com-
          binations of parameters which produce such values.

          Rather than determine confidence intervals, [1mfit [22mreports
          parameter error estimates which are readily obtained from
          the variance-covariance matrix after the final iteration.
          By convention, these estimates are called "standard
          errors" or "asymptotic standard errors", since they are
          calculated in the same way as the standard errors (stan-
          dard deviation of each parameter) of a linear least-
          squares problem, even though the statistical conditions
          for designating the quantity calculated to be a standard
          deviation are not generally valid for the NLLS problem.
          The asymptotic standard errors are generally over-opti-
          mistic and should not be used for determining confidence
          levels, but are useful for qualitative purposes.

          The final solution also produces a correlation matrix,
          which gives an indication of the correlation of parameters
          in the region of the solution; if one parameter is
          changed, increasing chisquare, does changing another com-
          pensate?  The main diagonal elements, autocorrelation, are
          all 1; if all parameters were independent, all other ele-
          ments would be nearly 0.  Two variables which completely
          compensate each other would have an off-diagonal element
          of unit magnitude, with a sign depending on whether the
          relation is proportional or inversely proportional.  The
          smaller the magnitudes of the off-diagonal elements, the
          closer the estimates of the standard deviation of each
          parameter would be to the asymptotic standard error.



          [1m29.3.2.  Practical guidelines[0m


          If you have a basis for assigning weights to each data
          point, doing so lets you make use of additional knowledge
          about your measurements, e.g., take into account that some
          points may be more reliable than others.  That may affect
          the final values of the parameters.

          Weighting the data provides a basis for interpreting the
          additional [1mfit [22moutput after the last iteration.  Even if
          you weight each point equally, estimating an average stan-
          dard deviation rather than using a weight of 1 makes WSSR
          a dimensionless variable, as chisquare is by definition.

          Each fit iteration will display information which can be
          used to evaluate the progress of the fit.  (An '*' indi-
          cates that it did not find a smaller WSSR and is trying
          again.)  The 'sum of squares of residuals', also called










GNUPLOT 4.1                                                       51


          'chisquare', is the WSSR between the data and your fitted
          function; [1mfit [22mhas minimized that.  At this stage, with
          weighted data, chisquare is expected to approach the num-
          ber of degrees of freedom (data points minus parameters).
          The WSSR can be used to calculate the reduced chisquare
          (WSSR/ndf) or stdfit, the standard deviation of the fit,
          sqrt(WSSR/ndf).  Both of these are reported for the final
          WSSR.

          If the data are unweighted, stdfit is the rms value of the
          deviation of the data from the fitted function, in user
          units.

          If you supplied valid data errors, the number of data
          points is large enough, and the model is correct, the
          reduced chisquare should be about unity.  (For details,
          look up the 'chi-squared distribution' in your favourite
          statistics reference.)  If so, there are additional tests,
          beyond the scope of this overview, for determining how
          well the model fits the data.

          A reduced chisquare much larger than 1.0 may be due to
          incorrect data error estimates, data errors not normally
          distributed, systematic measurement errors, 'outliers', or
          an incorrect model function.  A plot of the residuals,
          e.g., [1mplot 'datafile' using 1:($2-f($1))[22m, may help to show
          any systematic trends.  Plotting both the data points and
          the function may help to suggest another model.

          Similarly, a reduced chisquare less than 1.0 indicates
          WSSR is less than that expected for a random sample from
          the function with normally distributed errors.  The data
          error estimates may be too large, the statistical assump-
          tions may not be justified, or the model function may be
          too general, fitting fluctuations in a particular sample
          in addition to the underlying trends.  In the latter case,
          a simpler function may be more appropriate.

          You'll have to get used to both [1mfit [22mand the kind of prob-
          lems you apply it to before you can relate the standard
          errors to some more practical estimates of parameter
          uncertainties or evaluate the significance of the correla-
          tion matrix.

          Note that [1mfit[22m, in common with most NLLS implementations,
          minimizes the weighted sum of squared distances (y-
          f(x))**2.  It does not provide any means to account for
          "errors" in the values of x, only in y.  Also, any "out-
          liers" (data points outside the normal distribution of the
          model) will have an exaggerated effect on the solution.













GNUPLOT 4.1                                                       52


     [1m29.4.  Control[0m


     There are a number of [1mgnuplot [22mvariables that can be defined to
     affect [1mfit[22m.  Those which can be defined once [1mgnuplot [22mis running
     are listed under 'control_variables' while those defined before
     starting [1mgnuplot [22mare listed under 'environment_variables'.




          [1m29.4.1.  Control variables[0m


          The default epsilon limit (1e-5) may be changed by declar-
          ing a value for
                FIT_LIMIT
          When the sum of squared residuals changes between two
          iteration steps by a factor less than this number
          (epsilon), the fit is considered to have 'converged'.

          The maximum number of iterations may be limited by declar-
          ing a value for
                FIT_MAXITER
          A value of 0 (or not defining it at all)  means that there
          is no limit.

          If you need even more control about the algorithm, and
          know the Marquardt-Levenberg algorithm well, there are
          some more variables to influence it. The startup value of
          [1mlambda [22mis normally calculated automatically from the ML-
          matrix, but if you want to, you may provide your own one
          with
                FIT_START_LAMBDA
          Specifying FIT_START_LAMBDA as zero or less will re-enable
          the automatic selection. The variable
                FIT_LAMBDA_FACTOR
          gives the factor by which [1mlambda [22mis increased or decreased
          whenever the chi-squared target function increased or
          decreased significantly.  Setting FIT_LAMBDA_FACTOR to
          zero re-enables the default factor of 10.0.

          Other variables with the FIT_ prefix may be added to [1mfit[22m,
          so it is safer not to use that prefix for user-defined
          variables.

          The variables FIT_SKIP and FIT_INDEX were used by earlier
          releases of [1mgnuplot [22mwith a 'fit' patch called [1mgnufit [22mand
          are no longer available.  The datafile [1mevery [22mmodifier pro-
          vides the functionality of FIT_SKIP.  FIT_INDEX was used
          for multi-branch fitting, but multi-branch fitting of one
          independent variable is now done as a pseudo-3D fit in
          which the second independent variable and [1musing [22mare used










GNUPLOT 4.1                                                       53


          to specify the branch.  See [1mfit multi-branch[22m.



          [1m29.4.2.  Environment variables[0m


          The environment variables must be defined before [1mgnuplot[0m
          is executed; how to do so depends on your operating sys-
          tem.

                FIT_LOG
          changes the name (and/or path) of the file to which the
          fit log will be written from the default of "fit.log" in
          the working directory. The default value can be overwrit-
          ten using the command [1mset fit logfile[22m.

                FIT_SCRIPT
          specifies a command that may be executed after an user
          interrupt. The default is [1mreplot[22m, but a [1mplot [22mor [1mload [22mcom-
          mand may be useful to display a plot customized to high-
          light the progress of the fit.



     [1m29.5.  Multi-branch[0m


     In multi-branch fitting, multiple data sets can be simultane-
     ously fit with functions of one independent variable having
     common parameters by minimizing the total WSSR.  The function
     and parameters (branch) for each data set are selected by using
     a 'pseudo-variable', e.g., either the dataline number (a 'col-
     umn' index of -1) or the datafile index (-2), as the second
     independent variable.

     Example:  Given two exponential decays of the form, z=f(x),
     each describing a different data set but having a common decay
     time, estimate the values of the parameters.  If the datafile
     has the format x:z:s, then
          f(x,y) = (y==0) ? a*exp(-x/tau) : b*exp(-x/tau)
          fit f(x,y) 'datafile' using  1:-1:2:3  via a, b, tau

     For a more complicated example, see the file "hexa.fnc" used by
     the "fit.dem" demo.

     Appropriate weighting may be required since unit weights may
     cause one branch to predominate if there is a difference in the
     scale of the dependent variable.  Fitting each branch sepa-
     rately, using the multi-branch solution as initial values, may
     give an indication as to the relative effect of each branch on
     the joint solution.











GNUPLOT 4.1                                                       54


     [1m29.6.  Starting values[0m


     Nonlinear fitting is not guaranteed to converge to the global
     optimum (the solution with the smallest sum of squared residu-
     als, SSR), and can get stuck at a local minimum.  The routine
     has no way to determine that;  it is up to you to judge whether
     this has happened.

     [1mfit [22mmay, and often will get "lost" if started far from a solu-
     tion, where SSR is large and changing slowly as the parameters
     are varied, or it may reach a numerically unstable region
     (e.g., too large a number causing a floating point overflow)
     which results in an "undefined value" message or [1mgnuplot [22mhalt-
     ing.

     To improve the chances of finding the global optimum, you
     should set the starting values at least roughly in the vicinity
     of the solution, e.g., within an order of magnitude, if possi-
     ble.  The closer your starting values are to the solution, the
     less chance of stopping at another minimum.  One way to find
     starting values is to plot data and the fitting function on the
     same graph and change parameter values and [1mreplot [22muntil reason-
     able similarity is reached.  The same plot is also useful to
     check whether the fit stopped at a minimum with a poor fit.

     Of course, a reasonably good fit is not proof there is not a
     "better" fit (in either a statistical sense, characterized by
     an improved goodness-of-fit criterion, or a physical sense,
     with a solution more consistent with the model.)  Depending on
     the problem, it may be desirable to [1mfit [22mwith various sets of
     starting values, covering a reasonable range for each parame-
     ter.



     [1m29.7.  Tips[0m


     Here are some tips to keep in mind to get the most out of [1mfit[22m.
     They're not very organized, so you'll have to read them several
     times until their essence has sunk in.

     The two forms of the [1mvia [22margument to [1mfit [22mserve two largely dis-
     tinct purposes.  The [1mvia "file" [22mform is best used for (possibly
     unattended) batch operation, where you just supply the startup
     values in a file and can later use [1mupdate [22mto copy the results
     back into another (or the same) parameter file.

     The [1mvia var1, var2, ... [22mform is best used interactively, where
     the command history mechanism may be used to edit the list of
     parameters to be fitted or to supply new startup values for the
     next try.  This is particularly useful for hard problems, where










GNUPLOT 4.1                                                       55


     a direct fit to all parameters at once won't work without good
     starting values.  To find such, you can iterate several times,
     fitting only some of the parameters, until the values are close
     enough to the goal that the final fit to all parameters at once
     will work.

     Make sure that there is no mutual dependency among parameters
     of the function you are fitting.  For example, don't try to fit
     a*exp(x+b), because a*exp(x+b)=a*exp(b)*exp(x).  Instead, fit
     either a*exp(x) or exp(x+b).

     A technical issue:  the parameters must not be too different in
     magnitude.  The larger the ratio of the largest and the small-
     est absolute parameter values, the slower the fit will con-
     verge.  If the ratio is close to or above the inverse of the
     machine floating point precision, it may take next to forever
     to converge, or refuse to converge at all.  You will have to
     adapt your function to avoid this, e.g., replace 'parameter' by
     '1e9*parameter' in the function definition, and divide the
     starting value by 1e9.

     If you can write your function as a linear combination of sim-
     ple functions weighted by the parameters to be fitted, by all
     means do so.  That helps a lot, because the problem is no
     longer nonlinear and should converge with only a small number
     of iterations, perhaps just one.

     Some prescriptions for analysing data, given in practical
     experimentation courses, may have you first fit some functions
     to your data, perhaps in a multi-step process of accounting for
     several aspects of the underlying theory one by one, and then
     extract the information you really wanted from the fitting
     parameters of those functions.  With [1mfit[22m, this may often be
     done in one step by writing the model function directly in
     terms of the desired parameters.  Transforming data can also
     quite often be avoided, though sometimes at the cost of a more
     difficult fit problem.  If you think this contradicts the pre-
     vious paragraph about simplifying the fit function, you are
     correct.

     A "singular matrix" message indicates that this implementation
     of the Marquardt-Levenberg algorithm can't calculate parameter
     values for the next iteration.  Try different starting values,
     writing the function in another form, or a simpler function.

     Finally, a nice quote from the manual of another fitting pack-
     age (fudgit), that kind of summarizes all these issues:  "Non-
     linear fitting is an art!"















GNUPLOT 4.1                                                       56


[1m30.  Help[0m


The [1mhelp [22mcommand displays on-line help. To specify information on a
particular topic use the syntax:

      help {<topic>}

If <topic> is not specified, a short message is printed about [1mgnu-[0m
[1mplot[22m.  After help for the requested topic is given, a menu of
subtopics is given; help for a subtopic may be requested by typing
its name, extending the help request.  After that subtopic has been
printed, the request may be extended again or you may go back one
level to the previous topic.  Eventually, the [1mgnuplot [22mcommand line
will return.

If a question mark (?) is given as the topic, the list of topics
currently available is printed on the screen.



[1m31.  History[0m


[1mhistory [22mcommand lists or saves previous entries in the history of
the command line editing, or executes an entry.

Here you find 'usage by examples':

      history               # show the complete history
      history 5             # show last 5 entries in the history
      history quiet 5       # show last 5 entries without entry num-
bers
      history "hist.gp"     # write the complete history to file
hist.gp
      history "hist.gp" append # append the complete history to file
hist.gp
      history 10 "hist.gp"  # write last 10 commands to file hist.gp
      history 10 "|head -5 >>diary.gp" # write 5 history commands
using pipe
      history ?load         # show all history entries starting with
"load"
      history ?"set c"      # like above, several words enclosed in
quotes
      hi !reread            # execute last entry starting with
"reread"
      hist !"set xr"        # like above, several words enclosed in
quotes
      hi !hi                # guess yourself :-))

On systems which support a popen function (Unix), the output of his-
tory can be piped through an external program by starting the file
name with a '|', as one of the above examples demonstrates.










GNUPLOT 4.1                                                       57


[1m32.  If[0m


The [1mif [22mcommand allows commands to be executed conditionally.

Syntax:
      if (<condition>) <command-line> [; else if (<condition>) ...;
else ...]

<condition> will be evaluated.  If it is true (non-zero), then the
command(s) of the <command-line> will be executed.  If <condition>
is false (zero), then the entire <command-line> is ignored until the
next occurrence of [1melse[22m.  Note that use of [1m; [22mto allow multiple com-
mands on the same line will _not_ end the conditionalized commands.

Examples:
      pi=3
      if (pi!=acos(-1)) print "?Fixing pi!"; pi=acos(-1); print pi
will display:
      ?Fixing pi!
      3.14159265358979
but
      if (1==2) print "Never see this"; print "Or this either"
will not display anything.

else:
      v=0
      v=v+1; if (v%2) print "2" ; else if (v%3) print "3"; else
print "fred"
(repeat the last line repeatedly!)

See [1mreread [22mfor an example of how [1mif [22mand [1mreread [22mcan be used together
to perform a loop.



[1m33.  Load[0m


The [1mload [22mcommand executes each line of the specified input file as
if it had been typed in interactively.  Files created by the [1msave[0m
command can later be [1mload[22med.  Any text file containing valid com-
mands can be created and then executed by the [1mload [22mcommand.  Files
being [1mload[22med may themselves contain [1mload [22mor [1mcall [22mcommands.  See [1mcom-[0m
[1mments [22mfor information about comments in commands.  To [1mload [22mwith
arguments, see [1mcall[22m.

The [1mload [22mcommand _must_ be the last command on a multi-command line.

Syntax:
      load "<input-file>"

The name of the input file must be enclosed in quotes.










GNUPLOT 4.1                                                       58


The special filename "-" may be used to [1mload [22mcommands from standard
input.  This allows a [1mgnuplot [22mcommand file to accept some commands
from standard input.  Please see help for [1mbatch/interactive [22mfor more
details.

On some systems which support a popen function (Unix), the load file
can be read from a pipe by starting the file name with a '<'.

Examples:
      load 'work.gnu'
      load "func.dat"
      load "< loadfile_generator.sh"

The [1mload [22mcommand is performed implicitly on any file names given as
arguments to [1mgnuplot[22m.  These are loaded in the order specified, and
then [1mgnuplot [22mexits.



[1m34.  Lower[0m


Syntax:
      lower {plot_window_nb}

The [1mlower [22mcommand lowers (opposite to [1mraise[22m) plot window(s) associ-
ated with the interactive terminal of your gnuplot session, i.e. [1mpm[22m,
[1mwin[22m, [1mwxt [22mor [1mx11[22m. It puts the plot window to bottom in the z-order
windows stack of the window manager of your desktop.

As [1mx11 [22mand [1mwxt [22msupport multiple plot windows, then by default they
lower these windows in descending order of most recently created on
top to the least recently created on bottom. If a plot number is
supplied as an optional parameter, only the associated plot window
will be lowered if it exists.

The optional parameter is ignored for single plot-window terminals,
i.e. [1mpm [22mand [1mwin[22m.



[1m35.  Pause[0m


The [1mpause [22mcommand displays any text associated with the command and
then waits a specified amount of time or until the carriage return
is pressed.  [1mpause [22mis especially useful in conjunction with [1mload[0m
files.

Syntax:
      pause <time> {"<string>"}
      pause mouse {<endcondition>}{, <endcondition>} {"<string>"}











GNUPLOT 4.1                                                       59


<time> may be any constant or expression.  Choosing -1 will wait
until a carriage return is hit, zero (0) won't pause at all, and a
positive number will wait the specified number of seconds.  The time
is rounded to an integer number of seconds if subsecond time resolu-
tion is not supported by the given platform.  [1mpause 0 [22mis synonymous
with [1mprint[22m.

If the current terminal supports mousing, then [1mpause mouse [22mwill ter-
minate on either a mouse click or on ctrl-C.  For all other termi-
nals, or if mousing is not active, [1mpause mouse [22mis equivalent to
[1mpause -1[22m.

If one or more end conditions are given after [1mpause mouse[22m, then any
one of the conditions will terminate the pause. The possible end
conditions are [1mkeypress[22m, [1mbutton1[22m, [1mbutton2[22m, [1mbutton3[22m, and [1many[22m.  If the
pause terminates on a keypress, then the ascii value of the key
pressed is returned in MOUSE_KEY.  The character itself is returned
as a one character string in MOUSE_CHAR.

In all cases the coordinates of the mouse are returned in variables
MOUSE_X, MOUSE_Y, MOUSE_X2, MOUSE_Y2.  See [1mmouse variables[22m.

Note: Since [1mpause [22mcommunicates with the operating system rather than
the graphics, it may behave differently with different device
drivers (depending upon how text and graphics are mixed).

Examples:
      pause -1    # Wait until a carriage return is hit
      pause 3     # Wait three seconds
      pause -1  "Hit return to continue"
      pause 10  "Isn't this pretty?  It's a cubic spline."
      pause mouse "Click any mouse button on selected data point"
      pause mouse keypress "Type a letter from A-F in the active
window"
      pause mouse button1,keypress
      pause mouse any "Any key or button will terminate"

The variant "pause mouse key" will resume after any keypress in the
active plot window. If you want to wait for a particular key to be
pressed, you can use a reread loop such as:

      printf "I will resume after you hit the Tab key in the plot
window"
      load "wait_for_tab"

File "wait_for_tab" contains the lines

      pause mouse key
      if (MOUSE_KEY != 9) reread














GNUPLOT 4.1                                                       60


[1m36.  Plot[0m


[1mplot [22mis the primary command for drawing plots with [1mgnuplot[22m.  It cre-
ates plots of functions and data in many, many ways.  [1mplot [22mis used
to draw 2-d functions and data; [1msplot [22mdraws 2-d projections of 3-d
surfaces and data.  [1mplot [22mand [1msplot [22mcontain many common features; see
[1msplot [22mfor differences.  Note specifically that although the [1mbinary[0m
[1m<binary list> [22mvariation does work for both [1mplot [22mand [1msplot[22m, there are
small differences between these modes.  Furthermore, [1mplot[22m's [1maxes[0m
option does not exist for [1msplot[22m.

Syntax:
      plot {<ranges>}
           {<function> | {"<datafile>" {datafile-modifiers}}}
           {axes <axes>} {<title-spec>} {with <style>}
           {, {definitions,} <function> ...}

where either a <function> or the name of a data file enclosed in
quotes is supplied.  A function is a mathematical expression or a
pair of mathematical expressions in parametric mode.  The expres-
sions may be defined completely or in part earlier in the stream of
[1mgnuplot [22mcommands (see [1muser-defined[22m).

It is also possible to define functions and parameters on the [1mplot[0m
command itself.  This is done merely by isolating them from other
items with commas.

There are four possible sets of axes available; the keyword <axes>
is used to select the axes for which a particular line should be
scaled.  [1mx1y1 [22mrefers to the axes on the bottom and left; [1mx2y2 [22mto
those on the top and right; [1mx1y2 [22mto those on the bottom and right;
and [1mx2y1 [22mto those on the top and left.  Ranges specified on the [1mplot[0m
command apply only to the first set of axes (bottom left).

Examples:
      plot sin(x)
      plot f(x) = sin(x*a), a = .2, f(x), a = .4, f(x)
      plot [t=1:10] [-pi:pi*2] tan(t), \
           "data.1" using (tan($2)):($3/$4) smooth csplines \
                    axes x1y2 notitle with lines 5

See also [1mshow plot[22m.




     [1m36.1.  Data[0m


     Discrete data contained in a file can be displayed by specify-
     ing the name of the data file (enclosed in single or double
     quotes) on the [1mplot [22mcommand line.










GNUPLOT 4.1                                                       61


     Syntax:
           plot '<file_name>' {binary <binary list>}
                              {matrix}
                              {index <index list>}
                              {every <every list>}
                              {thru <thru expression>}
                              {using <using list>}
                              {smooth <option>}

     The modifiers [1mbinary[22m, [1mindex[22m, [1mevery[22m, [1mthru[22m, [1musing[22m, and [1msmooth [22mare
     discussed separately.  In brief, [1mbinary [22mallows data entry from
     a binary file (default is ASCII), [1mindex [22mselects which data sets
     in a multi-data-set file are to be plotted, [1mevery [22mspecifies
     which points within a single data set are to be plotted, [1musing[0m
     determines how the columns within a single record are to be
     interpreted ([1mthru [22mis a special case of [1musing[22m), and [1msmooth[0m
     allows for simple interpolation and approximation.  ([1msplot [22mhas
     a similar syntax, but does not support the [1msmooth [22mand [1mthru[0m
     options.)


     ASCII DATA FILES:

     Data files should contain at least one data point per record
     ([1musing [22mcan select one data point from the record). Records
     beginning with [1m# [22m(and also with [1m! [22mon VMS) will be treated as
     comments and ignored.  Each data point represents an (x,y)
     pair. For [1mplot[22ms with error bars or error bars with lines (see
     [1mset style errorbars [22mor [1mset style errorlines[22m), each data point
     is (x,y,ydelta), (x,y,ylow,yhigh), (x,y,xdelta),
     (x,y,xlow,xhigh), or (x,y,xlow,xhigh,ylow,yhigh).

     In all cases, the numbers of each record of a data file must be
     separated by white space (one or more blanks or tabs) unless a
     format specifier is provided by the [1musing [22moption. This white
     space divides each record into columns. However, whitespace
     inside a pair of double quotes is ignored when counting
     columns, so the following datafile line has three columns:
           1.0 "second column" 3.0

     Data may be written in exponential format with the exponent
     preceded by the letter e, E, d, D, q, or Q.

     Only one column (the y value) need be provided.  If x is omit-
     ted, [1mgnuplot [22mprovides integer values starting at 0.

     In datafiles, blank records (records with no characters other
     than blanks and a newline and/or carriage return) are signifi-
     cant---pairs of blank records separate [1mindex[22mes (see [1mplot[0m
     [1mdatafile index[22m).  Data separated by double blank records are
     treated as if they were in separate data files.

     Single blank records designate discontinuities in a [1mplot[22m; no










GNUPLOT 4.1                                                       62


     line will join points separated by a blank records (if they are
     plotted with a line style).

     If autoscaling has been enabled ([1mset autoscale[22m), the axes are
     automatically extended to include all datapoints, with a whole
     number of tic marks if tics are being drawn.  This has two con-
     sequences: i) For [1msplot[22m, the corner of the surface may not
     coincide with the corner of the base.  In this case, no verti-
     cal line is drawn.  ii) When plotting data with the same x
     range on a dual-axis graph, the x coordinates may not coincide
     if the x2tics are not being drawn.  This is because the x axis
     has been autoextended to a whole number of tics, but the x2
     axis has not.  The following example illustrates the problem:

           reset; plot '-', '-' axes x2y1
           1 1
           19 19
           e
           1 1
           19 19
           e

     To avoid this, you can use the [1mfixmin[22m/[1mfixmax [22mfeature of the [1mset[0m
     [1mautoscale [22mcommand, which turns off the automatic extension of
     the axis range upto the next tic mark.


     BINARY DATA FILES:

     Gnuplot can read binary data files.  However, adequate informa-
     tion about details of the file format must be given on the com-
     mand line or extracted from the file itself for a supported
     binary [1mfiletype[22m.  In particular, there are two structures for
     binary files, a matrix binary format and a general binary for-
     mat.

     The matrix binary format contains a two dimensional array of 32
     bit IEEE float values with an additional column and row of
     coordinate values.  As with ASCII matrix, in the using list,
     repetition of the coordinate row constitutes column 1, repeti-
     tion of the coordinate column constitutes column 2, and the
     array of values constitutes column 3.

     The general binary format contains an arbitrary number of
     columns for which information must be specified at the command
     line.  For example, [1marray[22m, [1mrecord[22m, [1mformat [22mand [1musing [22mcan indi-
     cate the size, format and dimension of data.  There are a vari-
     ety of useful commands for skipping file headers and changing
     endianess.  There are a set of commands for positioning and
     translating data since often coordinates are not part of the
     file when uniform sampling is inherent in the data.  Different
     from matrix binary or ASCII, general binary does not treat the
     generated columns as 1, 2 or 3 in the using list.  Rather,










GNUPLOT 4.1                                                       63


     column 1 begins with column 1 of the file, or as specified in
     the [1mformat [22mlist.

     There are global default settings for the various binary
     options which may be set using the same syntax as the options
     when used as part of the [1m(s)plot <filename> binary ... [22mcommand.
     This syntax is [1mset datafile binary ...[22m.  The general rule is
     that common command-line specified parameters override file-
     extracted parameters which override default parameters.

     Matrix binary is the default binary format when no keywords
     specific to general binary are given, i.e., [1marray[22m, [1mrecord[22m, [1mfor-[0m
     [1mmat[22m, [1mfiletype[22m.

     General binary data can be entered at the command line via the
     special file name '-'.  However, this is intended for use
     through a pipe where programs can exchange binary data, not for
     keyboards.  There is no "end of record" character for binary
     data.  Gnuplot continues reading from a pipe until it has read
     the number of points declared in the [1marray [22mqualifier.

     See [1mdatafile binary [22mfor more details.




          [1m36.1.1.  Binary[0m


          The [1mbinary [22mkeyword allows a data file to be binary as
          opposed to ASCII.  There are two formats for
          binary--matrix binary and general binary.  Matrix binary
          is a fixed format in which data appears in a 2D array with
          an extra row and column for coordinate values.  General
          binary is a flexible format for which details about the
          file must be given at the command line.

          See [1mbinary matrix [22mor [1mbinary general [22mfor more details.



          [1m36.1.2.  Binary general[0m


          General binary data in which format information is not
          necessarily part of the file can be read by giving further
          details about the file format at the command line.
          Although the syntax is slightly arcane to the casual user,
          general binary is particularly useful for application pro-
          grams using gnuplot and sending large amounts of data.

          Syntax:
                plot '<file_name>' {binary <binary list>} ...










GNUPLOT 4.1                                                       64


                splot '<file_name>' {binary <binary list>} ...

          General binary format is activated by keywords in <binary
          list> pertaining to information about file structure,
          i.e., [1marray[22m, [1mrecord[22m, [1mformat [22mor [1mfiletype[22m.  Otherwise,
          matrix binary format is assumed.  (See [1mbinary matrix [22mfor
          more details.)

          There are some standard file types that may be read for
          which details about the binary format may be extracted
          automatically.  (Type [1mshow datafile binary [22mat the command
          line for a list.)  Otherwise, details must be specified at
          the command line or set in the defaults.  Keywords are
          described below.

          The keyword [1mfiletype [22min <binary list> controls the routine
          used to read the file, i.e., the format of the data.  For
          a list of the supported file types, type [1mshow datafile[0m
          [1mbinary filetypes[22m.  If no file type is given, the rule is
          that traditional gnuplot binary is assumed for [1msplot [22mif
          the [1mbinary [22mkeyword stands alone.  In all other circum-
          stances, for [1mplot [22mor when one of the <binary list> key-
          words appears, a raw binary file is assumed whereby the
          keywords specify the binary format.

          General binary data files fall into two basic classes, and
          some files may be of both classes depending upon how they
          are treated.  There is that class for which uniform sam-
          pling is assumed and point coordinates must be generated.
          This is the class for which full control via the <binary
          list> keywords applies.  For this class, the settings
          precedence is that command line parameters override in-
          file parameters, which override default settings.  The
          other class is that set of files for which coordinate
          information is contained within the file or there is pos-
          sibly a non-uniform sampling such as gnuplot binary.

          Other than for the unique data files such as gnuplot
          binary, one should think of binary data as conceptually
          the same as ASCII data.  Each point has columns of infor-
          mation which are selected via the [1m<using list> [22massociated
          with [1musing[22m.  When no [1mformat [22mstring is specified, gnuplot
          will retrieve a number of binary variables equal to the
          largest column given in the [1m<using list>[22m.  For example,
          [1musing 1:3 [22mwill result in three columns being read, of
          which the second will be ignored.  There are default using
          lists based upon the typical number of parameters associ-
          ated with a certain plot type.  For example, [1mwith image[0m
          has a default of [1musing 1[22m, while [1mwith rgbimage [22mhas a
          default of [1musing 1:2:3[22m.  Note that the special characters
          for [1musing [22mrepresenting point/line/index generally should
          not be used for binary data.  There are keywords in
          <binary list> that control this.










GNUPLOT 4.1                                                       65


               [1m36.1.2.1.  Array[0m


               Describes the sampling array dimensions associated
               with the binary file.  The coordinates will be gener-
               ated by gnuplot.  A number must be specified for each
               dimension, thereby calling out the size of the array.
               For example, [1marray=10x20 [22mmeans the underlying sam-
               pling structure is two-dimensional with 10 points
               along the first (x) dimension and 20 points along the
               second (y) dimension.  A special "number", [1mInf[22m, can
               be used to indicate that data should be read until
               the end of file.  A colon can be used to separate the
               dimensions for multiple records.  For example,
               [1marray=25:35 [22mindicates there are two one-dimensional
               records within the file.  The colon behavior applies
               to the remaining keywords in this list for which it
               makes sense to be associated with individual records.

               Currently, syntax allows for up to three-dimensional
               arrays.  However, no conventions have yet been made
               for handling three-dimensional coordinates.



               [1m36.1.2.2.  Record[0m


               This keyword serves the same function as [1marray[22m, hav-
               ing the same syntax.  However, [1mrecord [22mcauses gnuplot
               to not generate coordinate information.  This is for
               the case where such information may be included in
               one of the columns of the binary data file.



               [1m36.1.2.3.  Format[0m


               The default binary format is a float.  For more flex-
               ibility, the format can include details about vari-
               able sizes.  For example, [1mformat="%uchar%int%float"[0m
               associates an unsigned character with the first using
               column, an int with the second column and a float
               with the third column.  If the number of size speci-
               fications is less than the greatest column number,
               the size is implicitly taken to be similar to the
               last given variable size.

               Furthermore, the format specification can include
               "discarded" terms via the [1m* [22mcharacter.  For example,
               to skip the middle column of the previous example,
               one could write [1mformat="%uchar%*int%float" [22mand










GNUPLOT 4.1                                                       66


               gnuplot will discard the middle integer.  To list
               variable sizes, type [1mshow datafile binary datasizes[22m.
               There are a group of names that are machine dependent
               along with their sizes in bytes for the particular
               compilation.  There is also a group of names which
               attempt to be machine independent.



               [1m36.1.2.4.  Endian[0m


               Often the endianess of binary data in the file does
               not agree with the endianess used by the platform on
               which gnuplot is running.  Several words can direct
               gnuplot how to arrange bytes.  For example
               [1mendian=little [22mmeans treat the binary file as having
               byte significance from least to greatest. The options
               are

                             little:  least significant to greatest
               significance
                                big:  greatest significance to least
               significance
                            default:  assume file endianess is the
               same as compiler
                        swap (swab):  Interchange the significance.
               (If things
                                      don't look right, try this.)

               Gnuplot can support "middle" ("pdp") endian if it is
               compiled with that option.



               [1m36.1.2.5.  Filetype[0m


               For some standard binary file formats gnuplot can
               extract all the necessary information from the file
               in question.  As an example, "format=edf" will read
               ESRF Header File format files.  For a list of the
               currently supported file formats, type [1mshow datafile[0m
               [1mbinary filetypes[22m.

               There is a special file type called [1mauto [22mfor which
               gnuplot will check if the binary file's extension is
               a quasi-standard extension for a supported format.

               Command line keywords may be used to override set-
               tings extracted from the file.  The settings from the
               file override any defaults.  (See [1mset datafile binary[0m
               for details.)










GNUPLOT 4.1                                                       67


                    [1m36.1.2.5.1.  Avs[0m


                    [1mavs [22mis one of the automatically recognized
                    binary file types for images.  AVS is an
                    extremely simple format, suitable mostly for
                    streaming between applications. It consists of 2
                    longs (xwidth, ywidth) followed by a stream of
                    pixels, each with four bytes of information
                    alpha/red/green/blue.



                    [1m36.1.2.5.2.  Edf[0m


                    [1medf [22mis one of the automatically recognized
                    binary file types for images.  EDF stands for
                    ESRF Data Format, and it supports both edf and
                    ehf formats (the latter means ESRF Header For-
                    mat).  More information on specifications can be
                    found at

                      http://www.esrf.fr/computing/expg/sub-
                    groups/general/format/Format.html

                    See also [1mbinary[22m.



               [1m36.1.2.6.  Keywords[0m


               The following keywords apply only when generating
               coordinates.  That is, when the keyword [1marray [22mis
               used.




                    [1m36.1.2.6.1.  Scan[0m


                    A great deal of confusion can arise concerning
                    the relationship between how gnuplot scans a
                    binary file and the dimensions seen on the plot.
                    To lessen the confusion, conceptually think of
                    gnuplot _always_ scanning the binary file
                    point/line/plane or fast/medium/slow.  Then this
                    keyword is used to tell gnuplot how to map this
                    scanning convention to the Cartesian convention
                    shown in plots, i.e., x/y/z.  The qualifier for
                    scan is a two or three letter code representing










GNUPLOT 4.1                                                       68


                    where point is assigned (first letter), line is
                    assigned (second letter), and plane is assigned
                    (third letter).  For example, [1mscan=yx [22mmeans the
                    fastest, point-by-point, increment should be
                    mapped along the Cartesian y dimension and the
                    middle, line-by-line, increment should be mapped
                    along the x dimension.

                    When the plotting mode is [1mplot[22m, the qualifier
                    code can include the two letters x and y.  For
                    [1msplot[22m, it can include the three letters x, y and
                    z.

                    There is nothing restricting the inherent map-
                    ping from point/line/plane to apply only to
                    Cartesian coordinates.  For this reason there
                    are cylindrical coordinate synonyms for the
                    qualifier codes where t (theta), r and z are
                    analogous to the x, y and z of Cartesian coordi-
                    nates.



                    [1m36.1.2.6.2.  Transpose[0m


                    Shorthand notation for [1mscan=yx [22mor [1mscan=yxz[22m.



                    [1m36.1.2.6.3.  Dx, dy, dz[0m


                    When gnuplot generates coordinates, it uses the
                    spacing described by these keywords.  For exam-
                    ple [1mdx=10 dy=20 [22mwould mean space samples along
                    the x dimension by 10 and space samples along
                    the y dimension by 20.  [1mdy [22mcannot appear if [1mdx[0m
                    does not appear.  Similarly, [1mdz [22mcannot appear if
                    [1mdy [22mdoes not appear.  If the underlying dimen-
                    sions are greater than the keywords specified,
                    the spacing of the highest dimension given is
                    extended to the other dimensions.  For example,
                    if an image is being read from a file and only
                    [1mdx=3.5 [22mis given gnuplot uses a delta x and delta
                    y of 3.5.

                    The following keywords also apply only when gen-
                    erating coordinates.  However they may also be
                    used with matrix binary files.













GNUPLOT 4.1                                                       69


                    [1m36.1.2.6.4.  Flipx, flipy, flipz[0m


                    Sometimes the scanning directions in a binary
                    datafile are not consistent with that assumed by
                    gnuplot.  These keywords can flip the scanning
                    direction along dimensions x, y, z.



                    [1m36.1.2.6.5.  Origin[0m


                    When gnuplot generates coordinates based upon
                    transposition and flip, it attempts to always
                    position the lower left point in the array at
                    the origin, i.e., the data lies in the first
                    quadrant of a Cartesian system after transpose
                    and flip.

                    To position the array somewhere else on the
                    graph, the [1morigin [22mkeyword directs gnuplot to
                    position the lower left point of the array at a
                    point specified by a tuple.  The tuple should be
                    a double for [1mplot [22mand a triple for [1msplot[22m.  For
                    example, [1morigin=(100,100):(100,200) [22mis for two
                    records in the file and intended for plotting in
                    two dimensions. A second example, [1mori-[0m
                    [1mgin=(0,0,3.5)[22m, is for plotting in three dimen-
                    sions.



                    [1m36.1.2.6.6.  Center[0m


                    Similar to [1morigin[22m, this keyword will position
                    the array such that its center lies at the point
                    given by the tuple.  For example, [1mcenter=(0,0)[22m.
                    Center does not apply when the size of the array
                    is [1mInf[22m.



                    [1m36.1.2.6.7.  Rotate[0m


                    The transpose and flip commands provide some
                    flexibility in generating and orienting coordi-
                    nates.  However, for full degrees of freedom, it
                    is possible to apply a rotational vector
                    described by a rotational angle in two dimen-
                    sions.










GNUPLOT 4.1                                                       70


                    The [1mrotate [22mkeyword applies to the two-dimen-
                    sional plane, whether it be [1mplot [22mor [1msplot[22m.  The
                    rotation is done with respect to the positive
                    angle of the Cartesian plane.

                    The angle can be expressed in radians, radians
                    as a multiple of pi, or degrees.  For example,
                    [1mrotate=1.5708[22m, [1mrotate=0.5pi [22mand [1mrotate=90deg [22mare
                    equivalent.

                    If [1morigin [22mis specified, the rotation is done
                    about the lower left sample point before trans-
                    lation.  Otherwise, the rotation is done about
                    the array [1mcenter[22m.



                    [1m36.1.2.6.8.  Perpendicular[0m


                    For [1msplot[22m, the concept of a rotational vector is
                    implemented by a triple representing the vector
                    to be oriented normal to the two-dimensional x-y
                    plane.  Naturally, the default is (0,0,1).  Thus
                    specifying both rotate and perpendicular
                    together can orient data myriad ways in three-
                    space.

                    The two-dimensional rotation is done first, fol-
                    lowed by the three-dimensional rotation.  That
                    is, if R' is the rotational 2 x 2 matrix
                    described by an angle, and P is the 3 x 3 matrix
                    projecting (0,0,1) to (xp,yp,zp), let R be con-
                    structed from R' at the upper left sub-matrix, 1
                    at element 3,3 and zeros elsewhere.  Then the
                    matrix formula for translating data is v' = P R
                    v, where v is the 3 x 1 vector of data extracted
                    from the data file.  In cases where the data of
                    the file is inherently not three-dimensional,
                    logical rules are used to place the data in
                    three-space.  (E.g., usually setting the z-
                    dimension value to zero and placing 2D data in
                    the x-y plane.)



               [1m36.1.2.7.  Binary examples[0m


               Examples:

                     # Selects two float values (second one
               implicit) with a float value










GNUPLOT 4.1                                                       71


                     # discarded between them for an indefinite
               length of 1D data.
                     plot '<file_name>' binary for-
               mat="%float%*float" using 1:2 with lines

                     # The data file header contains all details
               necessary for creating
                     # coordinates from an EDF file.
                     plot '<file_name>' binary filetype=edf with
               image
                     plot '<file_name>.edf' binary filetype=auto
               with image

                     # Selects three unsigned characters for compo-
               nents of a raw RGB image
                     # and flips the y-dimension so that typical
               image orientation (start
                     # at top left corner) translates to the Carte-
               sian plane.  Pixel
                     # spacing is given and there are two images in
               the file.  One of them
                     # is translated via origin.
                     plot '<file_name>' binary
               array=512x1024:1024x512 format='%uchar' \
                          dx=2:1 dy=1:2 origin=(0,0):(1024,1024)
               flipy u 1:2:3 w rgbimage

                     # Four separate records in which the coordi-
               nates are part of the
                     # data file.  The file was created with a endi-
               aness different from
                     # the system on which gnuplot is running.
                     splot '<file_name>' binary record=30:30:29:26
               endian=swap u 1:2:3

               See also [1mbinary matrix[22m.



          [1m36.1.3.  Every[0m


          The [1mevery [22mkeyword allows a periodic sampling of a data set
          to be plotted.

          In the discussion a "point" is a datum defined by a single
          record in the file; "block" here will mean the same thing
          as "datablock" (see [1mglossary[22m).

          Syntax:
                plot 'file' every {<point_incr>}
                                    {:{<block_incr>}
                                      {:{<start_point>}










GNUPLOT 4.1                                                       72


                                        {:{<start_block>}
                                          {:{<end_point>}
                                            {:<end_block>}}}}}

          The data points to be plotted are selected according to a
          loop from <[1mstart_point[22m> to <[1mend_point[22m> with increment
          <[1mpoint_incr[22m> and the blocks according to a loop from
          <[1mstart_block[22m> to <[1mend_block[22m> with increment <[1mblock_incr[22m>.

          The first datum in each block is numbered '0', as is the
          first block in the file.

          Note that records containing unplottable information are
          counted.

          Any of the numbers can be omitted; the increments default
          to unity, the start values to the first point or block,
          and the end values to the last point or block.  If [1mevery[0m
          is not specified, all points in all lines are plotted.

          Examples:
                every :::3::3    # selects just the fourth block
          ('0' is first)
                every :::::9     # selects the first 10 blocks
                every 2:2        # selects every other point in
          every other block
                every ::5::15    # selects points 5 through 15 in
          each block

          See simple plot demos (simple.dem) , Non-parametric splot
          demos , and Parametric splot demos .



          [1m36.1.4.  Example datafile[0m


          This example plots the data in the file "population.dat"
          and a theoretical curve:

                pop(x) = 103*exp((1965-x)/10)
                plot [1960:1990] 'population.dat', pop(x)

          The file "population.dat" might contain:

                # Gnu population in Antarctica since 1965
                   1965   103
                   1970   55
                   1975   34
                   1980   24
                   1985   10












GNUPLOT 4.1                                                       73


          [1m36.1.5.  Index[0m


          The [1mindex [22mkeyword allows only some of the data sets in a
          multi-data-set file to be plotted.

          Syntax:
                plot 'file' index <m>{{:<n>}:<p>}

          Data sets are separated by pairs of blank records.  [1mindex[0m
          [1m<m> [22mselects only set <m>; [1mindex <m>:<n> [22mselects sets in
          the range <m> to <n>; and [1mindex <m>:<n>:<p> [22mselects
          indices <m>, <m>+<p>, <m>+2<p>, etc., but stopping at <n>.
          Following C indexing, the index 0 is assigned to the first
          data set in the file.  Specifying too large an index
          results in an error message.  If [1mindex [22mis not specified,
          all sets are plotted as a single data set.

          Example:
                plot 'file' index 4:5




          [1m36.1.6.  Smooth[0m


          [1mgnuplot [22mincludes a few general-purpose routines for inter-
          polation and approximation of data; these are grouped
          under the [1msmooth [22moption.  More sophisticated data process-
          ing may be performed by preprocessing the data externally
          or by using [1mfit [22mwith an appropriate model.

          Syntax:
                smooth {unique | frequency | csplines | acsplines |
          bezier | sbezier}

          [1munique [22mand [1mfrequency [22mplot the data after making them mono-
          tonic.  Each of the other routines uses the data to deter-
          mine the coefficients of a continuous curve between the
          endpoints of the data.  This curve is then plotted in the
          same manner as a function, that is, by finding its value
          at uniform intervals along the abscissa (see [1mset samples[22m)
          and connecting these points with straight line segments
          (if a line style is chosen).

          If [1mautoscale [22mis in effect, the ranges will be computed
          such that the plotted curve lies within the borders of the
          graph.

          If [1mautoscale [22mis not in effect, and the smooth option is
          either [1macspline [22mor [1mcspline[22m, the sampling of the generated
          curve is done across the intersection of the x range










GNUPLOT 4.1                                                       74


          covered by the input data and the fixed abscissa range as
          defined by [1mset xrange[22m.

          If too few points are available to allow the selected
          option to be applied, an error message is produced.  The
          minimum number is one for [1munique [22mand [1mfrequency[22m, four for
          [1macsplines[22m, and three for the others.

          The [1msmooth [22moptions have no effect on function plots.




               [1m36.1.6.1.  Acsplines[0m


               The [1macsplines [22moption approximates the data with a
               "natural smoothing spline".  After the data are made
               monotonic in x (see [1msmooth unique[22m), a curve is piece-
               wise constructed from segments of cubic polynomials
               whose coefficients are found by the weighting the
               data points; the weights are taken from the third
               column in the data file.  That default can be modi-
               fied by the third entry in the [1musing [22mlist, e.g.,
                     plot 'data-file' using 1:2:(1.0) smooth
               acsplines

               Qualitatively, the absolute magnitude of the weights
               determines the number of segments used to construct
               the curve.  If the weights are large, the effect of
               each datum is large and the curve approaches that
               produced by connecting consecutive points with natu-
               ral cubic splines.  If the weights are small, the
               curve is composed of fewer segments and thus is
               smoother; the limiting case is the single segment
               produced by a weighted linear least squares fit to
               all the data.  The smoothing weight can be expressed
               in terms of errors as a statistical weight for a
               point divided by a "smoothing factor" for the curve
               so that (standard) errors in the file can be used as
               smoothing weights.

               Example:
                     sw(x,S)=1/(x*x*S)
                     plot 'data_file' using 1:2:(sw($3,100)) smooth
               acsplines



               [1m36.1.6.2.  Bezier[0m













GNUPLOT 4.1                                                       75


               The [1mbezier [22moption approximates the data with a Bezier
               curve of degree n (the number of data points) that
               connects the endpoints.



               [1m36.1.6.3.  Csplines[0m


               The [1mcsplines [22moption connects consecutive points by
               natural cubic splines after rendering the data mono-
               tonic (see [1msmooth unique[22m).



               [1m36.1.6.4.  Sbezier[0m


               The [1msbezier [22moption first renders the data monotonic
               ([1munique[22m) and then applies the [1mbezier [22malgorithm.



               [1m36.1.6.5.  Unique[0m


               The [1munique [22moption makes the data monotonic in x;
               points with the same x-value are replaced by a single
               point having the average y-value.  The resulting
               points are then connected by straight line segments.
               demos



               [1m36.1.6.6.  Frequency[0m


               The [1mfrequency [22moption makes the data monotonic in x;
               points with the same x-value are replaced by a single
               point having the summed y-values.  The resulting
               points are then connected by straight line segments.



          [1m36.1.7.  Special-filenames[0m


          A special filename of [1m'-' [22mspecifies that the data are
          inline; i.e., they follow the command.  Only the data fol-
          low the command; [1mplot [22moptions like filters, titles, and
          line styles remain on the [1mplot [22mcommand line.  This is sim-
          ilar to << in unix shell script, and $DECK in VMS DCL.
          The data are entered as though they are being read from a










GNUPLOT 4.1                                                       76


          file, one data point per record.  The letter "e" at the
          start of the first column terminates data entry.  The
          [1musing [22moption can be applied to these data---using it to
          filter them through a function might make sense, but
          selecting columns probably doesn't!

          [1m'-' [22mis intended for situations where it is useful to have
          data and commands together, e.g., when [1mgnuplot [22mis run as a
          sub-process of some front-end application.  Some of the
          demos, for example, might use this feature.  While [1mplot[0m
          options such as [1mindex [22mand [1mevery [22mare recognized, their use
          forces you to enter data that won't be used.  For example,
          while

                plot '-' index 0, '-' index 1
                2
                4
                6


                10
                12
                14
                e
                2
                4
                6


                10
                12
                14
                e

          does indeed work,

                plot '-', '-'
                2
                4
                6
                e
                10
                12
                14
                e

          is a lot easier to type.

          If you use [1m'-' [22mwith [1mreplot[22m, you may need to enter the data
          more than once (see [1mreplot[22m).

          A blank filename ('') specifies that the previous filename
          should be reused.  This can be useful with things like










GNUPLOT 4.1                                                       77


                plot 'a/very/long/filename' using 1:2, '' using 1:3,
          '' using 1:4

          (If you use both [1m'-' [22mand [1m'' [22mon the same [1mplot [22mcommand,
          you'll need to have two sets of inline data, as in the
          example above.)

          On some computer systems with a popen function (Unix), the
          datafile can be piped through a shell command by starting
          the file name with a '<'.  For example,

                pop(x) = 103*exp(-x/10)
                plot "< awk '{print $1-1965, $2}' population.dat",
          pop(x)

          would plot the same information as the first population
          example but with years since 1965 as the x axis.  If you
          want to execute this example, you have to delete all com-
          ments from the data file above or substitute the following
          command for the first part of the command above (the part
          up to the comma):

                plot "< awk '$0 !~ /^#/ {print $1-1965, $2}' popula-
          tion.dat"

          While this approach is most flexible, it is possible to
          achieve simple filtering with the [1musing [22mor [1mthru [22mkeywords.



          [1m36.1.8.  Thru[0m


          The [1mthru [22mfunction is provided for backward compatibility.

          Syntax:
                plot 'file' thru f(x)

          It is equivalent to:

                plot 'file' using 1:(f($2))

          While the latter appears more complex, it is much more
          flexible.  The more natural

                plot 'file' thru f(y)

          also works (i.e. you can use y as the dummy variable).

          [1mthru [22mis parsed for [1msplot [22mand [1mfit [22mbut has no effect.













GNUPLOT 4.1                                                       78


          [1m36.1.9.  Using[0m


          The most common datafile modifier is [1musing[22m.

          Syntax:
                plot 'file' using {<entry> {:<entry> {:<entry>
          ...}}} {'format'}

          If a format is specified, each datafile record is read
          using the C library's 'scanf' function, with the specified
          format string.  Otherwise the record is read and broken
          into columns at spaces or tabs.  A format cannot be speci-
          fied this way for time-format data (instead use [1mset xdata[0m
          [1mtime[22m).

          The resulting array of data is then sorted into columns
          according to the entries.  Each <entry> may be a simple
          column number, which selects the datum, an expression
          enclosed in parentheses, or empty.  The expression can use
          $1 to access the first item read, $2 for the second item,
          and so on.  It can also use [1mcolumn(x) [22mand [1mvalid(x) [22mwhere x
          is an arbitrary expression resulting in an integer.  [1mcol-[0m
          [1mumn(x) [22mreturns the x'th datum; [1mvalid(x) [22mtests that the
          datum in the x'th column is a valid number.  A column num-
          ber of 0 generates a number increasing (from zero) with
          each point, and is reset upon encountering two blank
          records.  A column number of -1 gives the dataline number,
          which starts at 0, increments at single blank records, and
          is reset at double blank records.  A column number of -2
          gives the index number, which is incremented only when two
          blank records are found.  An empty <entry> will default to
          its order in the list of entries.  For example, [1musing ::4[0m
          is interpreted as [1musing 1:2:4[22m.

          N.B.---the [1mcall [22mcommand also uses $'s as a special charac-
          ter.  See [1mcall [22mfor details about how to include a column
          number in a [1mcall [22margument list.

          If the [1musing [22mlist has but a single entry, that <entry>
          will be used for y and the data point number is used for
          x; for example, "[1mplot 'file' using 1[22m" is identical to
          "[1mplot 'file' using 0:1[22m".  If the [1musing [22mlist has two
          entries, these will be used for x and y.  Additional
          entries are usually errors in x and/or y.  See [1mset style[0m
          for details about plotting styles that make use of error
          information, and [1mfit [22mfor use of error information in curve
          fitting.

          'scanf' accepts several numerical specifications but [1mgnu-[0m
          [1mplot [22mrequires all inputs to be double-precision floating-
          point variables, so "%lf" is essentially the only permis-
          sible specifier.  A format string given by the user must










GNUPLOT 4.1                                                       79


          contain at least one such input specifier, and no more
          than seven of them.  'scanf' expects to see white
          space---a blank, tab ("\t"), newline ("\n"), or formfeed
          ("\f")---between numbers; anything else in the input
          stream must be explicitly skipped.

          Note that the use of "\t", "\n", or "\f" requires use of
          double-quotes rather than single-quotes.

          Examples:

          This creates a plot of the sum of the 2nd and 3rd data
          against the first: The format string specifies comma-
          rather than space-separated columns.  The same result
          could be achieved by specifying [1mset datafile separator[0m
          [1m","[22m.
                plot 'file' using 1:($2+$3) '%lf,%lf,%lf'

          In this example the data are read from the file "MyData"
          using a more complicated format:
                plot 'MyData' using "%*lf%lf%*20[^\n]%lf"

          The meaning of this format is:

                %*lf        ignore a number
                %lf         read a double-precision number (x by
          default)
                %*20[^\n]   ignore 20 non-newline characters
                %lf         read a double-precision number (y by
          default)

          One trick is to use the ternary [1m?: [22moperator to filter
          data:

                plot 'file' using 1:($3>10 ? $2 : 1/0)

          which plots the datum in column two against that in column
          one provided the datum in column three exceeds ten.  [1m1/0[0m
          is undefined; [1mgnuplot [22mquietly ignores undefined points, so
          unsuitable points are suppressed.

          In fact, you can use a constant expression for the column
          number, provided it doesn't start with an opening paren-
          thesis; constructs like [1musing 0+(complicated expression)[0m
          can be used.  The crucial point is that the expression is
          evaluated once if it doesn't start with a left parenthe-
          sis, or once for each data point read if it does.

          If timeseries data are being used, the time can span mul-
          tiple columns.  The starting column should be specified.
          Note that the spaces within the time must be included when
          calculating starting columns for other data.  E.g., if the
          first element on a line is a time with an embedded space,










GNUPLOT 4.1                                                       80


          the y value should be specified as column three.

          It should be noted that [1mplot 'file'[22m, [1mplot 'file' using[0m
          [1m1:2[22m, and [1mplot 'file' using ($1):($2) [22mcan be subtly differ-
          ent: 1) if [1mfile [22mhas some lines with one column and some
          with two, the first will invent x values when they are
          missing, the second will quietly ignore the lines with one
          column, and the third will store an undefined value for
          lines with one point (so that in a plot with lines, no
          line joins points across the bad point); 2) if a line con-
          tains text at the first column, the first will abort the
          plot on an error, but the second and third should quietly
          skip the garbage.

          In fact, it is often possible to plot a file with lots of
          lines of garbage at the top simply by specifying

                plot 'file' using 1:2

          However, if you want to leave text in your data files, it
          is safer to put the comment character (#) in the first
          column of the text lines.  Feeble using demos.

          If gnuplot is built with configuration option --enable-
          datastrings, then additional modifiers to [1musing [22mcan spec-
          ify handling of text fields in the datafile. See [1mdatas-[0m
          [1mtrings[22m, [1musing xticlabels[22m, [1musing title[22m.




               [1m36.1.9.1.  Using title[0m


               If gnuplot is built with configuration option
               --enable-datastrings, then the first entry of a col-
               umn of the input data file can be used as a string to
               provide the plot title in the key box.  The column
               containing specified is independent of the column[s]
               used for the plot itself.

                  plot 'data' using 1:($2/$3) title 2

               In this case the entry in the first row of column 2
               will be used for the key entry of the plot con-
               structed from dividing column 2 by column 3.  The
               entry in the first row of column 3 will be ignored.
















GNUPLOT 4.1                                                       81


               [1m36.1.9.2.  Xticlabels[0m


               If gnuplot is built with configuration option
               --enable-datastrings, then a column of the input data
               file can be used to label axis tic marks.  The format
               of such a plot command is

                 plot 'datafile' using <xcol>:<ycol>:xticla-
               bels(<labelcol>) with <plotstyle>

               Tic labels may be read for any of the plot axes: x x2
               y y2 z.  The [1mticlabels(<labelcol>) [22mspecifiers must
               come after all of the data coordinate specifiers in
               the [1musing [22mportion of the command.  For each data
               point which has a valid set of X,Y[,Z] coordinates,
               the text field found in column <labelcol> is added to
               the list of xtic labels at the same X coordinate as
               the point it belongs to. [1mxticlabels(<labelcol>) [22mmay
               be shortened to [1mxtic(<labelcol>)[22m.

               Example:

                     splot "data" using
               2:4:6:xtic(1):ytic(3):ztic(6)

               In this example the x and y axis tic labels are taken
               from different columns than the x and y coordinate
               values. The z axis tics, however, are generated from
               the z coordinate of the corresponding point.



               [1m36.1.9.3.  X2ticlabels[0m


               See [1mplot using xticlabels[22m.



               [1m36.1.9.4.  Yticlabels[0m


               See [1mplot using xticlabels[22m.



               [1m36.1.9.5.  Y2ticlabels[0m


               See [1mplot using xticlabels[22m.












GNUPLOT 4.1                                                       82


               [1m36.1.9.6.  Zticlabels[0m


               See [1mplot using xticlabels[22m.



     [1m36.2.  Errorbars[0m


     Error bars are supported for 2-d data file plots by reading one
     to four additional columns (or [1musing [22mentries); these additional
     values are used in different ways by the various errorbar
     styles.

     In the default situation, [1mgnuplot [22mexpects to see three, four,
     or six numbers on each line of the data file---either

           (x, y, ydelta),
           (x, y, ylow, yhigh),
           (x, y, xdelta),
           (x, y, xlow, xhigh),
           (x, y, xdelta, ydelta), or
           (x, y, xlow, xhigh, ylow, yhigh).

     The x coordinate must be specified.  The order of the numbers
     must be exactly as given above, though the [1musing [22mqualifier can
     manipulate the order and provide values for missing columns.
     For example,

           plot 'file' with errorbars
           plot 'file' using 1:2:(sqrt($1)) with xerrorbars
           plot 'file' using 1:2:($1-$3):($1+$3):4:5 with xyerror-
     bars

     The last example is for a file containing an unsupported combi-
     nation of relative x and absolute y errors.  The [1musing [22mentry
     generates absolute x min and max from the relative error.

     The y error bar is a vertical line plotted from (x, ylow) to
     (x, yhigh). If ydelta is specified instead of ylow and yhigh,
     ylow = y - ydelta and yhigh = y + ydelta are derived. If there
     are only two numbers on the record, yhigh and ylow are both set
     to y. The x error bar is a horizontal line computed in the same
     fashion. To get lines plotted between the data points, [1mplot [22mthe
     data file twice, once with errorbars and once with lines (but
     remember to use the [1mnotitle [22moption on one to avoid two entries
     in the key). Alternately, use the errorlines command (see
     [1merrorlines[22m).

     The error bars have crossbars at each end unless [1mset bars [22mis
     used (see [1mset bars [22mfor details).











GNUPLOT 4.1                                                       83


     If autoscaling is on, the ranges will be adjusted to include
     the error bars.

     See also errorbar demos.

     See [1mplot using[22m, [1mplot with[22m, and [1mset style [22mfor more information.



     [1m36.3.  Errorlines[0m


     Lines with error bars are supported for 2-d data file plots by
     reading one to four additional columns (or [1musing [22mentries);
     these additional values are used in different ways by the vari-
     ous errorlines styles.

     In the default situation, [1mgnuplot [22mexpects to see three, four,
     or six numbers on each line of the data file---either

           (x, y, ydelta),
           (x, y, ylow, yhigh),
           (x, y, xdelta),
           (x, y, xlow, xhigh),
           (x, y, xdelta, ydelta), or
           (x, y, xlow, xhigh, ylow, yhigh).

     The x coordinate must be specified. The order of the numbers
     must be exactly as given above, though the [1musing [22mqualifier can
     manipulate the order and provide values for missing columns.
     For example,

           plot 'file' with errorlines
           plot 'file' using 1:2:(sqrt($1)) with xerrorlines
           plot 'file' using 1:2:($1-$3):($1+$3):4:5 with xyerror-
     lines

     The last example is for a file containing an unsupported combi-
     nation of relative x and absolute y errors. The [1musing [22mentry
     generates absolute x min and max from the relative error.

     The y error bar is a vertical line plotted from (x, ylow) to
     (x, yhigh). If ydelta is specified instead of ylow and yhigh,
     ylow = y - ydelta and yhigh = y + ydelta are derived. If there
     are only two numbers on the record, yhigh and ylow are both set
     to y. The x error bar is a horizontal line computed in the same
     fashion.

     The error bars have crossbars at each end unless [1mset bars [22mis
     used (see [1mset bars [22mfor details).

     If autoscaling is on, the ranges will be adjusted to include
     the error bars.










GNUPLOT 4.1                                                       84


     See [1mplot using[22m, [1mplot with[22m, and [1mset style [22mfor more information.



     [1m36.4.  Parametric[0m


     When in parametric mode ([1mset parametric[22m) mathematical expres-
     sions must be given in pairs for [1mplot [22mand in triplets for
     [1msplot[22m.

     Examples:
           plot sin(t),t**2
           splot cos(u)*cos(v),cos(u)*sin(v),sin(u)

     Data files are plotted as before, except any preceding paramet-
     ric function must be fully specified before a data file is
     given as a plot.  In other words, the x parametric function
     ([1msin(t) [22mabove) and the y parametric function ([1mt**2 [22mabove) must
     not be interrupted with any modifiers or data functions; doing
     so will generate a syntax error stating that the parametric
     function is not fully specified.

     Other modifiers, such as [1mwith [22mand [1mtitle[22m, may be specified only
     after the parametric function has been completed:

           plot sin(t),t**2 title 'Parametric example' with lines-
     points

     See also Parametric Mode Demos.



     [1m36.5.  Ranges[0m


     The optional ranges specify the region of the graph that will
     be displayed.

     Syntax:
           [{<dummy-var>=}{{<min>}:{<max>}}]
           [{{<min>}:{<max>}}]

     The first form applies to the independent variable ([1mxrange [22mor
     [1mtrange[22m, if in parametric mode).  The second form applies to the
     dependent variable [1myrange [22m(and [1mxrange[22m, too, if in parametric
     mode).  <dummy-var> is a new name for the independent variable.
     (The defaults may be changed with [1mset dummy[22m.)  The optional
     <min> and <max> terms can be constant expressions or *.

     In non-parametric mode, the order in which ranges must be given
     is [1mxrange [22mand [1myrange[22m.











GNUPLOT 4.1                                                       85


     In parametric mode, the order for the [1mplot [22mcommand is [1mtrange[22m,
     [1mxrange[22m, and [1myrange[22m.  The following [1mplot [22mcommand shows setting
     the [1mtrange [22mto [-pi:pi], the [1mxrange [22mto [-1.3:1.3] and the [1myrange[0m
     to [-1:1] for the duration of the graph:

           plot [-pi:pi] [-1.3:1.3] [-1:1] sin(t),t**2

     Note that the x2range and y2range cannot be specified
     here---[1mset x2range [22mand [1mset y2range [22mmust be used.

     Ranges are interpreted in the order listed above for the appro-
     priate mode.  Once all those needed are specified, no further
     ones must be listed, but unneeded ones cannot be skipped---use
     an empty range [1m[] [22mas a placeholder.

     [1m* [22mcan be used to allow autoscaling of either of min and max.
     See also [1mset autoscale[22m.

     Ranges specified on the [1mplot [22mor [1msplot [22mcommand line affect only
     that graph; use the [1mset xrange[22m, [1mset yrange[22m, etc., commands to
     change the default ranges for future graphs.

     With time data, you must provide the range (in the same manner
     as the time appears in the datafile) within quotes.  [1mgnuplot[0m
     uses the [1mtimefmt [22mstring to read the value---see [1mset timefmt[22m.

     Examples:

     This uses the current ranges:
           plot cos(x)

     This sets the x range only:
           plot [-10:30] sin(pi*x)/(pi*x)

     This is the same, but uses t as the dummy-variable:
           plot [t = -10 :30]  sin(pi*t)/(pi*t)

     This sets both the x and y ranges:
           plot [-pi:pi] [-3:3]  tan(x), 1/x

     This sets only the y range, and turns off autoscaling on both
     axes:
           plot [ ] [-2:sin(5)*-8] sin(x)**besj0(x)

     This sets xmax and ymin only:
           plot [:200] [-pi:]  exp(sin(x))

     This sets the x range for a timeseries:
           set timefmt "%d/%m/%y %H:%M"
           plot ["1/6/93 12:00":"5/6/93 12:00"] 'timedata.dat'













GNUPLOT 4.1                                                       86


     [1m36.6.  Title[0m


     A line title for each function and data set appears in the key,
     accompanied by a sample of the line and/or symbol used to rep-
     resent it.  It can be changed by using the [1mtitle [22moption.

     Syntax:
           title "<title>" | notitle ["<ignored title>"]

     where <title> is the new title of the line and must be enclosed
     in quotes.  The quotes will not be shown in the key.  A special
     character may be given as a backslash followed by its octal
     value ("\345").  The tab character "\t" is understood.  Note
     that backslash processing occurs only for strings enclosed in
     double quotes---use single quotes to prevent such processing.
     The newline character "\n" is not processed in key entries in
     either type of string.

     The line title and sample can be omitted from the key by using
     the keyword [1mnotitle[22m.  A null title ([1mtitle ''[22m) is equivalent to
     [1mnotitle[22m.  If only the sample is wanted, use one or more blanks
     ([1mtitle ' '[22m).  If [1mnotitle [22mis followed by a string this string is
     ignored.

     If [1mkey autotitles [22mis set (which is the default) and neither
     [1mtitle [22mnor [1mnotitle [22mare specified the line title is the function
     name or the file name as it appears on the [1mplot [22mcommand.  If it
     is a file name, any datafile modifiers specified will be
     included in the default title.

     The layout of the key itself (position, title justification,
     etc.) can be controlled by [1mset key[22m.  Please see [1mset key [22mfor
     details.

     Examples:

     This plots y=x with the title 'x':
           plot x

     This plots x squared with title "x^2" and file "data.1" with
     title "measured data":
           plot x**2 title "x^2", 'data.1' t "measured data"

     This puts an untitled circular border around a polar graph:
           set polar; plot my_function(t), 1 notitle



     [1m36.7.  With[0m













GNUPLOT 4.1                                                       87


     Functions and data may be displayed in one of a large number of
     styles.  The [1mwith [22mkeyword provides the means of selection.

     Syntax:
           with <style> { {linestyle | ls <line_style>}
                          | {{linetype  | lt <line_type>}
                             {linewidth | lw <line_width>}
                             {linecolor | lc <colorspec>}
                             {pointtype | pt <point_type>}
                             {pointsize | ps <point_size>}
                             {fill | fs <fillstyle>}
                             {nohidden3d}
                             {palette}}
                        }

     where <style> is either [1mlines[22m, [1mpoints[22m, [1mlinespoints[22m, [1mimpulses[22m,
     [1mdots[22m, [1msteps[22m, [1mfsteps[22m, [1mhisteps[22m, [1merrorbars[22m, [1mlabels[22m, [1mxerrorbars[22m,
     [1myerrorbars[22m, [1mxyerrorbars[22m, [1merrorlines[22m, [1mxerrorlines[22m, [1myerrorlines[22m,
     [1mxyerrorlines[22m, [1mboxes[22m, [1mhistograms[22m, [1mfilledcurves[22m, [1mboxerrorbars[22m,
     [1mboxxyerrorbars[22m, [1mfinancebars[22m, [1mcandlesticks[22m, [1mvectors[22m, [1mimage[22m,
     [1mrgbimage [22mor [1mpm3d[22m. Some of these styles require additional
     information.  See [1mplotting styles [22mfor details of each style.
     [1mfill [22mis relevant only to certain 2D plots (currently [1mboxes[0m
     [1mboxxyerrorbars [22mand [1mcandlesticks[22m).  Note that [1mfilledcurves [22mand
     [1mpm3d [22mcan take an additional option not listed above (the latter
     only when used in the [1msplot [22mcommand)---see their help or exam-
     ples below for more details.

     Default styles are chosen with the [1mset style function [22mand [1mset[0m
     [1mstyle data [22mcommands.

     By default, each function and data file will use a different
     line type and point type, up to the maximum number of available
     types.  All terminal drivers support at least six different
     point types, and re-use them, in order, if more are required.
     The LaTeX driver supplies an additional six point types (all
     variants of a circle), and thus will only repeat after 12
     curves are plotted with points.  The PostScript drivers
     ([1mpostscript[22m) supplies a total of 64.

     If you wish to choose the line or point type for a single plot,
     <line_type> and <point_type> may be specified.  These are posi-
     tive integer constants (or expressions) that specify the line
     type and point type to be used for the plot.  Use [1mtest [22mto dis-
     play the types available for your terminal.

     You may also scale the line width and point size for a plot by
     using <line_width> and <point_size>, which are specified rela-
     tive to the default values for each terminal.  The pointsize
     may also be altered globally---see [1mset pointsize [22mfor details.
     But note that both <point_size> as set here and  as set by [1mset[0m
     [1mpointsize [22mmultiply the default point size---their effects are
     not cumulative.  That is, [1mset pointsize 2; plot x w p ps 3 [22mwill










GNUPLOT 4.1                                                       88


     use points three times default size, not six.

     It is also possible to specify [1mpointsize variable [22meither as
     part of a line style or for an individual plot. In this case
     one extra column of input is required, i.e. 3 columns for a 2D
     plot and 4 columns for a 3D splot. The size of each individual
     point is determined by multiplying the global pointsize by the
     value read from the data file.

     If you have defined specific line type/width and point
     type/size combinations with [1mset style line[22m, one of these may be
     selected by setting <line_style> to the index of the desired
     style.

     If gnuplot was built with [1mpm3d [22msupport, the special keyword
     [1mpalette [22mis allowed for smooth color change of lines, points and
     dots in [1msplots[22m. The color is chosen from a smooth palette which
     was set previously with the command [1mset palette[22m. The color
     value corresponds to the z-value of the point coordinates or to
     the color coordinate if specified by the 4th parameter in
     [1musing[22m. Both 2d and 3d plots ([1mplot [22mand [1msplot [22mcommands) can use
     palette colors as specified by either their fractional value or
     the corresponding value mapped to the colorbox range. 2d plots
     can not use palette colors mapped by Z value. See [1mcolors[22m, [1mset[0m
     [1mpalette[22m, [1mlinetype[22m.

     The keyword [1mnohidden3d [22mapplies only to plots made with the
     [1msplot [22mcommand.  Normally the global option [1mset hidden3d [22mapplies
     to all plots in the graph.  You can attach the [1mnohidden3d[0m
     option to any individual plots that you want to exclude from
     the hidden3d processing.  The individual elements (lines, dots,
     labels, ...) of a plot marked [1mnohidden3d [22mwill all be drawn,
     even if they would normally be obscured by the elements of some
     other plot.

     The keywords may be abbreviated as indicated.

     Note that the [1mlinewidth[22m, [1mpointsize [22mand [1mpalette [22moptions are not
     supported by all terminals.

     Examples:

     This plots sin(x) with impulses:
           plot sin(x) with impulses

     This plots x with points, x**2 with the default:
           plot x w points, x**2

     This plots tan(x) with the default function style, file
     "data.1" with lines:
           plot [ ] [-2:5] tan(x), 'data.1' with l

     This plots "leastsq.dat" with impulses:










GNUPLOT 4.1                                                       89


           plot 'leastsq.dat' w i

     This plots the data file "population" with boxes:
           plot 'population' with boxes

     This plots "exper.dat" with errorbars and lines connecting the
     points (errorbars require three or four columns):
           plot 'exper.dat' w lines, 'exper.dat' notitle w errorbars

     Another way to plot "exper.dat" with errorlines (errorbars
     require three or four columns):
           plot 'exper.dat' w errorlines

     This plots sin(x) and cos(x) with linespoints, using the same
     line type but different point types:
           plot sin(x) with linesp lt 1 pt 3, cos(x) with linesp lt
     1 pt 4

     This plots file "data" with points of type 3 and twice usual
     size:
           plot 'data' with points pointtype 3 pointsize 2

     This plots file "data" with variable pointsize read from column
     4
           plot 'data' using 1:2:4 with points pt 5 pointsize vari-
     able

     This plots two data sets with lines differing only by weight:
           plot 'd1' t "good" w l lt 2 lw 3, 'd2' t "bad" w l lt 2
     lw 1

     This plots filled curve of x*x and a color stripe:
           plot x*x with filledcurve closed, 40 with filledcurve
     y1=10

     This plots x*x and a color box:
           plot x*x, (x>=-5 && x<=5 ? 40 : 1/0) with filledcurve
     y1=10 lt 8

     This plots a surface with color lines:
           splot x*x-y*y with line palette

     This plots two color surfaces at different altitudes:
           splot x*x-y*y with pm3d, x*x+y*y with pm3d at t




[1m37.  Print[0m


The [1mprint [22mcommand prints the value of <expression> to the screen.
It is synonymous with [1mpause 0[22m.  <expression> may be anything that










GNUPLOT 4.1                                                       90


[1mgnuplot [22mcan evaluate that produces a number, or it can be a string.

Syntax:
      print <expression> {, <expression>, ...}

See [1mexpressions[22m.  The output file can be set with [1mset print[22m.



[1m38.  Pwd[0m


The [1mpwd [22mcommand prints the name of the working directory to the
screen.



[1m39.  Quit[0m


The [1mexit [22mand [1mquit [22mcommands and END-OF-FILE character will exit [1mgnu-[0m
[1mplot[22m.  Each of these commands will clear the output device (as does
the [1mclear [22mcommand) before exiting.



[1m40.  Raise[0m


Syntax:
      raise {plot_window_nb}

The [1mraise [22mcommand raises (opposite to [1mlower[22m) plot window(s) associ-
ated with the interactive terminal of your gnuplot session, i.e. [1mpm[22m,
[1mwin[22m, [1mwxt [22mor [1mx11[22m. It puts the plot window to front (top) in the z-
order windows stack of the window manager of your desktop.

As [1mx11 [22mand [1mwxt [22msupport multiple plot windows, then by default they
raise these windows in descending order of most recently created on
top to the least recently created on bottom. If a plot number is
supplied as an optional parameter, only the associated plot window
will be raised if it exists.

The optional parameter is ignored for single plot-windows terminal,
i.e. [1mpm [22mand [1mwin[22m.

 If the window is not raised under X11, then (1) they don't run in
the same
 X11 session (telnet or ssh session, for example), or (2) raising is
blocked
 by your window manager. On KDE, you may like to go to the KDE Con-
trol Center
 => Desktop => Window Behaviour => Advanced and set the "Focus










GNUPLOT 4.1                                                       91


stealing
 prevention level" to None (default is Low).



[1m41.  Replot[0m


The [1mreplot [22mcommand without arguments repeats the last [1mplot [22mor [1msplot[0m
command.  This can be useful for viewing a plot with different [1mset[0m
options, or when generating the same plot for several devices.

Arguments specified after a [1mreplot [22mcommand will be added onto the
last [1mplot [22mor [1msplot [22mcommand (with an implied ',' separator) before it
is repeated.  [1mreplot [22maccepts the same arguments as the [1mplot [22mand
[1msplot [22mcommands except that ranges cannot be specified.  Thus you can
use [1mreplot [22mto plot a function against the second axes if the previ-
ous command was [1mplot [22mbut not if it was [1msplot[22m.

N.B.---use of

      plot '-' ; ... ; replot

is not recommended.  [1mgnuplot [22mdoes not store the inline data inter-
nally, so since [1mreplot [22mappends new information to the previous [1mplot[0m
and then executes the modified command, the [1m'-' [22mfrom the initial
[1mplot [22mwill expect to read inline data again.

Note that [1mreplot [22mdoes not work in [1mmultiplot [22mmode, since it repro-
duces only the last plot rather than the entire screen.

See also [1mcommand-line-editing [22mfor ways to edit the last [1mplot [22m([1msplot[22m)
command.

See also [1mshow plot [22mto show the whole current plotting command, and
the possibility to copy it into the [1mhistory[22m.



[1m42.  Reread[0m


The [1mreread [22mcommand causes the current [1mgnuplot [22mcommand file, as spec-
ified by a [1mload [22mcommand or on the command line, to be reset to its
starting point before further commands are read from it.  This
essentially implements an endless loop of the commands from the
beginning of the command file to the [1mreread [22mcommand.  (But this is
not necessarily a disaster---[1mreread [22mcan be very useful when used in
conjunction with [1mif[22m.  See [1mif [22mfor details.)  The [1mreread [22mcommand has
no effect if input from standard input.

Examples:











GNUPLOT 4.1                                                       92


Suppose the file "looper" contains the commands
      a=a+1
      plot sin(x*a)
      pause -1
      if(a<5) reread
and from within [1mgnuplot [22myou submit the commands
      a=0
      load 'looper'
The result will be four plots (separated by the [1mpause [22mmessage).

Suppose the file "data" contains six columns of numbers with a total
yrange from 0 to 10; the first is x and the next are five different
functions of x.  Suppose also that the file "plotter" contains the
commands
      c_p = c_p+1
      plot "$0" using 1:c_p with lines linetype c_p
      if(c_p <  n_p) reread
and from within [1mgnuplot [22myou submit the commands
      n_p=6
      c_p=1
      unset key
      set yrange [0:10]
      set multiplot
      call 'plotter' 'data'
      unset multiplot
The result is a single graph consisting of five plots.  The yrange
must be set explicitly to guarantee that the five separate graphs
(drawn on top of each other in multiplot mode) will have exactly the
same axes.  The linetype must be specified; otherwise all the plots
would be drawn with the same type.  See animate.dem in demo direc-
tory for an animated example.




[1m43.  Reset[0m


The [1mreset [22mcommand causes all graph-related options that can be set
with the [1mset [22mcommand to take on their default values.  This command
is useful, e.g., to restore the default graph settings at the end of
a command file, or to return to a defined state after lots of set-
tings have been changed within a command file.  Please refer to the
[1mset [22mcommand to see the default values that the various options take.

The following [1mset [22mcommands do not change the graph status and are
thus left unchanged: the terminal set with [1mset term[22m, the output file
set with [1mset output [22mand directory paths set with [1mset loadpath [22mand
[1mset fontpath[22m.














GNUPLOT 4.1                                                       93


[1m44.  Save[0m


The [1msave [22mcommand saves user-defined functions, variables, the [1mset[0m
[1mterm [22mstatus, all [1mset [22moptions, or all of these, plus the last [1mplot[0m
([1msplot[22m) command to the specified file.

Syntax:
      save  {<option>} '<filename>'

where <option> is [1mfunctions[22m, [1mvariables[22m, [1mterminal [22mor [1mset[22m. If no
option is used, [1mgnuplot [22msaves functions, variables, [1mset [22moptions and
the last [1mplot [22m([1msplot[22m) command.

[1msave[22md files are written in text format and may be read by the [1mload[0m
command. For [1msave [22mwith the [1mset [22moption or without any option, the
[1mterminal [22mchoice and the [1moutput [22mfilename are written out as a com-
ment, to get an output file that works in other installations of
gnuplot, without changes and without risk of unwillingly overwriting
files.

[1msave terminal [22mwill write out just the [1mterminal [22mstatus, without the
comment marker in front of it. This is mainly useful for switching
the [1mterminal [22msetting for a short while, and getting back to the pre-
viously set terminal, afterwards, by loading the saved [1mterminal [22msta-
tus. Note that for a single gnuplot session you may rather use the
other method of saving and restoring current terminal by the com-
mands [1mset term push [22mand [1mset term pop[22m, see [1mset term[22m.

The filename must be enclosed in quotes.

The special filename "-" may be used to [1msave [22mcommands to standard
output.  On systems which support a popen function (Unix), the out-
put of save can be piped through an external program by starting the
file name with a '|'.  This provides a consistent interface to [1mgnu-[0m
[1mplot[22m's internal settings to programs which communicate with [1mgnuplot[0m
through a pipe.  Please see help for [1mbatch/interactive [22mfor more
details.

Examples:
      save 'work.gnu'
      save functions 'func.dat'
      save var 'var.dat'
      save set 'options.dat'
      save term 'myterm.gnu'
      save '-'
      save '|grep title >t.gp'
















GNUPLOT 4.1                                                       94


[1m45.  Set-show[0m


The [1mset [22mcommand can be used to set _lots_ of options.  No screen is
drawn, however, until a [1mplot[22m, [1msplot[22m, or [1mreplot [22mcommand is given.

The [1mshow [22mcommand shows their settings;  [1mshow all [22mshows all the set-
tings.

Options changed using [1mset [22mcan be returned to the default state by
giving the corresponding [1munset [22mcommand.  See also the [1mreset [22mcommand,
which returns all settable parameters to default values.

If a variable contains time/date data, [1mshow [22mwill display it accord-
ing to the format currently defined by [1mset timefmt[22m, even if that was
not in effect when the variable was initially defined.




     [1m45.1.  Angles[0m


     By default, [1mgnuplot [22massumes the independent variable in polar
     graphs is in units of radians.  If [1mset angles degrees [22mis speci-
     fied before [1mset polar[22m, then the default range is [0:360] and
     the independent variable has units of degrees.  This is partic-
     ularly useful for plots of data files.  The angle setting also
     applies to 3-d mapping as set via the [1mset mapping [22mcommand.

     Syntax:
           set angles {degrees | radians}
           show angles

     The angle specified in [1mset grid polar [22mis also read and dis-
     played in the units specified by [1mset angles[22m.

     [1mset angles [22malso affects the arguments of the machine-defined
     functions sin(x), cos(x) and tan(x), and the outputs of
     asin(x), acos(x), atan(x), atan2(x), and arg(x).  It has no
     effect on the arguments of hyperbolic functions or Bessel func-
     tions.  However, the output arguments of inverse hyperbolic
     functions of complex arguments are affected; if these functions
     are used, [1mset angles radians [22mmust be in effect to maintain con-
     sistency between input and output arguments.

           x={1.0,0.1}
           set angles radians
           y=sinh(x)
           print y         #prints {1.16933, 0.154051}
           print asinh(y)  #prints {1.0, 0.1}
     but
           set angles degrees










GNUPLOT 4.1                                                       95


           y=sinh(x)
           print y         #prints {1.16933, 0.154051}
           print asinh(y)  #prints {57.29578, 5.729578}
     See also poldat.dem: polar plot using [1mset angles [22mdemo.



     [1m45.2.  Arrow[0m


     Arbitrary arrows can be placed on a plot using the [1mset arrow[0m
     command.

     Syntax:
           set arrow {<tag>} {from <position>} {to|rto <position>}
                     { {arrowstyle | as <arrow_style>}
                       | { {nohead | head | backhead | heads}
                           {size <length>,<angle>{,<backangle>}}
                           {filled | empty | nofilled}
                           {front | back}
                           { {linestyle | ls <line_style>}
                             | {linetype | lt <line_type>}
                               {linewidth | lw <line_width} } } }

           unset arrow {<tag>}
           show arrow {<tag>}

     <tag> is an integer that identifies the arrow.  If no tag is
     given, the lowest unused tag value is assigned automatically.
     The tag can be used to delete or change a specific arrow.  To
     change any attribute of an existing arrow, use the [1mset arrow[0m
     command with the appropriate tag and specify the parts of the
     arrow to be changed.

     The <position>s are specified by either x,y or x,y,z, and may
     be preceded by [1mfirst[22m, [1msecond[22m, [1mgraph[22m, [1mscreen[22m, or [1mcharacter [22mto
     select the coordinate system.  Unspecified coordinates default
     to 0.  The end points can be specified in one of five coordi-
     nate systems---[1mfirst [22mor [1msecond [22maxes, [1mgraph[22m, [1mscreen[22m, or [1mcharac-[0m
     [1mter[22m.  See [1mcoordinates [22mfor details.  A coordinate system speci-
     fier does not carry over from the "from" position to the "to"
     position.  Arrows outside the screen boundaries are permitted
     but may cause device errors.  If the end point is specified by
     "rto" instead of "to" it is drawn relatively to the start
     point.  For linear axes, [1mgraph [22mand [1mscreen [22mcoordinates, the dis-
     tance between the start and the end point corresponds to the
     given relative coordinate.  For logarithmic axes, the relative
     given coordinate corresponds to the factor of the coordinate
     between start and end point.  Thus, a negative relative value
     or zero are not allowed for logarithmic axes.

     Specifying [1mnohead [22mproduces an arrow drawn without a head---a
     line segment.  This gives you yet another way to draw a line










GNUPLOT 4.1                                                       96


     segment on the plot.  By default, an arrow has a head at its
     end. Specifying [1mbackhead [22mdraws an arrow head at the start point
     of the arrow while [1mheads [22mdraws arrow heads on both ends of the
     line.  Not all terminal types support double-ended arrows.

     Head size can be controlled by [1msize <length>,<angle> [22mor [1msize[0m
     [1m<length>,<angle>,<backangle>[22m, where [1m<length> [22mdefines length of
     each branch of the arrow head and [1m<angle> [22mthe angle (in
     degrees) they make with the arrow.  [1m<Length> [22mis in x-axis
     units; this can be changed by [1mfirst[22m, [1msecond[22m, [1mgraph[22m, [1mscreen[22m, or
     [1mcharacter [22mbefore the <length>;  see [1mcoordinates [22mfor details.
     [1m<Backangle> [22monly takes effect when [1mfilled [22mor [1mempty [22mis also
     used.  Then, [1m<backangle> [22mis the angle (in degrees) the back
     branches make with the arrow (in the same direction as
     [1m<angle>[22m).  The [1mfig [22mterminal has a restricted backangle func-
     tion. It supports three different angles. There are two thresh-
     olds: Below 70 degrees, the arrow head gets an indented back
     angle. Above 110 degrees, the arrow head has an acute back
     angle. Between these thresholds, the back line is straight.

     Specifying [1mfilled [22mproduces filled arrow heads (if heads are
     used).  Filling is supported on filled-polygon capable termi-
     nals, see help of [1mpm3d [22mfor their list, otherwise the arrow
     heads are closed but not filled.  The same result (closed but
     not filled arrow head) is reached by specifying [1mempty[22m.  Fur-
     ther, filling and outline is obviously not supported on termi-
     nals drawing arrows by their own specific routines, like [1mmeta-[0m
     [1mfont[22m, [1mmetapost[22m, [1mlatex [22mor [1mtgif[22m.

     The line style may be selected from a user-defined list of line
     styles (see [1mset style line[22m) or may be defined here by providing
     values for <line_type> (an index from the default list of
     styles) and/or <line_width> (which is a  multiplier for the
     default width).

     Note, however, that if a user-defined line style has been
     selected, its properties (type and width) cannot be altered
     merely by issuing another [1mset arrow [22mcommand with the appropri-
     ate index and [1mlt [22mor [1mlw[22m.

     If [1mfront [22mis given, the arrow is written on top of the graphed
     data. If [1mback [22mis given (the default), the arrow is written
     underneath the graphed data.  Using [1mfront [22mwill prevent an arrow
     from being obscured by dense data.

     Examples:

     To set an arrow pointing from the origin to (1,2) with user-
     defined style 5, use:
           set arrow to 1,2 ls 5

     To set an arrow from bottom left of plotting area to (-5,5,3),
     and tag the arrow number 3, use:










GNUPLOT 4.1                                                       97


           set arrow 3 from graph 0,0 to -5,5,3

     To change the preceding arrow to end at 1,1,1, without an arrow
     head and double its width, use:
           set arrow 3 to 1,1,1 nohead lw 2

     To draw a vertical line from the bottom to the top of the graph
     at x=3, use:
           set arrow from 3, graph 0 to 3, graph 1 nohead

     To draw a vertical arrow with T-shape ends, use:
           set arrow 3 from 0,-5 to 0,5 heads size screen 0.1,90

     To draw an arrow relatively to the start point, where the rela-
     tive distances are given in graph coordinates, use:
           set arrow from 0,-5 rto graph 0.1,0.1

     To draw an arrow with relative end point in logarithmic x axis,
     use:
           set logscale x
           set arrow from 100,-5 rto 10,10
     This draws an arrow from 100,-5 to 1000,5. For the logarithmic
     x axis, the relative coordinate 10 means "factor 10" while for
     the linear y axis, the relative coordinate 10 means "difference
     10".

     To delete arrow number 2, use:
           unset arrow 2

     To delete all arrows, use:
           unset arrow

     To show all arrows (in tag order), use:
           show arrow

     arrows demos.




     [1m45.3.  Autoscale[0m


     Autoscaling may be set individually on the x, y or z axis or
     globally on all axes. The default is to autoscale all axes.

     Syntax:
           set autoscale {<axes>{|min|max|fixmin|fixmax|fix} | fix |
     keepfix}
           unset autoscale {<axes>}
           show autoscale

     where <axes> is either [1mx[22m, [1my[22m, [1mz[22m, [1mcb[22m, [1mx2[22m, [1my2 [22mor [1mxy[22m.  A keyword










GNUPLOT 4.1                                                       98


     with [1mmin [22mor [1mmax [22mappended (this cannot be done with [1mxy[22m) tells
     [1mgnuplot [22mto autoscale just the minimum or maximum of that axis.
     If no keyword is given, all axes are autoscaled.

     A keyword with [1mfixmin[22m, [1mfixmax [22mor [1mfix [22mappended tells gnuplot to
     disable extension of the axis range to the next tic mark posi-
     tion, for autoscaled axes using equidistant tics; [1mset autoscale[0m
     [1mfix [22msets this for all axes.  Command [1mset autoscale keepfix[0m
     autoscales all axes while keeping the fix settings.

     When autoscaling, the axis range is automatically computed and
     the dependent axis (y for a [1mplot [22mand z for [1msplot[22m) is scaled to
     include the range of the function or data being plotted.

     If autoscaling of the dependent axis (y or z) is not set, the
     current y or z range is used.

     Autoscaling the independent variables (x for [1mplot [22mand x,y for
     [1msplot[22m) is a request to set the domain to match any data file
     being plotted.  If there are no data files, autoscaling an
     independent variable has no effect.  In other words, in the
     absence of a data file, functions alone do not affect the x
     range (or the y range if plotting z = f(x,y)).

     Please see [1mset xrange [22mfor additional information about ranges.

     The behavior of autoscaling remains consistent in parametric
     mode, (see [1mset parametric[22m).  However, there are more dependent
     variables and hence more control over x, y, and z axis scales.
     In parametric mode, the independent or dummy variable is t for
     [1mplot[22ms and u,v for [1msplot[22ms.  [1mautoscale [22min parametric mode, then,
     controls all ranges (t, u, v, x, y, and z) and allows x, y, and
     z to be fully autoscaled.

     Autoscaling works the same way for polar mode as it does for
     parametric mode for [1mplot[22m, with the extension that in polar mode
     [1mset dummy [22mcan be used to change the independent variable from t
     (see [1mset dummy[22m).

     When tics are displayed on second axes but no plot has been
     specified for those axes, x2range and y2range are inherited
     from xrange and yrange.  This is done _before_ xrange and
     yrange are autoextended to a whole number of tics, which can
     cause unexpected results.  You can use the [1mfixmin [22mor [1mfixmax[0m
     options to avoid this.

     Examples:

     This sets autoscaling of the y axis (other axes are not
     affected):
           set autoscale y

     This sets autoscaling only for the minimum of the y axis (the










GNUPLOT 4.1                                                       99


     maximum of the y axis and the other axes are not affected):
           set autoscale ymin

     This disables extension of the x2 axis tics to the next tic
     mark, thus keeping the exact range as found in the plotted data
     and functions:
           set autoscale x2fixmin
           set autoscale x2fixmax

     This sets autoscaling of the x and y axes:
           set autoscale xy

     This sets autoscaling of the x, y, z, x2 and y2 axes:
           set autoscale

     This disables autoscaling of the x, y, z, x2 and y2 axes:
           unset autoscale

     This disables autoscaling of the z axis only:
           unset autoscale z




          [1m45.3.1.  Parametric mode[0m


          When in parametric mode ([1mset parametric[22m), the xrange is as
          fully scalable as the y range.  In other words, in para-
          metric mode the x axis can be automatically scaled to fit
          the range of the parametric function that is being plot-
          ted.  Of course, the y axis can also be automatically
          scaled just as in the non-parametric case.  If autoscaling
          on the x axis is not set, the current x range is used.

          Data files are plotted the same in parametric and non-
          parametric mode.  However, there is a difference in mixed
          function and data plots: in non-parametric mode with
          autoscaled x, the x range of the datafile controls the x
          range of the functions; in parametric mode it has no
          influence.

          For completeness a last command [1mset autoscale t [22mis
          accepted.  However, the effect of this "scaling" is very
          minor.  When [1mgnuplot [22mdetermines that the t range would be
          empty, it makes a small adjustment if autoscaling is true.
          Otherwise, [1mgnuplot [22mgives an error.  Such behavior may, in
          fact, not be very useful and the command [1mset autoscale t[0m
          is certainly questionable.

          [1msplot [22mextends the above ideas as you would expect.  If
          autoscaling is set, then x, y, and z ranges are computed
          and each axis scaled to fit the resulting data.










GNUPLOT 4.1                                                      100


          [1m45.3.2.  Polar mode[0m


          When in polar mode ([1mset polar[22m), the xrange and the yrange
          are both found from the polar coordinates, and thus they
          can both be automatically scaled.  In other words, in
          polar mode both the x and y axes can be automatically
          scaled to fit the ranges of the polar function that is
          being plotted.

          When plotting functions in polar mode, the rrange may be
          autoscaled.  When plotting data files in polar mode, the
          trange may also be autoscaled.  Note that if the trange is
          contained within one quadrant, autoscaling will produce a
          polar plot of only that single quadrant.

          Explicitly setting one or two ranges but not others may
          lead to unexpected results.  See also polar demos.



     [1m45.4.  Bars[0m


     The [1mset bars [22mcommand controls the tics at the ends of error
     bars, and also the width of the boxes in plot styles candle-
     sticks and financebars.

     Syntax:
           set bars {small | large | fullwidth | <size>}
           unset bars
           show bars

     [1msmall [22mis a synonym for 0.0, and [1mlarge [22mfor 1.0.  The default is
     1.0 if no size is given.

     The keyword [1mfullwidth [22mis relevant only to histograms with
     errorbars.  It sets the width of the errorbar ends to be the
     same as the width of the associated box in the histogram.  It
     does not change the width of the box itself.



     [1m45.5.  Bmargin[0m


     The command [1mset bmargin [22msets the size of the bottom margin.
     Please see [1mset margin [22mfor details.















GNUPLOT 4.1                                                      101


     [1m45.6.  Border[0m


     The [1mset border [22mand [1munset border [22mcommands control the display of
     the graph borders for the [1mplot [22mand [1msplot [22mcommands.  Note that
     the borders do not necessarily coincide with the axes; with
     [1mplot [22mthey often do, but with [1msplot [22mthey usually do not.

     Syntax:
           set border {<integer>} {front | back} {linewidth | lw
     <line_width>}
                      {{linestyle | ls <line_style>} | {linetype |
     lt <line_type>}}
           unset border
           show border

     With a [1msplot [22mdisplayed in an arbitrary orientation, like [1mset[0m
     [1mview 56,103[22m, the four corners of the x-y plane can be referred
     to as "front", "back", "left" and "right".  A similar set of
     four corners exist for the top surface, of course.  Thus the
     border connecting, say, the back and right corners of the x-y
     plane is the "bottom right back" border, and the border con-
     necting the top and bottom front corners is the "front verti-
     cal".  (This nomenclature is defined solely to allow the reader
     to figure out the table that follows.)

     The borders are encoded in a 12-bit integer: the bottom four
     bits control the border for [1mplot [22mand the sides of the base for
     [1msplot[22m; the next four bits control the verticals in [1msplot[22m; the
     top four bits control the edges on top of the [1msplot[22m.  In
     detail, [1m<integer> [22mshould be the sum of the appropriate entries
     from the following table:




              +--------------------------------------+
              |Bit      plot            splot        |
              +--------------------------------------+
              | 1      bottom     bottom left front  |
              | 2       left       bottom left back  |
              | 4        top      bottom right front |
              | 8       right     bottom right back  |
              | 16    no effect     left vertical    |
              | 32    no effect     back vertical    |
              | 64    no effect     right vertical   |
              |128    no effect     front vertical   |
              |256    no effect     top left back    |
              |512    no effect     top right back   |
              |1024   no effect     top left front   |
              |2048   no effect    top right front   |
              +--------------------------------------+











GNUPLOT 4.1                                                      102


Various bits or combinations of bits may be added together in the
command.

The default is 31, which is all four sides for [1mplot[22m, and base and z
axis for [1msplot[22m.

In 2D plots the border is normally drawn on top of all plots ele-
ments ([1mfront[22m). If you want the border to be drawn behind the plot
elements, use [1mset border back[22m.

Using the optional <line_style>, <line_type> and <line_width> speci-
fiers, the way the border lines are drawn can be influenced (limited
by what the current terminal driver supports).

For [1mplot[22m, tics may be drawn on edges other than bottom and left by
enabling the second axes -- see [1mset xtics [22mfor details.

If a [1msplot [22mdraws only on the base, as is the case with "[1munset sur-[0m
[1mface; set contour base[22m", then the verticals and the top are not
drawn even if they are specified.

The [1mset grid [22moptions 'back', 'front' and 'layerdefault' also control
the order in which the border lines are drawn with respect to the
output of the plotted data.

Examples:

Draw default borders:
      set border

Draw only the left and bottom ([1mplot[22m) or both front and back bottom
left ([1msplot[22m) borders:
      set border 3

Draw a complete box around a [1msplot[22m:
      set border 4095

Draw a topless box around a [1msplot[22m, omitting the front vertical:
      set border 127+256+512 # or set border 1023-128

Draw only the top and right borders for a [1mplot [22mand label them as
axes:
      unset xtics; unset ytics; set x2tics; set y2tics; set border
12




     [1m45.7.  Boxwidth[0m


     The [1mset boxwidth [22mcommand is used to set the default width of
     boxes in the [1mboxes[22m, [1mboxerrorbars[22m, [1mcandlesticks [22mand [1mhistograms[0m










GNUPLOT 4.1                                                      103


     styles.

     Syntax:
           set boxwidth {<width>} {absolute|relative}
           show boxwidth

     By default, adjacent boxes are extended in width until they
     touch each other.  A different default width may be specified
     using the [1mset boxwidth [22mcommand.  [1mRelative [22mwidths are inter-
     preted as being a fraction of this default width.

     An explicit value for the boxwidth is interpreted as being a
     number of units along the current x axis ([1mabsolute[22m) unless the
     modifier [1mrelative [22mis given.  If the x axis is a log-scale (see
     [1mset log[22m) then the value of boxwidth is truly "absolute" only at
     x=1; this physical width is maintained everywhere along the
     axis (i.e. the boxes do not become narrower the value of x
     increases). If the range spanned by a log scale x axis is far
     from x=1, some experimentation may be required to find a useful
     value of boxwidth.

     The default is superseded by explicit width information taken
     from an extra data column in styles [1mboxes [22mor [1mboxerrorbars[22m.  In
     a four-column data set, the fourth column will be interpreted
     as the box width unless the width is set to -2.0, in which case
     the width will be calculated automatically.  See [1mstyle boxes[0m
     and [1mstyle boxerrorbars [22mfor more details.

     To set the box width to automatic use the command
           set boxwidth

     or, for four-column data,
           set boxwidth -2

     The same effect can be achieved with the [1musing [22mkeyword in [1mplot[22m:
           plot 'file' using 1:2:3:4:(-2)

     To set the box width to half of the automatic size use
           set boxwidth 0.5 relative

     To set the box width to an absolute value of 2 use
           set boxwidth 2 absolute



     [1m45.8.  Clabel[0m


     [1mgnuplot [22mwill vary the linetype used for each contour level when
     clabel is set.  When this option on (the default), a legend
     labels each linestyle with the z level it represents.  It is
     not possible at present to separate the contour labels from the
     surface key.










GNUPLOT 4.1                                                      104


     Syntax:
           set clabel {'<format>'}
           unset clabel
           show clabel

     The default for the format string is %8.3g, which gives three
     decimal places.  This may produce poor label alignment if the
     key is altered from its default configuration.

     The first contour linetype, or only contour linetype when cla-
     bel is off, is the surface linetype +1; contour points are the
     same style as surface points.

     See also [1mset contour[22m.



     [1m45.9.  Clip[0m


     [1mgnuplot [22mcan clip data points and lines that are near the bound-
     aries of a graph.

     Syntax:
           set clip <clip-type>
           unset clip <clip-type>
           show clip

     Three clip types for points and lines are supported by [1mgnuplot[22m:
     [1mpoints[22m, [1mone[22m, and [1mtwo[22m. One, two, or all three clip types may be
     active for a single graph.  Note that clipping of color filled
     quadrangles drawn by [1mpm3d [22mmaps and surfaces is not controlled
     by this command, but by [1mset pm3d clip1in [22mand [1mset pm3d clip4in[22m.

     The [1mpoints [22mclip type forces [1mgnuplot [22mto clip (actually, not plot
     at all) data points that fall within but too close to the
     boundaries.  This is done so that large symbols used for points
     will not extend outside the boundary lines.  Without clipping
     points near the boundaries, the plot may look bad.  Adjusting
     the x and y ranges may give similar results.

     Setting the [1mone [22mclip type causes [1mgnuplot [22mto draw a line segment
     which has only one of its two endpoints within the graph.  Only
     the in-range portion of the line is drawn.  The alternative is
     to not draw any portion of the line segment.

     Some lines may have both endpoints out of range, but pass
     through the graph.  Setting the [1mtwo [22mclip-type allows the visi-
     ble portion of these lines to be drawn.

     In no case is a line drawn outside the graph.

     The defaults are [1mnoclip points[22m, [1mclip one[22m, and [1mnoclip two[22m.










GNUPLOT 4.1                                                      105


     To check the state of all forms of clipping, use
           show clip

     For backward compatibility with older versions, the following
     forms are also permitted:
           set clip
           unset clip

     [1mset clip [22mis synonymous with [1mset clip points[22m; [1munset clip [22mturns
     off all three types of clipping.



     [1m45.10.  Cntrparam[0m


     [1mset cntrparam [22mcontrols the generation of contours and their
     smoothness for a contour plot. [1mshow contour [22mdisplays current
     settings of [1mcntrparam [22mas well as [1mcontour[22m.

     Syntax:
           set cntrparam { { linear
                           | cubicspline
                           | bspline
                           | points <n>
                           | order <n>
                           | levels { auto {<n>} | <n>
                                      | discrete <z1>
     {,<z2>{,<z3>...}}
                                      | incremental <start>, <incr>
     {,<end>}
                                    }
                           }
                         }
           show contour

     This command has two functions.  First, it sets the values of z
     for which contour points are to be determined (by linear inter-
     polation between data points or function isosamples.)  Second,
     it controls the way contours are drawn between the points
     determined to be of equal z.  <n> should be an integral con-
     stant expression and <z1>, <z2> ... any constant expressions.
     The parameters are:

     [1mlinear[22m, [1mcubicspline[22m, [1mbspline[22m---Controls type of approximation
     or interpolation.  If [1mlinear[22m, then straight line segments con-
     nect points of equal z magnitude.  If [1mcubicspline[22m, then piece-
     wise-linear contours are interpolated between the same equal z
     points to form somewhat smoother contours, but which may undu-
     late.  If [1mbspline[22m, a guaranteed-smoother curve is drawn, which
     only approximates the position of the points of equal-z.

     [1mpoints[22m---Eventually all drawings are done with piecewise-linear










GNUPLOT 4.1                                                      106


     strokes.  This number controls the number of line segments used
     to approximate the [1mbspline [22mor [1mcubicspline [22mcurve.  Number of
     cubicspline or bspline segments (strokes) = [1mpoints [22m* number of
     linear segments.

     [1morder[22m---Order of the bspline approximation to be used.  The
     bigger this order is, the smoother the resulting contour.  (Of
     course, higher order bspline curves will move further away from
     the original piecewise linear data.)  This option is relevant
     for [1mbspline [22mmode only.  Allowed values are integers in the
     range from 2 (linear) to 10.

     [1mlevels[22m--- Selection of contour levels,  controlled by [1mauto[0m
     (default), [1mdiscrete[22m, [1mincremental[22m, and <n>, number of contour
     levels.

     For [1mauto[22m, <n> specifies a nominal number of levels; the actual
     number will be adjusted to give simple labels. If the surface
     is bounded by zmin and zmax, contours will be generated at
     integer multiples of dz between zmin and zmax, where dz is 1,
     2, or 5 times some power of ten (like the step between two tic
     marks).

     For [1mlevels discrete[22m, contours will be generated at z = <z1>,
     <z2> ... as specified; the number of discrete levels sets the
     number of contour levels.  In [1mdiscrete [22mmode, any [1mset cntrparam[0m
     [1mlevels <n> [22mare ignored.

     For [1mincremental[22m, contours are generated at values of z begin-
     ning at <start> and increasing by <increment>, until the number
     of contours is reached. <end> is used to determine the number
     of contour levels, which will be changed by any subsequent [1mset[0m
     [1mcntrparam levels <n>[22m.  If the z axis is logarithmic, <incre-
     ment> will be interpreted as a factor, just like in [1mset ztics[22m.

     If the command [1mset cntrparam [22mis given without any arguments
     specified,  the defaults are used: linear, 5 points, order 4, 5
     auto levels.

     Examples:
           set cntrparam bspline
           set cntrparam points 7
           set cntrparam order 10

     To select levels automatically, 5 if the level increment crite-
     ria are met:
           set cntrparam levels auto 5

     To specify discrete levels at .1, .37, and .9:
           set cntrparam levels discrete .1,1/exp(1),.9

     To specify levels from 0 to 4 with increment 1:
           set cntrparam levels incremental  0,1,4










GNUPLOT 4.1                                                      107


     To set the number of levels to 10 (changing an incremental end
     or possibly the number of auto levels):
           set cntrparam levels 10

     To set the start and increment while retaining the number of
     levels:
           set cntrparam levels incremental 100,50

     See also [1mset contour [22mfor control of where the contours are
     drawn, and [1mset clabel [22mfor control of the format of the contour
     labels and linetypes.

     See also contours demo (contours.dem) and contours with user
     defined levels demo (discrete.dem).



     [1m45.11.  Color box[0m



     The color scheme, i.e. the gradient of the smooth color with
     min_z and max_z values of [1mpm3d[22m's [1mpalette[22m, is drawn in a color
     box unless [1munset colorbox[22m.

           set colorbox
           set colorbox {
                      { vertical | horizontal }
                      { default | user }
                      { origin x, y }
                      { size x, y }
                      { noborder | bdefault | border [line style] }
                    }
           show colorbox
           unset colorbox

     Colorbox position can be [1mdefault [22mor [1muser[22m.  If the latter is
     specified the values as given with the [1morigin [22mand [1msize [22msubcom-
     mands are used.

     [1mvertical [22mand [1mhorizontal [22mswitches the orientation of the color
     gradient.

     [1morigin x, y [22mand [1msize x, y [22mare used only in combination with the
     [1muser [22moption. The x and y values are interpreted as screen coor-
     dinates by default, and this is the only legal option for 3D
     plots. 2D plots, including splot with [1mset view map[22m, allow any
     coordinate system to be specified.  Try for example:
         set colorbox horiz user origin .1,.02 size .8,.04
     which will draw a horizontal gradient somewhere at the bottom
     of the graph.

     [1mborder [22mturns the border on (this is the default). [1mnoborder[0m










GNUPLOT 4.1                                                      108


     turns the border off. If an positive integer argument is given
     after [1mborder[22m, it is used as a line style tag which is used for
     drawing the border, e.g.:
         set style line 2604 linetype -1 linewidth .4
         set colorbox border 2604
     will use line style [1m2604[22m, a thin line with the default border
     color (-1) for drawing the border. [1mbdefault [22m(which is the
     default) will use the default border line style for drawing the
     border of the color box.

     The axis of the color box is called [1mcb [22mand it is controlled by
     means of the usual axes commands, i.e. [1mset/unset/show [22mwith
     [1mcbrange[22m, [1m[m]cbtics[22m, [1mformat cb[22m, [1mgrid [m]cb[22m, [1mcblabel[22m, and perhaps
     even [1mcbdata[22m, [1m[no]cbdtics[22m, [1m[no]cbmtics[22m.

     [1mset colorbox [22mwithout any parameter switches the position to
     default.  [1munset colorbox [22mresets the default parameters for the
     colorbox and switches the colorbox off.

     See also help for [1mset pm3d[22m, [1mset palette[22m, [1mx11 pm3d[22m, and [1mset[0m
     [1mstyle line[22m.




     [1m45.12.  Contour[0m


     [1mset contour [22menables contour drawing for surfaces.  This option
     is available for [1msplot [22monly.  It requires grid data, see
     [1mgrid_data [22mfor more details.  If contours are desired from non-
     grid data, [1mset dgrid3d [22mcan be used to create an appropriate
     grid.

     Syntax:
           set contour {base | surface | both}
           unset contour
           show contour

     The three options specify where to draw the contours: [1mbase[0m
     draws the contours on the grid base where the x/ytics are
     placed, [1msurface [22mdraws the contours on the surfaces themselves,
     and [1mboth [22mdraws the contours on both the base and the surface.
     If no option is provided, the default is [1mbase[22m.

     See also [1mset cntrparam [22mfor the parameters that affect the draw-
     ing of contours, and [1mset clabel [22mfor control of labelling of the
     contours.

     The surface can be switched off (see [1mset surface[22m), giving a
     contour-only graph.  Though it is possible to use [1mset size [22mto
     enlarge the plot to fill the screen, more control over the out-
     put format can be obtained by writing the contour information










GNUPLOT 4.1                                                      109


     to a file, and rereading it as a 2-d datafile plot:

           unset surface
           set contour
           set cntrparam ...
           set table 'filename'
           splot ...
           unset table
           # contour info now in filename
           set term <whatever>
           plot 'filename'

     In order to draw contours, the data should be organized as
     "grid data".  In such a file all the points for a single y-iso-
     line are listed, then all the points for the next y-isoline,
     and so on.  A single blank line (a line containing no charac-
     ters other than blank spaces and a carriage return and/or a
     line feed) separates one y-isoline from the next.  See also
     [1msplot datafile[22m.

     See also contours demo (contours.dem) and contours with user
     defined levels demo (discrete.dem).



     [1m45.13.  Data style[0m


     This form of the command is deprecated. Please see [1mset style[0m
     [1mdata[22m.



     [1m45.14.  Datafile[0m


     The [1mset datafile [22mcommand options control interpretation of
     fields read from input data files by the [1mplot[22m, [1msplot[22m, and [1mfit[0m
     commands.  Four such options are currently implemented.




          [1m45.14.1.  Set datafile fortran[0m


          The [1mset datafile fortran [22mcommand enables a special check
          for values in the input file expressed as Fortran D or Q
          constants. This extra check slows down the input process,
          and should only be selected if you do in fact have
          datafiles containing Fortran D or Q constants. The option
          can be disabled again using [1munset datafile fortran[22m.











GNUPLOT 4.1                                                      110


          [1m45.14.2.  Set datafile missing[0m


          The [1mset datafile missing [22mcommand allows you to tell [1mgnu-[0m
          [1mplot [22mwhat character string is used in a data file to
          denote missing data.  Exactly how this missing value will
          be treated depends on the [1musing [22mspecifier of the [1mplot [22mor
          [1msplot [22mcommand.

          Syntax:
                set datafile missing {"<string>"}
                show datafile missing
                unset datafile

          Example:
                # Ignore entries containing IEEE NaN ("Not a Num-
          ber") code
                set datafile missing "NaN"

          Example:
                set datafile missing "?"
                set style data lines
                plot '-'
                   1 10
                   2 20
                   3 ?
                   4 40
                   5 50
                   e
                plot '-' using 1:2
                   1 10
                   2 20
                   3 ?
                   4 40
                   5 50
                   e
                plot '-' using 1:($2)
                   1 10
                   2 20
                   3 ?
                   4 40
                   5 50
                   e

          The first [1mplot [22mwill recognize only the first datum in the
          "3 ?" line.  It will use the single-datum-on-a-line con-
          vention that the line number is "x" and the datum is "y",
          so the point will be plotted (in this case erroneously) at
          (2,3).

          The second [1mplot [22mwill correctly ignore the middle line.
          The plotted line will connect the points at (2,20) and
          (4,40).










GNUPLOT 4.1                                                      111


          The third [1mplot [22mwill also correctly ignore the middle line,
          but the plotted line will not connect the points at (2,20)
          and (4,40).

          There is no default character for [1mmissing[22m, but in many
          cases any non-parsible string of characters found where a
          numerical value is expected will be treated as missing
          data.




          [1m45.14.3.  Set datafile separator[0m


          The command [1mset datafile separator "<char>" [22mtells [1mgnuplot[0m
          that data fields in subsequent input files are separated
          by <char> rather than by whitespace.  The most common use
          is to read in csv (comma-separated value) files written by
          spreadsheet or database programs. By default data fields
          are separated by whitespace.

          Syntax:
                set datafile separator {"<char>" | whitespace}

          Examples:
                # Input file contains tab-separated fields
                set datafile separator "\t"

                # Input file contains comma-separated values fields
                set datafile separator ","



          [1m45.14.4.  Set datafile commentschars[0m


          The [1mset datafile commentschars [22mcommand allows you to tell
          [1mgnuplot [22mwhat characters are used in a data file to denote
          comments.  Gnuplot will ignore rest of the line behind the
          specified characters if either of them is the first non-
          blank character on the line.

          Syntax:
                set datafile commentschars {"<string>"}
                show datafile commentschars
                unset commentschars

          Default value of the string is "#!" on VMS and "#" other-
          wise.

          Then, the following line in a data file is completely
          ignored










GNUPLOT 4.1                                                      112


              # 1 2 3 4
          but the following
              1 # 3 4
          produces rather unexpected plot unless
              set datafile missing '#'
          is specified as well.

          Example:
                set datafile commentschars "#!%"



          [1m45.14.5.  Set datafile binary[0m


          The [1mset datafile binary [22mcommand is used to set the
          defaults when reading binary data files.  The syntax
          matches precisely that used for commands [1mplot [22mand [1msplot[22m.
          See [1mbinary [22mfor details about <binary list>.

          Syntax:
                set datafile binary <binary list>
                show datafile binary
                show datafile
                unset datafile

          Examples:
                set datafile binary filetype=auto
                set datafile binary array=512x512 format="%uchar"



     [1m45.15.  Decimalsign[0m


     The [1mset decimalsign [22mcommand selects a decimal sign for numbers
     printed into tic labels or [1mset label [22mstrings.

     Syntax:
           set decimalsign {<value> | locale {"<locale>"}}
           unset decimalsign
           show decimalsign

     The argument <value> is a string to be used in place of the
     usual decimal point. Typical choices include the period, '.',
     and the comma, ',', but others may be useful, too.  If you omit
     the <value> argument, the decimal separator is not modified
     from the usual default, which is a period.  Unsetting decimal-
     sign has the same effect as omitting <value>.

     Example:

     Correct typesetting in most European countries requires:










GNUPLOT 4.1                                                      113


           set decimalsign ','

     Please note: If you set an explicit string, this affects only
     numbers that are printed using gnuplot's gprintf() formatting
     routine, include axis tics.  It does not affect the format
     expected for input data, and it does not affect numbers printed
     with the sprintf() formatting routine. To change the behavior
     of both input and output formatting, instead use the form

           set decimalsign locale

     This instructs the program to use both input and output formats
     in accordance with the current setting of the LC_ALL,
     LC_NUMERIC, or LANG environmental variables.

           set decimalsign locale "foo"

     This instructs the program to format all input and output in
     accordance with locale "foo", which must be installed.  If
     locale "foo" is not found then an error message is printed and
     the decimal sign setting is unchanged.  On linux systems you
     can get a list of the locales installed on your machine by typ-
     ing "locale -a". A typical linux locale string is of the form
     "sl_SI.UTF-8".  A typical Windows locale string is of the form
     "Slovenian_Slovenia.1250" or "slovenian". Please note that
     interpretation of the locale settings is done by the C library
     at runtime. Older C libraries may offer only partial support
     for locale settings such as the thousands grouping separator
     character.

           set decimalsign locale; set decimalsign "."

     This sets all input and output to use whatever decimal sign is
     correct for the current locale, but over-rides this with an
     explicit '.' in numbers formatted using gnuplot's internal
     gprintf() function.



     [1m45.16.  Dgrid3d[0m


     The [1mset dgrid3d [22mcommand enables, and can set parameters for,
     non-grid to grid data mapping.  See [1msplot grid_data [22mfor more
     details about the grid data structure.

     Syntax:
           set dgrid3d {<row_size>} {,{<col_size>} {,<norm>}}
           unset dgrid3d
           show dgrid3d

     By default [1mdgrid3d [22mis disabled.  When enabled, 3-d data read
     from a file are always treated as a scattered data set.  A grid










GNUPLOT 4.1                                                      114


     with dimensions derived from a bounding box of the scattered
     data and size as specified by the row/col_size parameters is
     created for plotting and contouring.  The grid is equally
     spaced in x (rows) and in y (columns); the z values are com-
     puted as weighted averages of the scattered points' z values.

     The third parameter, norm, controls the weighting:  Each data
     point is weighted inversely by its distance from the grid point
     raised to the norm power.  (Actually, the weights are given by
     the inverse of dx^norm + dy^norm, where dx and dy are the com-
     ponents of the separation of the grid point from each data
     point.  For some norms that are powers of two, specifically 4,
     8, and 16, the computation is optimized by using the Euclidean
     distance in the weight calculation, (dx^2+dy^2)^norm/2.  How-
     ever, any non-negative integer can be used.)

     The closer the data point is to a grid point, the more effect
     it has on that grid point and the larger the value of norm the
     less effect more distant data points have on that grid point.

     The [1mdgrid3d [22moption is a simple low pass filter that converts
     scattered data to a grid data set.  More sophisticated
     approaches to this problem exist and should be used to prepro-
     cess the data outside [1mgnuplot [22mif this simple solution is found
     inadequate.

     (The z values are found by weighting all data points, not by
     interpolating between nearby data points;  also edge effects
     may produce unexpected and/or undesired results.  In some
     cases, small norm values produce a grid point reflecting the
     average of distant data points rather than a local average,
     while large values of norm may produce "steps" with several
     grid points having the same value as the closest data point,
     rather than making a smooth transition between adjacent data
     points.  Some areas of a grid may be filled by extrapolation,
     to an arbitrary boundary condition.  The variables are not nor-
     malized; consequently the units used for x and y will affect
     the relative weights of points in the x and y directions.)

     Examples:
           set dgrid3d 10,10,1     # defaults
           set dgrid3d ,,4

     The first specifies that a grid of size 10 by 10 is to be con-
     structed using a norm value of 1 in the weight computation.
     The second only modifies the norm, changing it to 4.  See also
     scatter.dem: dgrid3d demo.
















GNUPLOT 4.1                                                      115


     [1m45.17.  Dummy[0m


     The [1mset dummy [22mcommand changes the default dummy variable names.

     Syntax:
           set dummy {<dummy-var>} {,<dummy-var>}
           show dummy

     By default, [1mgnuplot [22massumes that the independent, or "dummy",
     variable for the [1mplot [22mcommand is "t" if in parametric or polar
     mode, or "x" otherwise.  Similarly the independent variables
     for the [1msplot [22mcommand are "u" and "v" in parametric mode ([1msplot[0m
     cannot be used in polar mode), or "x" and "y" otherwise.

     It may be more convenient to call a dummy variable by a more
     physically meaningful or conventional name.  For example, when
     plotting time functions:

           set dummy t
           plot sin(t), cos(t)

     At least one dummy variable must be set on the command; [1mset[0m
     [1mdummy [22mby itself will generate an error message.

     Examples:
           set dummy u,v
           set dummy ,s

     The second example sets the second variable to s.



     [1m45.18.  Encoding[0m


     The [1mset encoding [22mcommand selects a character encoding.  Syntax:
           set encoding {<value>}
           show encoding

     Valid values are
        default     - tells a terminal to use its default encoding
        iso_8859_1  - the most common Western European font used by
     many
                      Unix workstations and by MS-Windows. This
     encoding is
                      known in the PostScript world as 'ISO-Latin1'.
        iso_8859_2  - used in Central and Eastern Europe
        iso_8859_15 - a variant of iso_8859_1 that includes the Euro
     symbol
        koi8r       - popular Unix cyrillic encoding
        koi8u       - ukrainian Unix cyrillic encoding
        cp437       - codepage for MS-DOS










GNUPLOT 4.1                                                      116


        cp850       - codepage for OS/2, Western Europe
        cp852       - codepage for OS/2, Central and Eastern Europe
        cp1250      - codepage for MS Windows, Central and Eastern
     Europe

     Generally you must set the encoding before setting the terminal
     type.  Note that encoding is not supported by all terminal
     drivers and that the device must be able to produce the desired
     non-standard characters.  The PostScript, X11 and wxt terminals
     support all encodings. OS/2 Presentation Manager switches auto-
     matically to codepage 912 for [1miso_8859_2[22m.



     [1m45.19.  Fit[0m


     The [1mfit [22msetting defines where the [1mfit [22mcommand writes its out-
     put.  If this option was built into your version of gnuplot, it
     also controls whether parameter errors from the fit will be
     written into variables.

     Syntax:
           set fit {logfile {"<filename>"}} {{no}errorvariables}
           unset fit
           show fit

     The <filename> argument must be enclosed in single or double
     quotes.

     If no filename is given or [1munset fit [22mis used the log file is
     reset to its default value "fit.log" or the value of the envi-
     ronmental variable [1mFIT_LOG[22m.

     Users of DOS-like platforms should note that the \ character
     has special significance in double-quoted strings, so single-
     quotes should be used for filenames in different directories,
     or you have to write \\ for each \.  Or you can just use for-
     ward slashes, even though this is DOS.

     If the given logfile name ends with a / or \, it is interpreted
     to be a directory name, and the actual filename will be
     "fit.log" in that directory.

     If the [1merrorvariables [22moption is turned on, the error of each
     fitted parameter computed by [1mfit [22mwill be copied to a user-
     defined variable whose name is formed by appending "_err" to
     the name of the parameter itself.  This is useful mainly to put
     the parameter and its error onto a plot of the data and the
     fitted function, for reference, as in:

            set fit errorvariables
            fit f(x) 'datafile' using 1:2 via a, b










GNUPLOT 4.1                                                      117


            print "error of a is:", a_err
            set label 'a=%6.2f', a, '+/- %6.2f', a_err
            plot 'datafile' using 1:2, f(x)



     [1m45.20.  Fontpath[0m


     The [1mfontpath [22msetting defines additional locations for font
     files searched when including font files. Currently only the
     postscript terminal supports [1mfontpath[22m. If a file cannot be
     found in the current directory, the directories in [1mfontpath [22mare
     tried. Further documentation concerning the supported file for-
     mats is included in the [1mterminal postscript [22msection of the doc-
     umentation.

     Syntax:
           set fontpath {"pathlist1" {"pathlist2"...}}
           show fontpath

     Path names may be entered as single directory names, or as a
     list of path names separated by a platform-specific path sepa-
     rator, eg. colon (':') on Unix, semicolon (';') on DOS/Win-
     dows/OS/2/Amiga platforms.  The [1mshow fontpath[22m, [1msave [22mand [1msave[0m
     [1mset [22mcommands replace the platform-specific separator with a
     space character (' ') for maximum portability. If a directory
     name ends with an exclamation mark ('!') also the subdirecto-
     ries of this directory are searched for font files.

     If the environmental variable GNUPLOT_FONTPATH is set, its con-
     tents are appended to [1mfontpath[22m.  If it is not set, a system
     dependent default value is used. It is set by testing several
     directories for existence when using the fontpath the first
     time. Thus, the first call of [1mset fontpath[22m, [1mshow fontpath[22m, [1msave[0m
     [1mfontpath[22m, [1mplot[22m, or [1msplot [22mwith embedded font files takes a lit-
     tle more time. If you want to save this time you may set the
     environmental variable GNUPLOT_FONTPATH since probing is
     switched off, then. You can find out which is the default font-
     path by using [1mshow fontpath[22m.

     However, [1mshow fontpath [22mprints the contents of user defined
     fontpath and system fontpath separately.  Also, the [1msave [22mand
     [1msave set [22mcommands save only the user specified parts of [1mfont-[0m
     [1mpath[22m, for portability reasons.

     Many other terminal drivers access TrueType fonts via the gd
     library.  For these drivers the font search path is controlled
     by the environmental variable GDFONTPATH.














GNUPLOT 4.1                                                      118


     [1m45.21.  Format[0m


     The format of the tic-mark labels can be set with the [1mset for-[0m
     [1mmat [22mcommand.

     Syntax:
           set format {<axes>} {"<format-string>"}
           set format {<axes>} {'<format-string>'}
           show format

     where <axes> is either [1mx[22m, [1my[22m, [1mxy[22m, [1mx2[22m, [1my2[22m, [1mz[22m, [1mcb [22mor nothing
     (which refers to all axes at once).  The length of the string
     representing a tic mark (after formatting with 'printf') is
     restricted to 100 characters.  If the format string is omitted,
     the format will be returned to the default "% g".  For LaTeX
     users, the format "$%g$" is often desirable.  If the empty
     string "" is used, no label will be plotted with each tic,
     though the tic mark will still be plotted.  To eliminate all
     tic marks, use [1munset xtics [22mor [1munset ytics[22m.

     Newline (\n) is accepted in the format string.  Use double-
     quotes rather than single-quotes to enable such interpretation.
     See also [1msyntax[22m.

     The default format for both axes is "% g", but other formats
     such as "%.2f" or "%3.0em" are often desirable.  Anything
     accepted by 'printf' when given a double precision number, and
     accepted by the terminal, will work.  Some other options have
     been added.  If the format string looks like a floating point
     format, then [1mgnuplot [22mtries to construct a reasonable format.

     Characters not preceded by "%" are printed verbatim.  Thus you
     can include spaces and labels in your format string, such as
     "%g m", which will put " m" after each number.  If you want "%"
     itself, double it: "%g %%".

     See also [1mset xtics [22mfor more information about tic labels, and
     [1mset decimalsign [22mfor how to use non-default decimal separators
     in numbers printed this way.  See also electron demo (elec-
     tron.dem).




          [1m45.21.1.  Gprintf[0m


          The string function gprintf("format",x) uses gnuplot's own
          format specifiers, as do the gnuplot commands [1mset format[22m,
          [1mset timestamp[22m, and others. These format specifiers are not
          the same as those used by the standard C-language routine
          sprintf(). Gnuplot also provides an










GNUPLOT 4.1                                                      119


          sprintf("format",x,...) routine if you prefer. For a list
          of gnuplot's format options, see [1mformat specifiers[22m.



          [1m45.21.2.  Format specifiers[0m


          The acceptable formats (if not in time/date mode) are:




+------------------------------------------------------------------+
| Format    Explanation                                            |
+------------------------------------------------------------------+
|   %f      floating point notation                                |
|%e or %E   exponential notation; an "e" or "E" before the power   |
|%g or %G   the shorter of %e (or %E) and %f                       |
|%x or %X   hex                                                    |
|%o or %O   octal                                                  |
|   %t      mantissa to base 10                                    |
|   %l      mantissa to base of current logscale                   |
|   %s      mantissa to base of current logscale; scientific power |
|   %T      power to base 10                                       |
|   %L      power to base of current logscale                      |
|   %S      scientific power                                       |
|   %c      character replacement for scientific power             |
|   %P      multiple of pi                                         |
+------------------------------------------------------------------+
+------------------------------------------------------------------+



A 'scientific' power is one such that the exponent is a multiple of
three.  Character replacement of scientific powers ([1m"%c"[22m) has been
implemented for powers in the range -18 to +18.  For numbers outside
of this range the format reverts to exponential.

Other acceptable modifiers (which come after the "%" but before the
format specifier) are "-", which left-justifies the number; "+",
which forces all numbers to be explicitly signed; " " (a space),
which makes positive numbers have a space in front of them where
negative numbers have "-"; "#", which places a decimal point after
floats that have only zeroes following the decimal point; a positive
integer, which defines the field width; "0" (the digit, not the let-
ter) immediately preceding the field width, which indicates that
leading zeroes are to be used instead of leading blanks; and a deci-
mal point followed by a non-negative integer, which defines the pre-
cision (the minimum number of digits of an integer, or the number of
digits following the decimal point of a float).

Some systems may not support all of these modifiers but may also










GNUPLOT 4.1                                                      120


support others; in case of doubt, check the appropriate documenta-
tion and then experiment.

Examples:
      set format y "%t"; set ytics (5,10)          # "5.0" and "1.0"
      set format y "%s"; set ytics (500,1000)      # "500" and "1.0"
      set format y "%+-12.3f"; set ytics(12345)    # "+12345.000  "
      set format y "%.2t*10^%+03T"; set ytic(12345)# "1.23*10^+04"
      set format y "%s*10^{%S}"; set ytic(12345)   # "12.345*10^{3}"
      set format y "%s %cg"; set ytic(12345)       # "12.345 kg"
      set format y "%.0P pi"; set ytic(6.283185)   # "2 pi"
      set format y "%.0f%%"; set ytic(50)          # "50%"

      set log y 2; set format y '%l'; set ytics (1,2,3)
      #displays "1.0", "1.0" and "1.5" (since 3 is 1.5 * 2^1)

There are some problem cases that arise when numbers like 9.999 are
printed with a format that requires both rounding and a power.

If the data type for the axis is time/date, the format string must
contain valid codes for the 'strftime' function (outside of [1mgnuplot[22m,
type "man strftime").  See [1mset timefmt [22mfor a list of the allowed
input format codes.



          [1m45.21.3.  Time/date specifiers[0m


          In time/date mode, the acceptable formats are:

































GNUPLOT 4.1                                                      121


       +----------------------------------------------------+
       | Format    Explanation                              |
       +----------------------------------------------------+
       |   %a      abbreviated name of day of the week      |
       |   %A      full name of day of the week             |
       |%b or %h   abbreviated name of the month            |
       |   %B      full name of the month                   |
       |   %d      day of the month, 1--31                  |
       |   %D      shorthand for "%m/%d/%y"                 |
       |   %k      hour, 0--23 (one or two digits)          |
       |   %H      hour, 00--23 (always two digits)         |
       |   %l      hour, 1--12 (one or two digits)          |
       |   %I      hour, 01--12 (always two digits)         |
       |   %j      day of the year, 1--366                  |
       |   %m      month, 1--12                             |
       |   %M      minute, 0--60                            |
       |   %p      "am" or "pm"                             |
       |   %r      shorthand for "%I:%M:%S %p"              |
       |   %R      shorthand for %H:%M"                     |
       |   %S      second, 0--60                            |
       |   %T      shorthand for "%H:%M:%S"                 |
       |   %U      week of the year (week starts on Sunday) |
       |   %w      day of the week, 0--6 (Sunday = 0)       |
       |   %W      week of the year (week starts on Monday) |
       |   %y      year, 0-99                               |
       |   %Y      year, 4-digit                            |
       +----------------------------------------------------+
       +----------------------------------------------------+



Except for the non-numerical formats, these may be preceded by a "0"
("zero", not "oh") to pad the field length with leading zeroes, and
a positive digit, to define the minimum field width (which will be
overridden if the specified width is not large enough to contain the
number).  There is a 24-character limit to the length of the printed
text; longer strings will be truncated.

Examples:

Suppose the text is "76/12/25 23:11:11".  Then
      set format x                 # defaults to "12/25/76" \n
"23:11"
      set format x "%A, %d %b %Y"  # "Saturday, 25 Dec 1976"
      set format x "%r %D"         # "11:11:11 pm 12/25/76"

Suppose the text is "98/07/06 05:04:03".  Then
      set format x "%1y/%2m/%3d %01H:%02M:%03S"  # "98/ 7/  6
5:04:003"














GNUPLOT 4.1                                                      122


     [1m45.22.  Function style[0m


     This form of the command is deprecated. Please see [1mset style[0m
     [1mfunction[22m.



     [1m45.23.  Functions[0m


     The [1mshow functions [22mcommand lists all user-defined functions and
     their definitions.

     Syntax:
           show functions

     For information about the definition and usage of functions in
     [1mgnuplot[22m, please see [1mexpressions[22m.  See also splines as user
     defined functions (spline.dem) and use of functions and complex
     variables for airfoils (airfoil.dem).



     [1m45.24.  Grid[0m


     The [1mset grid [22mcommand allows grid lines to be drawn on the plot.

     Syntax:
           set grid {{no}{m}xtics} {{no}{m}ytics} {{no}{m}ztics}
                    {{no}{m}x2tics} {{no}{m}y2tics}
                    {{no}{m}cbtics}
                    {polar {<angle>}}
                    {layerdefault | front | back}
                    { {linestyle <major_linestyle>}
                      | {linetype | lt <major_linetype>}
                        {linewidth | lw <major_linewidth>}
                      { , {linestyle | ls <minor_linestyle>}
                          | {linetype | lt <minor_linetype>}
                            {linewidth | lw <minor_linewidth>} } }
           unset grid
           show grid

     The grid can be enabled and disabled for the major and/or minor
     tic marks on any axis, and the linetype and linewidth can be
     specified for major and minor grid lines, also via a predefined
     linestyle, as far as the active terminal driver supports this.

     Additionally, a polar grid can be selected for 2-d plots---cir-
     cles are drawn to intersect the selected tics, and radial lines
     are drawn at definable intervals.  (The interval is given in
     degrees or radians, depending on the [1mset angles [22msetting.)  Note










GNUPLOT 4.1                                                      123


     that a polar grid is no longer automatically generated in polar
     mode.

     The pertinent tics must be enabled before [1mset grid [22mcan draw
     them; [1mgnuplot [22mwill quietly ignore instructions to draw grid
     lines at non-existent tics, but they will appear if the tics
     are subsequently enabled.

     If no linetype is specified for the minor gridlines, the same
     linetype as the major gridlines is used.  The default polar
     angle is 30 degrees.

     If [1mfront [22mis given, the grid is drawn on top of the graphed
     data. If [1mback [22mis given, the grid is drawn underneath the
     graphed data. Using [1mfront [22mwill prevent the grid from being
     obscured by dense data. The default setup, [1mlayerdefault[22m, is
     equivalent to [1mback [22mfor 2d plots.  In 3D plots the default is to
     split up the grid and the graph box into two layers: one
     behind, the other in front of the plotted data and functions.
     Since [1mhidden3d [22mmode does its own sorting, it ignores all grid
     drawing order options and passes the grid lines through the
     hidden line removal machinery instead. These options actually
     affect not only the grid, but also the lines output by [1mset bor-[0m
     [1mder [22mand the various ticmarks (see [1mset xtics[22m).

     Z grid lines are drawn on the bottom of the plot.  This looks
     better if a partial box is drawn around the plot---see [1mset bor-[0m
     [1mder[22m.



     [1m45.25.  Hidden3d[0m


     The [1mset hidden3d [22mcommand enables hidden line removal for sur-
     face plotting (see [1msplot[22m).  Some optional features of the
     underlying algorithm can also be controlled using this command.

     Syntax:
           set hidden3d {defaults} |
                        { {{offset <offset>} | {nooffset}}
                          {trianglepattern <bitpattern>}
                          {{undefined <level>} | {noundefined}}
                          {{no}altdiagonal}
                          {{no}bentover} }
           unset hidden3d
           show hidden3d

     In contrast to the usual display in gnuplot, hidden line
     removal actually treats the given function or data grids as
     real surfaces that can't be seen through, so parts behind the
     surface will be hidden by it.  For this to be possible, the
     surface needs to have 'grid structure' (see [1msplot datafile[0m










GNUPLOT 4.1                                                      124


     about this), and it has to be drawn [1mwith lines [22mor [1mwith lines-[0m
     [1mpoints[22m.

     When [1mhidden3d [22mis set, both the hidden portion of the surface
     and possibly its contours drawn on the base (see [1mset contour[22m)
     as well as the grid will be hidden.  Each surface has its hid-
     den parts removed with respect to itself and to other surfaces,
     if more than one surface is plotted.  Contours drawn on the
     surface ([1mset contour surface[22m) don't work.

     Labels and arrows are always visible and are unaffected.  The
     key box is never hidden by the surface. As of gnuplot version
     4.2, [1mset hidden3d [22malso affects 3D plotting styles [1mwith points[22m,
     [1mwith labels[22m, and [1mwith vectors[22m, even if no surface is present in
     the graph.  Individual plots within the graph may be explicitly
     excluded from this processing by appending the extra option
     [1mnohidden3d [22mto the [1mwith [22mspecifier.

     Hidden3d does not affect solid surfaces drawn using the pm3d
     mode. To achieve a similar effect for pm3d surfaces, use
     instead set [1mpm3d depthorder[22m.

     Functions are evaluated at isoline intersections.  The algo-
     rithm interpolates linearly between function points or data
     points when determining the visible line segments.  This means
     that the appearance of a function may be different when plotted
     with [1mhidden3d [22mthan when plotted with [1mnohidden3d [22mbecause in the
     latter case functions are evaluated at each sample.  Please see
     [1mset samples [22mand [1mset isosamples [22mfor discussion of the differ-
     ence.

     The algorithm used to remove the hidden parts of the surfaces
     has some additional features controllable by this command.
     Specifying [1mdefaults [22mwill set them all to their default set-
     tings, as detailed below.  If [1mdefaults [22mis not given, only
     explicitly specified options will be influenced: all others
     will keep their previous values, so you can turn on/off hidden
     line removal via [1mset {no}hidden3d[22m, without modifying the set of
     options you chose.

     The first option, [1moffset[22m, influences the linestyle used for
     lines on the 'back' side.  Normally, they are drawn in a
     linestyle one index number higher than the one used for the
     front, to make the two sides of the surface distinguishable.
     You can specify a different line style offset to add instead of
     the default 1, by [1moffset <offset>[22m.  Option [1mnooffset [22mstands for
     [1moffset 0[22m, making the two sides of the surface use the same
     linestyle.

     Next comes the option [1mtrianglepattern <bitpattern>[22m.  <bitpat-
     tern> must be a number between 0 and 7, interpreted as a bit
     pattern.  Each bit determines the visibility of one edge of the
     triangles each surface is split up into.  Bit 0 is for the










GNUPLOT 4.1                                                      125


     'horizontal' edges of the grid, Bit 1 for the 'vertical' ones,
     and Bit 2 for the diagonals that split each cell of the origi-
     nal grid into two triangles.  The default pattern is 3, making
     all horizontal and vertical lines visible, but not the diago-
     nals.  You may want to choose 7 to see those diagonals as well.

     The [1mundefined <level> [22moption lets you decide what the algorithm
     is to do with data points that are undefined (missing data, or
     undefined function values), or exceed the given x-, y- or z-
     ranges.  Such points can either be plotted nevertheless, or
     taken out of the input data set.  All surface elements touching
     a point that is taken out will be taken out as well, thus cre-
     ating a hole in the surface.  If <level> = 3, equivalent to
     option [1mnoundefined[22m, no points will be thrown away at all.  This
     may produce all kinds of problems elsewhere, so you should
     avoid this.  <level> = 2 will throw away undefined points, but
     keep the out-of-range ones.  <level> = 1, the default, will get
     rid of out-of-range points as well.

     By specifying [1mnoaltdiagonal[22m, you can override the default han-
     dling of a special case can occur if [1mundefined [22mis active (i.e.
     <level> is not 3).  Each cell of the grid-structured input sur-
     face will be divided in two triangles along one of its diago-
     nals.  Normally, all these diagonals have the same orientation
     relative to the grid.  If exactly one of the four cell corners
     is excluded by the [1mundefined [22mhandler, and this is on the usual
     diagonal, both triangles will be excluded.  However if the
     default setting of [1maltdiagonal [22mis active, the other diagonal
     will be chosen for this cell instead, minimizing the size of
     the hole in the surface.

     The [1mbentover [22moption controls what happens to another special
     case, this time in conjunction with the [1mtrianglepattern[22m.  For
     rather crumply surfaces, it can happen that the two triangles a
     surface cell is divided into are seen from opposite sides (i.e.
     the original quadrangle is 'bent over'), as illustrated in the
     following ASCII art:

                                                                   C----B
         original quadrangle:  A--B      displayed quadrangle:
     |\   |
           ("set view 0,0")    | /|    ("set view 75,75" perhaps)  |
     \  |
                               |/ |                                |
     \ |
                               C--D                                |
     \|
                                                                   A
     D

     If the diagonal edges of the surface cells aren't generally
     made visible by bit 2 of the <bitpattern> there, the edge CB
     above wouldn't be drawn at all, normally, making the resulting










GNUPLOT 4.1                                                      126


     display hard to understand.  Therefore, the default option of
     [1mbentover [22mwill turn it visible in this case.  If you don't want
     that, you may choose [1mnobentover [22minstead.  See also hidden line
     removal demo (hidden.dem) and complex hidden line demo (sin-
     gulr.dem).



     [1m45.26.  Historysize[0m


     Note: the command [1mset historysize [22mis only available when gnu-
     plot has been configured with the GNU readline.

     Syntax:
           set historysize <int>
           unset historysize

     When leaving gnuplot, the value of historysize is used for
     truncating the history to at most that much lines. The default
     is 500.  [1munset historysize [22mwill disable history truncation and
     thus allow an infinite number of lines to be written to the
     history file.



     [1m45.27.  Isosamples[0m


     The isoline density (grid) for plotting functions as surfaces
     may be changed by the [1mset isosamples [22mcommand.

     Syntax:
           set isosamples <iso_1> {,<iso_2>}
           show isosamples

     Each function surface plot will have <iso_1> iso-u lines and
     <iso_2> iso-v lines.  If you only specify <iso_1>, <iso_2> will
     be set to the same value as <iso_1>.  By default, sampling is
     set to 10 isolines per u or v axis.  A higher sampling rate
     will produce more accurate plots, but will take longer.  These
     parameters have no effect on data file plotting.

     An isoline is a curve parameterized by one of the surface
     parameters while the other surface parameter is fixed.  Iso-
     lines provide a simple means to display a surface.  By fixing
     the u parameter of surface s(u,v), the iso-u lines of the form
     c(v) = s(u0,v) are produced, and by fixing the v parameter, the
     iso-v lines of the form c(u) = s(u,v0) are produced.

     When a function surface plot is being done without the removal
     of hidden lines, [1mset samples  [22mcontrols the number of points
     sampled along each isoline;  see [1mset samples [22mand [1mset hidden3d[22m.










GNUPLOT 4.1                                                      127


     The contour algorithm assumes that a function sample occurs at
     each isoline intersection, so change in [1msamples [22mas well as
     [1misosamples [22mmay be desired when changing the resolution of a
     function surface/contour.



     [1m45.28.  Key[0m


     The [1mset key [22menables a key (or legend) describing plots on a
     plot.

     The contents of the key, i.e., the names given to each plotted
     data set and function and samples of the lines and/or symbols
     used to represent them, are determined by the [1mtitle [22mand [1mwith[0m
     options of the {[1ms[22m}[1mplot [22mcommand.  Please see [1mplot title [22mand [1mplot[0m
     [1mwith [22mfor more information.

     Syntax:
           set key {on|off} {default}
                   {{inside | outside} | {lmargin | rmargin | tmar-
     gin | bmargin}
                     | {at <position>}}
                   {left | right | center} {top | bottom | center}
                   {vertical | horizontal} {Left | Right}
                   {{no}reverse} {{no}invert}
                   {samplen <sample_length>} {spacing <verti-
     cal_spacing>}
                   {width <width_increment>}
                   {height <height_increment>}
                   {{no}autotitle {columnheader}}
                   {title "<text>"} {{no}enhanced}
                   {{no}box { {linestyle | ls <line_style>}
                              | {linetype | lt <line_type>}
                                {linewidth | lw <line_width>}}}
           unset key
           show key

     Plots may be drawn with no visible key by requesting [1mset key[0m
     [1moff [22mor [1munset key[22m.

     Elements within the key are stacked according to [1mvertical [22mor
     [1mhorizontal[22m.  In the case of [1mvertical[22m, the key occupies as few
     columns as possible.  That is, elements are aligned in a column
     until running out of vertical space at which point a new column
     is started.  In the case of [1mhorizontal[22m, the key occupies as few
     rows as possible.

     By default the key is placed in the upper right inside corner
     of the graph.  The keywords [1mleft[22m, [1mright[22m, [1mtop[22m, [1mbottom[22m, [1mcenter[22m,
     [1minside[22m, [1moutside[22m, [1mlmargin[22m, [1mrmargin[22m, [1mtmargin[22m, [1mbmargin [22m(, [1mabove[22m,
     [1mover[22m, [1mbelow [22mand [1munder[22m) may be used to automatically place the










GNUPLOT 4.1                                                      128


     key in other positions of the graph.  Also an [1mat <position> [22mmay
     be given to indicate precisely where the plot should be placed.
     In this case, the keywords [1mleft[22m, [1mright[22m, [1mtop[22m, [1mbottom [22mand [1mcenter[0m
     serve an analogous purpose for alignment.

     To understand positioning, the best concept is to think of a
     region, i.e., inside/outside, or one of the margins.  Along
     with the region, keywords [1mleft/center/right [22m(l/c/r) and
     [1mtop/center/bottom [22m(t/c/b) control where within the particular
     region the key should be placed.

     When in [1minside [22mmode, the keywords [1mleft [22m(l), [1mright [22m(r), [1mtop [22m(t),
     [1mbottom [22m(b), and [1mcenter [22m(c) push the key out toward the plot
     boundary as illustrated:

          t/l   t/c   t/r

          c/l    c    c/r

          b/l   b/c   b/r


     When in [1moutside [22mmode, automatic placement is similar to the
     above illustration, but with respect to the view, rather than
     the graph boundary.  That is, a border is moved inward to make
     room for the key outside of the plotting area, although this
     may interfere with other labels and may cause an error on some
     devices.  The particular plot border that is moved depends upon
     the position described above and the stacking direction.  For
     options centered in one of the dimensions, there is no ambigu-
     ity about which border to move.  For the corners, when the
     stack direction is [1mvertical[22m, the left or right border is moved
     inward appropriately.  When the stack direction is [1mhorizontal[22m,
     the top or bottom border is moved inward appropriately.

     The margin syntax allows automatic placement of key regardless
     of stack direction.  When one of the margins [1mlmargin [22m(lm),
     [1mrmargin [22m(rm), [1mtmargin [22m(tm), and [1mbmargin [22m(bm) is combined with a
     single, non-conflicting direction keyword, the following illus-
     trated positions may contain the key:

               l/tm  c/tm  r/tm

          t/lm                  t/rm

          c/lm                  c/rm

          b/lm                  b/rm

               l/bm  c/bm  r/bm


     Keywords [1mabove [22mand [1mover [22mare synonymous with [1mtmargin[22m.  For










GNUPLOT 4.1                                                      129


     version compatibility, [1mabove [22mor [1mover [22mwithout an additional
     l/c/r or stack direction keyword uses [1mcenter [22mand [1mhorizontal[22m.
     Keywords [1mbelow [22mand [1munder [22mare synonymous with [1mbmargin[22m.  For com-
     patibility, [1mbelow [22mor [1munder [22mwithout an additional l/c/r or stack
     direction keyword uses [1mcenter [22mand [1mhorizontal[22m.  A further com-
     patibility issue is that [1moutside [22mappearing without an addi-
     tional t/b/c or stack direction keyword uses [1mtop[22m, [1mright [22mand
     [1mvertical [22m(i.e., the same as t/rm above).

     The <position> can be a simple x,y,z as in previous versions,
     but these can be preceded by one of five keywords ([1mfirst[22m, [1msec-[0m
     [1mond[22m, [1mgraph[22m, [1mscreen[22m, [1mcharacter[22m) which selects the coordinate
     system in which the position of the first sample line is speci-
     fied.  See [1mcoordinates [22mfor more details.  The effect of [1mleft[22m,
     [1mright[22m, [1mtop[22m, [1mbottom[22m, and [1mcenter [22mwhen <position> is given is to
     align the key as though it were text positioned using the label
     command, i.e., [1mleft [22mmeans left align with key to the right of
     <position>, etc.

     Justification of the labels within the key is controlled by
     [1mLeft [22mor [1mRight [22m(default is [1mRight[22m).  The text and sample can be
     reversed ([1mreverse[22m) and a box can be drawn around the key ([1mbox[0m
     [1m{...}[22m) in a specified [1mlinetype [22mand [1mlinewidth[22m, or a user-defined
     [1mlinestyle[22m. Note that not all terminal drivers support linewidth
     selection, though.

     By default the first plot label is at the top of the key and
     successive labels are entered below it. The [1minvert [22moption
     causes the first label to be placed at the bottom of the key,
     with successive labels entered above it. This option is useful
     to force the vertical ordering of labels in the key to match
     the order of box types in a stacked histogram.

     The length of the sample line can be controlled by [1msamplen[22m.
     The sample length is computed as the sum of the tic length and
     <sample_length> times the character width.  [1msamplen [22malso
     affects the positions of point samples in the key since these
     are drawn at the midpoint of the sample line, even if the sam-
     ple line itself is not drawn.

     The vertical spacing between lines is controlled by [1mspacing[22m.
     The spacing is set equal to the product of the pointsize, the
     vertical tic size, and <vertical_spacing>.  The program will
     guarantee that the vertical spacing is no smaller than the
     character height.

     The <width_increment> is a number of character widths to be
     added to or subtracted from the length of the string.  This is
     useful only when you are putting a box around the key and you
     are using control characters in the text.  [1mgnuplot [22msimply
     counts the number of characters in the string when computing
     the box width; this allows you to correct it.











GNUPLOT 4.1                                                      130


     The <height_increment> is a number of character heights to be
     added to or subtracted from the height of the key box.  This is
     useful mainly when you are putting a box around the key, other-
     wise it can be used to adjust the vertical shift of automati-
     cally chosen key position by <height_increment>/2.

     All plotted curves of [1mplot[22ms and [1msplot[22ms are titled according to
     the default option [1mautotitles[22m. The automatic generation of
     titles can be suppressed by [1mnoautotitles[22m; then only those
     titles explicitly defined by [1m(s)plot ... title ... [22mwill be
     drawn.

     The [1mset key autotitle columnheader [22moption is available if gnu-
     plot was built with --enable-datastrings. This command causes
     the first entry in each column of plotted data to be inter-
     preted as a text string and used as a title for the correspond-
     ing plot. If the quantity being plotted is a function of data
     from several columns, gnuplot may be confused as to which col-
     umn to draw the title from. In this case it is necessary to
     specify the column explicitly in the plot command, e.g. [1mplot[0m
     [1m"datafile" using (($2+$3)/$4) title 3 with lines[22m.

     A title can be put on the key ([1mtitle "<text>"[22m)---see also [1msyn-[0m
     [1mtax [22mfor the distinction between text in single- or double-
     quotes.  The key title uses the same justification as do the
     plot titles.

     An explicitly given title is typeset using enhanced text prop-
     erties on terminals supporting this, see [1menhanced text [22mfor more
     details.  This default behavior can be switched off by the
     [1mnoenhanced [22moption.

     The defaults for [1mset key [22mare [1mon[22m, [1mright[22m, [1mtop[22m, [1mvertical[22m, [1mRight[22m,
     [1mnoreverse[22m, [1mnoinvert[22m, [1msamplen 4[22m, [1mspacing 1.25[22m, [1mtitle ""[22m, and
     [1mnobox[22m.  The default <linetype> is the same as that used for the
     plot borders.  Entering [1mset key default [22mreturns the key to its
     default configuration.

     The key is drawn as a sequence of lines, with one plot
     described on each line.  On the right-hand side (or the left-
     hand side, if [1mreverse [22mis selected) of each line is a represen-
     tation that attempts to mimic the way the curve is plotted.  On
     the other side of each line is the text description (the line
     title), obtained from the [1mplot [22mcommand.  The lines are verti-
     cally arranged so that an imaginary straight line divides the
     left- and right-hand sides of the key.  It is the coordinates
     of the top of this line that are specified with the [1mset key[0m
     command.  In a [1mplot[22m, only the x and y coordinates are used to
     specify the line position.  For a [1msplot[22m, x, y and z are all
     used as a 3-d location mapped using the same mapping as the
     graph itself to form the required 2-d screen position of the
     imaginary line.











GNUPLOT 4.1                                                      131


     When using the TeX or PostScript drivers, or similar drivers
     where formatting information is embedded in the string, [1mgnuplot[0m
     is unable to calculate correctly the width of the string for
     key positioning.  If the key is to be positioned at the left,
     it may be convenient to use the combination  [1mset key left Left[0m
     [1mreverse[22m.  The box and gap in the grid will be the width of the
     literal string.

     If [1msplot [22mis being used to draw contours, the contour labels
     will be listed in the key.  If the alignment of these labels is
     poor or a different number of decimal places is desired, the
     label format can be specified.  See [1mset clabel [22mfor details.

     Examples:

     This places the key at the default location:
           set key default

     This disables the key:
           unset key

     This places a key at coordinates 2,3.5,2 in the default (first)
     coordinate system:
           set key at 2,3.5,2

     This places the key below the graph:
           set key below

     This places the key in the bottom left corner, left-justifies
     the text, gives it a title, and draws a box around it in line-
     type 3:
           set key left bottom Left title 'Legend' box 3



     [1m45.29.  Label[0m


     Arbitrary labels can be placed on the plot using the [1mset label[0m
     command.

     Syntax:
           set label {<tag>} {"<label text>"} {at <position>}
                     {left | center | right}
                     {norotate | rotate {by <degrees>}}
                     {font "<name>{,<size>}"}
                     {noenhanced}
                     {front | back}
                     {textcolor <colorspec>}
                     {point <pointstyle> | nopoint}
                     {offset <offset>}
           unset label {<tag>}
           show label










GNUPLOT 4.1                                                      132


     The <position> is specified by either x,y or x,y,z, and may be
     preceded by [1mfirst[22m, [1msecond[22m, [1mgraph[22m, [1mscreen[22m, or [1mcharacter [22mto
     select the coordinate system.  See [1mcoordinates [22mfor details.

     The tag is an integer that is used to identify the label. If no
     <tag> is given, the lowest unused tag value is assigned auto-
     matically.  The tag can be used to delete or modify a specific
     label.  To change any attribute of an existing label, use the
     [1mset label [22mcommand with the appropriate tag, and specify the
     parts of the label to be changed.

     The <label text> can be a string constant, a string variable,
     or a string- valued expression. See [1mstrings[22m, [1msprintf[22m, and
     [1mgprintf[22m.

     By default, the text is placed flush left against the point
     x,y,z.  To adjust the way the label is positioned with respect
     to the point x,y,z, add the justification parameter, which may
     be [1mleft[22m, [1mright [22mor [1mcenter[22m, indicating that the point is to be at
     the left, right or center of the text.  Labels outside the
     plotted boundaries are permitted but may interfere with axis
     labels or other text.

     If [1mrotate [22mis given, the label is written vertically (if the
     terminal can do so, of course).  If [1mrotate by <degrees> [22mis
     given, conforming terminals will try to write the text at the
     specified angle; non-conforming terminals will treat this as
     vertical text.

     Font and its size can be chosen explicitly by [1mfont[0m
     [1m"<name>{,<size>}" [22mif the terminal supports font settings.  Oth-
     erwise the default font of the terminal will be used.

     Normally the enhanced text mode string interpretation, if
     enabled for the current terminal, is applied to all text
     strings including label text.  The [1mnoenhanced [22mproperty can be
     used to exempt a specific label from the enhanced text mode
     processing.  The can be useful if the label contains under-
     scores, for example. See [1menhanced text[22m.

     If [1mfront [22mis given, the label is written on top of the graphed
     data. If [1mback [22mis given (the default), the label is written
     underneath the graphed data.  Using [1mfront [22mwill prevent a label
     from being obscured by dense data.

     [1mTextcolor <colorspec> [22mchanges the color of the label text.
     [1m<colorspec> [22mis either a linetype or a mapping onto the pm3d
     color palette (available only in [1msplot[22m), see help for [1mset[0m
     [1mpalette[22m.
        `textcolor` may be abbreviated `tc`.
        `tc default` resets the text color to its default state.
        `tc lt <n>` sets the text color to that of line type <n>.
        `tc ls <n>` sets the text color to that of line style <n>.










GNUPLOT 4.1                                                      133


        `tc palette z` selects a palette color corresponding to the
     label z position.
        `tc palette cb <val>` selects a color corresponding to <val>
     on the colorbar.
        `tc palette fraction <val>`, with 0<=val<=1, selects a color
     corresponding to
            the mapping [0:1] to grays/colors of the `palette`.

     If a <pointstyle> is given, using keywords [1mlt[22m, [1mpt [22mand [1mps[22m, see
     [1mstyle[22m, a point with the given style and color of the given line
     type is plotted at the label position and the text of the label
     is displaced slightly.  This option is used by default for
     placing labels in [1mmouse [22menhanced terminals.  Use [1mnopoint [22mto
     turn off the drawing of a point near the label (this is the
     default).

     The displacement defaults to 1,1 in [1mpointsize [22munits if a
     <pointstyle> is given, 0,0 if no <pointstyle> is given.  The
     displacement can be controlled by the optional [1moffset <offset>[0m
     where <offset> is specified by either x,y or x,y,z, and may be
     preceded by [1mfirst[22m, [1msecond[22m, [1mgraph[22m, [1mscreen[22m, or [1mcharacter [22mto
     select the coordinate system.  See [1mcoordinates [22mfor details.

     If one (or more) axis is timeseries, the appropriate coordinate
     should be given as a quoted time string according to the
     [1mtimefmt [22mformat string.  See [1mset xdata [22mand [1mset timefmt[22m.

     The EEPIC, Imagen, LaTeX, and TPIC drivers allow \\ in a string
     to specify a newline.

     Examples:

     To set a label at (1,2) to "y=x", use:
           set label "y=x" at 1,2

     To set a Sigma of size 24, from the Symbol font set, at the
     center of the graph, use:
           set label "S" at graph 0.5,0.5 center font "Symbol,24"

     To set a label "y=x^2" with the right of the text at (2,3,4),
     and tag the label as number 3, use:
           set label 3 "y=x^2" at 2,3,4 right

     To change the preceding label to center justification, use:
           set label 3 center

     To delete label number 2, use:
           unset label 2

     To delete all labels, use:
           unset label

     To show all labels (in tag order), use:










GNUPLOT 4.1                                                      134


           show label

     To set a label on a graph with a timeseries on the x axis, use,
     for example:
           set timefmt "%d/%m/%y,%H:%M"
           set label "Harvest" at "25/8/93",1

     To display a freshly fitted parameter on the plot with the data
     and the fitted function, do this after the [1mfit[22m, but before the
     [1mplot[22m:
           set label sprintf("a = %3.5g",par_a) at 30,15
           bfit = gprintf("b = %s*10^%S",par_b)
           set label bfit at 30,20

     To set a label displaced a little bit from a small point:
           set label 'origin' at 0,0 point lt 1 pt 2 ps 3 offset
     1,-1

     To set a label whose color matches the z value (in this case
     5.5) of some point on a 3D splot colored using pm3d:
           set label 'text' at 0,0,5.5 tc palette z




     [1m45.30.  Lmargin[0m


     The command [1mset lmargin [22msets the size of the left margin.
     Please see [1mset margin [22mfor details.



     [1m45.31.  Loadpath[0m


     The [1mloadpath [22msetting defines additional locations for data and
     command files searched by the [1mcall[22m, [1mload[22m, [1mplot [22mand [1msplot [22mcom-
     mands.  If a file cannot be found in the current directory, the
     directories in [1mloadpath [22mare tried.

     Syntax:
           set loadpath {"pathlist1" {"pathlist2"...}}
           show loadpath

     Path names may be entered as single directory names, or as a
     list of path names separated by a platform-specific path sepa-
     rator, eg. colon (':') on Unix, semicolon (';') on DOS/Win-
     dows/OS/2/Amiga platforms.  The [1mshow loadpath[22m, [1msave [22mand [1msave[0m
     [1mset [22mcommands replace the platform-specific separator with a
     space character (' ') for maximum portability.

     If the environment variable GNUPLOT_LIB is set, its contents










GNUPLOT 4.1                                                      135


     are appended to [1mloadpath[22m.  However, [1mshow loadpath [22mprints the
     contents of user defined loadpath and system loadpath sepa-
     rately.  Also, the [1msave [22mand [1msave set [22mcommands save only the
     user specified parts of [1mloadpath[22m, for portability reasons.



     [1m45.32.  Locale[0m


     The [1mlocale [22msetting determines the language with which
     [1m{x,y,z}{d,m}tics [22mwill write the days and months.

     Syntax:
           set locale {"<locale>"}

     <locale> may be any language designation acceptable to your
     installation.  See your system documentation for the available
     options.  The default value is determined from the LC_TIME,
     LC_ALL, or LANG environment variables.

     To change the decimal point locale, see [1mset decimalsign[22m.



     [1m45.33.  Logscale[0m


     Syntax:
           set logscale <axes> <base>
           unset logscale <axes>
           show logscale

     where <axes> may be any combination of [1mx[22m, [1mx2[22m, [1my[22m, [1my2[22m, [1mz[22m, and [1mcb[0m
     in any order, and where <base> is the base of the log scaling.
     If <base> is not given, then 10 is assumed.  If <axes> is not
     given, then all axes are assumed.  [1munset logscale [22mturns off log
     scaling for the specified axes.

     Examples:

     To enable log scaling in both x and z axes:
           set logscale xz

     To enable scaling log base 2 of the y axis:
           set logscale y 2

     To enable z and color log axes for a pm3d plot:
           set logscale zcb

     To disable z axis log scaling:
           unset logscale z











GNUPLOT 4.1                                                      136


     [1m45.34.  Macros[0m


     If command line macro substitution is enabled, then tokens in
     the command line of the form @<stringvariablename> will be
     replaced by the text string contained in <stringvariablename>.
     See [1msubstitution[22m.

     Syntax:
          set macros




     [1m45.35.  Mapping[0m


     If data are provided to [1msplot [22min spherical or cylindrical coor-
     dinates, the [1mset mapping [22mcommand should be used to instruct
     [1mgnuplot [22mhow to interpret them.

     Syntax:
           set mapping {cartesian | spherical | cylindrical}

     A cartesian coordinate system is used by default.

     For a spherical coordinate system, the data occupy two or three
     columns (or [1musing [22mentries).  The first two are interpreted as
     the azimuthal and polar angles theta and phi (or "longitude"
     and "latitude"), in the units specified by [1mset angles[22m.  The
     radius r is taken from the third column if there is one, or is
     set to unity if there is no third column.  The mapping is:

           x = r * cos(theta) * cos(phi)
           y = r * sin(theta) * cos(phi)
           z = r * sin(phi)

     Note that this is a "geographic" spherical system, rather than
     a "polar" one (that is, phi is measured from the equator,
     rather than the pole).

     For a cylindrical coordinate system, the data again occupy two
     or three columns.  The first two are interpreted as theta (in
     the units specified by [1mset angles[22m) and z.  The radius is either
     taken from the third column or set to unity, as in the spheri-
     cal case.  The mapping is:

           x = r * cos(theta)
           y = r * sin(theta)
           z = z

     The effects of [1mmapping [22mcan be duplicated with the [1musing [22mfilter
     on the [1msplot [22mcommand, but [1mmapping [22mmay be more convenient if










GNUPLOT 4.1                                                      137


     many data files are to be processed.  However even if [1mmapping[0m
     is used, [1musing [22mmay still be necessary if the data in the file
     are not in the required order.

     [1mmapping [22mhas no effect on [1mplot[22m.  world.dem: mapping demos.



     [1m45.36.  Margin[0m


     The computed margins can be overridden by the [1mset margin [22mcom-
     mands.  [1mshow margin [22mshows the current settings.

     Syntax:
           set bmargin {<margin>}
           set lmargin {<margin>}
           set rmargin {<margin>}
           set tmargin {<margin>}
           show margin

     The units of <margin> are character heights or widths, as
     appropriate.  A positive value defines the absolute size of the
     margin.  A negative value (or none) causes [1mgnuplot [22mto revert to
     the computed value.  For 3D plots, only the left margin setting
     has any effect so far.

     Normally the margins of a plot are automatically calculated
     based on tics, tic labels, axis labels, the plot title, the
     timestamp and the size of the key if it is outside the borders.
     If, however, tics are attached to the axes ([1mset xtics axis[22m, for
     example), neither the tics themselves nor their labels will be
     included in either the margin calculation or the calculation of
     the positions of other text to be written in the margin.  This
     can lead to tic labels overwriting other text if the axis is
     very close to the border.



     [1m45.37.  Mouse[0m


     The command [1mset mouse [22menables mouse actions. Currently the pm,
     x11, ggi, windows and wxt terminals are mouse enhanced. There
     are two mouse modes. The 2d-graph mode works for 2d graphs and
     for maps (i.e. splots with [1mset view [22mhaving z-rotation 0, 90,
     180, 270 or 360 degrees, including [1mset view map[22m) and it allows
     tracing the position over graph, zooming, annotating graph etc.
     For 3d graphs [1msplot[22m, the view and scaling of the graph can be
     changed with mouse buttons 1 and 2. If additionally to these
     buttons the modifier <ctrl> is hold down, the coordinate system
     only is rotated which is useful for large data sets. A vertical
     motion of Button 2 with the shift key hold down changes the










GNUPLOT 4.1                                                      138


     [1mticslevel[22m.

     Mousing is not available in multiplot mode. When multiplot is
     finished using [1munset multiplot[22m, then the mouse will be turned
     on again and acts on the last plot (like replot does).

     Syntax:
           set mouse {doubleclick <ms>} {nodoubleclick} \
                     {{no}zoomcoordinates} \
                     {noruler | ruler {at x,y}} \
                     {polardistance{deg|tan} | nopolardistance} \
                     {format <string>} \
                     {clipboardformat <int>/<string>} \
                     {mouseformat <int>/<string>} \
                     {{no}labels} {labeloptions <string>} \
                     {{no}zoomjump} {{no}verbose}
           unset mouse

     The doubleclick resolution is given in milliseconds and used
     for Button 1 which copies the current mouse position to the
     [1mclipboard[22m. If you want that to be done by single clicking a
     value of 0 ms can be used. The default value is 300 ms.

     The option [1mzoomcoordinates [22mdetermines if the coordinates of the
     zoom box are drawn at the edges while zooming. This is on by
     default.

     The options [1mnoruler [22mand [1mruler [22mswitch the ruler off and on, the
     latter optionally at given [1mcoordinates[22m. This corresponds to the
     default key binding 'r'.

     The option [1mpolardistance [22mdetermines if the distance between the
     mouse cursor and the ruler is also shown in polar coordinates
     (distance and angle in degrees or tangent (slope)). This corre-
     sponds to the default key binding '5'.

     The [1mformat [22moption takes a fprintf like format string which
     determines how floating point numbers are printed to the
     drivers window and the clipboard.  The default is "% #g".

     [1mclipboardformat [22mand [1mmouseformat [22mare used for formatting the
     text on Button1 and Button2 actions -- copying the coordinates
     to the clipboard and temporarily annotating the mouse position.
     This corresponds to the key bindings '1', '2', '3', '4' (see
     the drivers's help window). If the argument is a string this
     string is used as c format specifier and should contain two
     float specifiers, e.g. [1mset mouse mouseformat "mouse = %5.2g,[0m
     [1m%10.2f"[22m. Use [1mset mouse mouseformat "" [22mto turn this string off
     again.

     The following formats are available (format 6 may only be
     selected if the format string was specified already):











GNUPLOT 4.1                                                      139


      0   real coordinates in  brackets e.g. [1.23, 2.45]
      1   real coordinates w/o brackets e.g.  1.23, 2.45
      2   x == timefmt                       [(as set by `set
     timefmt`), 2.45]
      3   x == date                          [31. 12. 1999, 2.45]
      4   x == time                          [23:59, 2.45]
      5   x == date / time                   [31. 12. 1999 23:59,
     2.45]
      6   alt. format, specified as string   ""

     Choose the option [1mlabels [22mto get real gnuplot labels on Button
     2. (The default is [1mnolabels [22mwhich makes Button 2 drawing only
     temporary annotations at the mouse positions). The labels are
     drawn with the current setting of [1mmouseformat[22m. [1mlabeloptions[0m
     controls which options are passed to the [1mset label [22mcommand. The
     default is "pointstyle 1" which will plot a small plus at the
     label position.  Note that the pointsize is taken from the [1mset[0m
     [1mpointsize [22mcommand.  Labels can be removed by holding the Ctrl-
     Key down while clicking with Button 2 on the label's point. The
     threshold for how close you must be to the label is also deter-
     mined by the [1mpointsize[22m.

     If the option [1mzoomjump [22mis on, the mouse pointer will be auto-
     matically offset a small distance after starting a zoom region
     with button 3. This can be useful to avoid a tiny (or even
     empty) zoom region. [1mzoomjump [22mis off by default.

     If the option [1mverbose [22mis turned on the communication commands
     are shown during execution. This option can also be toggled by
     hitting [1m6 [22min the driver's window. [1mverbose [22mis off by default.

     Press 'h' in the driver's window for a short summary of the
     mouse and key bindings.  This will also display user defined
     bindings or [1mhotkeys [22mwhich can be defined using the [1mbind [22mcom-
     mand, see help for [1mbind[22m.  Note, that user defined [1mhotkeys [22mmay
     override the default bindings.

     Press 'q' in the driver's window to close the window. This key
     cannot be overridden with the [1mbind [22mcommand.

     See also help for [1mbind [22mand [1mlabel[22m.




          [1m45.37.1.  X11 mouse[0m


          If multiple X11 plot windows have been opened using the
          [1mset term x11 <n> [22mterminal option, then only the current
          plot window supports the entire range of mouse commands
          and hotkeys.  The other windows will, however, continue to
          display mouse coordinates at the lower left.










GNUPLOT 4.1                                                      140


          For consistency with other screen terminals, X11 mouse
          support is turned on by default, wherever the standard
          input comes from. However, on some UNIX flavors, special
          input devices as /dev/null might not be [1mselect-able[22m; using
          such devices with the mouse turned on will hang gnuplot.
          Please turn off mousing with [1munset mouse [22mif you are in
          this situation.



     [1m45.38.  Multiplot[0m


     The command [1mset multiplot [22mplaces [1mgnuplot [22min the multiplot mode,
     in which several plots are placed on the same page, window, or
     screen.

     Syntax:
           set multiplot { layout <rows>,<cols>
                           {rowsfirst|columnsfirst} {down-
     wards|upwards}
                           {title <page title>}
                           {scale <xscale>{,<yscale>}} {offset
     <xoff>{,<yoff>}}
                         }
           unset multiplot

     For some terminals, no plot is displayed until the command
     [1munset multiplot [22mis given, which causes the entire page to be
     drawn and then returns gnuplot to its normal single-plot mode.
     For other terminals, each separate [1mplot [22mcommand produces an
     updated display, either by redrawing all previous ones and the
     newly added plot, or by just adding the new plot to the exist-
     ing display.

     The area to be used by the next plot is not erased before doing
     the new plot.  The [1mclear [22mcommand can be used to do this if
     wanted, as is typically the case for "inset" plots.

     Any labels or arrows that have been defined will be drawn for
     each plot according to the current size and origin (unless
     their coordinates are defined in the [1mscreen [22msystem).  Just
     about everything else that can be [1mset [22mis applied to each plot,
     too.  If you want something to appear only once on the page,
     for instance a single time stamp, you'll need to put a [1mset[0m
     [1mtime[22m/[1munset time [22mpair around one of the [1mplot[22m, [1msplot [22mor [1mreplot[0m
     commands within the [1mset multiplot[22m/[1munset multiplot [22mblock.

     The multiplot title is distinct from the individual plot
     titles, if any.  Space is reserved for it at the top of the
     page, spanning the full width of the canvas.

     The commands [1mset origin [22mand [1mset size [22mmust be used to correctly










GNUPLOT 4.1                                                      141


     position each plot if no [1mlayout [22mis specified or if fine tuning
     is desired.  See [1mset origin [22mand [1mset size [22mfor details of their
     usage.

     Example:
           set multiplot
           set size 0.4,0.4
           set origin 0.1,0.1
           plot sin(x)
           set size 0.2,0.2
           set origin 0.5,0.5
           plot cos(x)
           unset multiplot

     This displays a plot of cos(x) stacked above a plot of sin(x).

     [1mset size [22mand [1mset origin [22mrefer to the entire plotting area used
     for each plot.  Please also see [1mset term size[22m.  If you want to
     have the axes themselves line up, you can guarantee that the
     margins are the same size with the [1mset margin [22mcommands.  See
     [1mset margin [22mfor their use.  Note that the margin settings are
     absolute, in character units, so the appearance of the graph in
     the remaining space will depend on the screen size of the dis-
     play device, e.g., perhaps quite different on a video display
     and a printer.

     With the [1mlayout [22moption you can generate simple multiplots with-
     out having to give the [1mset size [22mand [1mset origin [22mcommands before
     each plot:  Those are generated automatically, but can be over-
     ridden at any time.  With [1mlayout [22mthe display will be divided by
     a grid with <rows> rows and <cols> columns.  This grid is
     filled rows first or columns first depending on whether the
     corresponding option is given in the multiplot command.  The
     stack of plots can grow [1mdownwards [22mor [1mupwards[22m.  Default is [1mrows-[0m
     [1mfirst [22mand [1mdownwards[22m.

     Each plot can be scaled by [1mscale [22mand shifted with [1moffset[22m; if
     the y-values for scale or offset are omitted, the x-value will
     be used.  [1munset multiplot [22mwill turn off the automatic layout
     and restore the values of [1mset size [22mand [1mset origin [22mas they were
     before [1mset multiplot layout[22m.

     Example:
           set size 1,1
           set origin 0,0
           set multiplot layout 3,2 columnsfirst scale 1.1,0.9
           [ up to 6 plot commands here ]
           unset multiplot

     The above example will produce 6 plots in 2 columns filled top
     to bottom, left to right.  Each plot will have a horizontal
     size of 1.1/2 and a vertical size of 0.9/3.











GNUPLOT 4.1                                                      142


     See also multiplot demo (multiplt.dem)



     [1m45.39.  Mx2tics[0m


     Minor tic marks along the x2 (top) axis are controlled by [1mset[0m
     [1mmx2tics[22m.  Please see [1mset mxtics[22m.



     [1m45.40.  Mxtics[0m


     Minor tic marks along the x axis are controlled by [1mset mxtics[22m.
     They can be turned off with [1munset mxtics[22m.  Similar commands
     control minor tics along the other axes.

     Syntax:
           set mxtics {<freq> | default}
           unset mxtics
           show mxtics

     The same syntax applies to [1mmytics[22m, [1mmztics[22m, [1mmx2tics[22m, [1mmy2tics [22mand
     [1mmcbtics[22m.

     <freq> is the number of sub-intervals (NOT the number of minor
     tics) between major tics (the default for a linear axis is
     either two or five depending on the major tics, so there are
     one or four minor tics between major tics). Selecting [1mdefault[0m
     will return the number of minor ticks to its default value.

     If the axis is logarithmic, the number of sub-intervals will be
     set to a reasonable number by default (based upon the length of
     a decade).  This will be overridden if <freq> is given.  How-
     ever the usual minor tics (2, 3, ..., 8, 9 between 1 and 10,
     for example) are obtained by setting <freq> to 10, even though
     there are but nine sub-intervals.

     To set minor tics at arbitrary positions, use the ("<label>"
     <pos> <level>, ...) form of [1mset {x|x2|y|y2|z}tics [22mwith <label>
     empty and <level> set to 1.

     The [1mset m{x|x2|y|y2|z}tics [22mcommands work only when there are
     uniformly spaced major tics.  If all major tics were placed
     explicitly by [1mset {x|x2|y|y2|z}tics[22m, then minor tic commands
     are ignored.  Implicit major tics and explicit minor tics can
     be combined using [1mset {x|x2|y|y2|z}tics [22mand [1mset[0m
     [1m{x|x2|y|y2|z}tics add[22m.

     Examples:
           set xtics 0, 5, 10










GNUPLOT 4.1                                                      143


           set xtics add (7.5)
           set mxtics 5
     Major tics at 0,5,7.5,10, minor tics at 1,2,3,4,6,7,8,9
           set logscale y
           set format y ""
           set ytics 1e-6, 10, 1
           set ytics add ("1" 1, ".1" 0.1, ".01" 0.01, "10^-3"
     0.001, \
                          "10^-4" 0.0001)
           set mytics 10
     Major tics with special formatting, minor tics at log positions

     By default, minor tics are off for linear axes and on for loga-
     rithmic axes.  They inherit the settings for [1maxis|border [22mand
     [1m{no}mirror [22mspecified for the major tics.  Please see [1mset xtics[0m
     for information about these.



     [1m45.41.  My2tics[0m


     Minor tic marks along the y2 (right-hand) axis are controlled
     by [1mset my2tics[22m.  Please see [1mset mxtics[22m.



     [1m45.42.  Mytics[0m


     Minor tic marks along the y axis are controlled by [1mset mytics[22m.
     Please see [1mset mxtics[22m.



     [1m45.43.  Mztics[0m


     Minor tic marks along the z axis are controlled by [1mset mztics[22m.
     Please see [1mset mxtics[22m.



     [1m45.44.  Offsets[0m


     Offsets provide a mechanism to put a boundary around the data
     inside of an autoscaled graph.

     Syntax:
           set offsets <left>, <right>, <top>, <bottom>
           unset offsets
           show offsets










GNUPLOT 4.1                                                      144


     Each offset may be a constant or an expression.  Each defaults
     to 0.  Left and right offsets are given in units of the x axis,
     top and bottom offsets in units of the y axis.  A positive off-
     set expands the graph in the specified direction, e.g., a posi-
     tive bottom offset makes ymin more negative.  Negative offsets,
     while permitted, can have unexpected interactions with
     autoscaling and clipping.

     Offsets are ignored in [1msplot[22ms.

     Example:
           set offsets 0, 0, 2, 2
           plot sin(x)

     This graph of sin(x) will have a y range [-3:3] because the
     function will be autoscaled to [-1:1] and the vertical offsets
     are each two.



     [1m45.45.  Origin[0m


     The [1mset origin [22mcommand is used to specify the origin of a plot-
     ting surface (i.e., the graph and its margins) on the screen.
     The coordinates are given in the [1mscreen [22mcoordinate system (see
     [1mcoordinates [22mfor information about this system).

     Syntax:
           set origin <x-origin>,<y-origin>



     [1m45.46.  Output[0m


     By default, screens are displayed to the standard output. The
     [1mset output [22mcommand redirects the display to the specified file
     or device.

     Syntax:
           set output {"<filename>"}
           show output

     The filename must be enclosed in quotes.  If the filename is
     omitted, any output file opened by a previous invocation of [1mset[0m
     [1moutput [22mwill be closed and new output will be sent to STDOUT.
     (If you give the command [1mset output "STDOUT"[22m, your output may
     be sent to a file named "STDOUT"!  ["May be", not "will be",
     because some terminals, like [1mx11 [22mor [1mwxt[22m, ignore [1mset output[22m.])

     MSDOS users should note that the \ character has special sig-
     nificance in double-quoted strings, so single-quotes should be










GNUPLOT 4.1                                                      145


     used for filenames in different directories.

     When both [1mset terminal [22mand [1mset output [22mare used together, it is
     safest to give [1mset terminal [22mfirst, because some terminals set a
     flag which is needed in some operating systems.  This would be
     the case, for example, if the operating system needs to know
     whether or not a file is to be formatted in order to open it
     properly.

     On machines with popen functions (Unix), output can be piped
     through a shell command if the first non-whitespace character
     of the filename is '|'.  For instance,

           set output "|lpr -Plaser filename"
           set output "|lp -dlaser filename"

     On MSDOS machines, [1mset output "PRN" [22mwill direct the output to
     the default printer.  On VMS, output can be sent directly to
     any spooled device.  It is also possible to send the output to
     DECnet transparent tasks, which allows some flexibility.



     [1m45.47.  Parametric[0m


     The [1mset parametric [22mcommand changes the meaning of [1mplot [22m([1msplot[22m)
     from normal functions to parametric functions.  The command
     [1munset parametric [22mrestores the plotting style to normal, single-
     valued expression plotting.

     Syntax:
           set parametric
           unset parametric
           show parametric

     For 2-d plotting, a parametric function is determined by a pair
     of parametric functions operating on a parameter.  An example
     of a 2-d parametric function would be [1mplot sin(t),cos(t)[22m, which
     draws a circle (if the aspect ratio is set correctly---see [1mset[0m
     [1msize[22m).  [1mgnuplot [22mwill display an error message if both functions
     are not provided for a parametric [1mplot[22m.

     For 3-d plotting, the surface is described as x=f(u,v),
     y=g(u,v), z=h(u,v).  Therefore a triplet of functions is
     required.  An example of a 3-d parametric function would be
     [1mcos(u)*cos(v),cos(u)*sin(v),sin(u)[22m, which draws a sphere.  [1mgnu-[0m
     [1mplot [22mwill display an error message if all three functions are
     not provided for a parametric [1msplot[22m.

     The total set of possible plots is a superset of the simple
     f(x) style plots, since the two functions can describe the x
     and y values to be computed separately.  In fact, plots of the










GNUPLOT 4.1                                                      146


     type t,f(t) are equivalent to those produced with f(x) because
     the x values are computed using the identity function.  Simi-
     larly, 3-d plots of the type u,v,f(u,v) are equivalent to
     f(x,y).

     Note that the order the parametric functions are specified is
     xfunction, yfunction (and zfunction) and that each operates
     over the common parametric domain.

     Also, the [1mset parametric [22mfunction implies a new range of val-
     ues.  Whereas the normal f(x) and f(x,y) style plotting assume
     an xrange and yrange (and zrange), the parametric mode addi-
     tionally specifies a trange, urange, and vrange.  These ranges
     may be set directly with [1mset trange[22m, [1mset urange[22m, and [1mset[0m
     [1mvrange[22m, or by specifying the range on the [1mplot [22mor [1msplot [22mcom-
     mands.  Currently the default range for these parametric vari-
     ables is [-5:5].  Setting the ranges to something more meaning-
     ful is expected.



     [1m45.48.  Plot[0m


     The [1mshow plot [22mcommand shows the current plotting command as it
     results from the last [1mplot [22mand/or [1msplot [22mand possible subsequent
     [1mreplot [22mcommands.

     In addition, the [1mshow plot add2history [22mcommand adds this cur-
     rent plot command into the [1mhistory[22m. It is useful if you have
     used [1mreplot [22mto add more curves to the current plot and you want
     to edit the whole command now.



     [1m45.49.  Pm3d[0m


     pm3d is an [1msplot [22mstyle for drawing palette-mapped 3d and 4d
     data as color/gray maps and surfaces.  It uses a pm3d algorithm
     which allows plotting gridded as well as non-gridded data with-
     out preprocessing, even when the data scans do not have the
     same number of points.

     Drawing of color surfaces is available on terminals supporting
     filled colored polygons with color mapping specified by
     [1mpalette[22m. Currently supported terminals include

       Screen terminals:
         OS/2 Presentation Manager
         X11
         Linux VGA (vgagl)
         GGI










GNUPLOT 4.1                                                      147


         Windows
         AquaTerm (Mac OS X)
         wxWidgets (wxt)
       Files:
         PostScript
         pslatex, pstex, epslatex
         gif, png, jpeg
         (x)fig
         tgif
         cgm
         pdf
         svg

     Let us first describe how a map/surface is drawn.  The input
     data come from an evaluated function or from an [1msplot data[0m
     [1mfile[22m.  Each surface consists of a sequence of separate scans
     (isolines).  The pm3d algorithm fills the region between two
     neighbouring points in one scan with another two points in the
     next scan by a gray (or color) according to z-values (or
     according to an additional 'color' column, see help for [1musing[22m)
     of these 4 corners; by default the 4 corner values are aver-
     aged, but this can be changed by the option [1mcorners2color[22m.  In
     order to get a reasonable surface, the neighbouring scans
     should not cross and the number of points in the neighbouring
     scans should not differ too much; of course, the best plot is
     with scans having same number of points.  There are no other
     requirements (e.g. the data need not be gridded).  Another
     advantage is that the pm3d algorithm does not draw anything
     outside of the input (measured or calculated) region.

     Surface coloring works with the following input data:

     1. splot of function or of data file with one or three data
     columns: The gray/color scale is obtained by mapping the aver-
     aged (or [1mcorners2color[22m) z-coordinate of the four corners of the
     above-specified quadrangle into the range
     [min_color_z,max_color_z] of [1mzrange [22mor [1mcbrange [22mproviding a gray
     value in the range [0:1].  This value can be used directly as
     the gray for gray maps.  The normalized gray value can be fur-
     ther mapped into a color---see [1mset palette [22mfor the complete
     description.

     2. splot of data file with two or four data columns: The
     gray/color value is obtained by using the last-column coordi-
     nate instead of the z-value, thus allowing the color and the z-
     coordinate be mutually independent.  This can be used for 4d
     data drawing.

     Other notes:

     1. The term 'scan' referenced above is used more among physi-
     cists than the term 'iso_curve' referenced in gnuplot documen-
     tation and sources.  You measure maps recorded one scan after










GNUPLOT 4.1                                                      148


     another scan, that's why.

     2. The 'gray' or 'color' scale is a linear mapping of a contin-
     uous variable onto a smoothly varying palette of colors. The
     mapping is shown in a rectangle next to the main plot. This
     documentation refers to this as a "colorbox", and refers to the
     indexing variable as lying on the colorbox axis.  See [1mset col-[0m
     [1morbox[22m, [1mset cbrange[22m.

     3. To use pm3d coloring to generate a two-dimensional plot
     rather than a 3D surface, use [1mset view map [22mor [1mset pm3d map[22m.

     Syntax (the options can be given in any order):
           set pm3d {
                      { at <bst combination> }
                      { interpolate <steps in scan>,<steps between
     scans> }
                      { scansautomatic | scansforward | scansback-
     ward | depthorder }
                      { flush { begin | center | end } }
                      { ftriangles | noftriangles }
                      { clip1in | clip4in }
                      { corners2color {
     mean|geomean|median|min|max|c1|c2|c3|c4 } }
                      { hidden3d <linestyle> | nohidden3d }
                      { implicit | explicit }
                      { map }
                    }
           show pm3d
           unset pm3d

     Color surface is drawn if data or function [1mstyle [22mis set to pm3d
     globally or via 'with' option, or if the option [1mimplicit [22mis
     on---then the pm3d surface is combined with the line surface
     mesh. See bottom of this section for mode details.

     Color surface can be drawn at the base or top (then it is a
     gray/color planar map) or at z-coordinates of surface points
     (gray/color surface).  This is defined by the [1mat [22moption with a
     string of up to 6 combinations of [1mb[22m, [1mt [22mand [1ms[22m. For instance, [1mat[0m
     [1mb [22mplots at bottom only, [1mat st [22mplots firstly surface and then
     top map, while [1mat bstbst [22mwill never by seriously used.

     Colored quadrangles are plotted one after another.  When plot-
     ting surfaces ([1mat s[22m), the later quadrangles overlap (overdraw)
     the previous ones.  (Gnuplot is not virtual reality tool to
     calculate intersections of filled polygon meshes.)  You may try
     to switch between [1mscansforward [22mand [1mscansbackward [22mto force the
     first scan of the data to be plotted first or last.  The
     default is [1mscansautomatic [22mwhere gnuplot makes a guess about
     scans order.

     If two subsequent scans do not have same number of points, then










GNUPLOT 4.1                                                      149


     it has to be decided whether to start taking points for quad-
     rangles from the beginning of both scans ([1mflush begin[22m), from
     their ends ([1mflush end[22m) or to center them ([1mflush center[22m).  Note,
     that [1mflush (center|end) [22mare incompatible with [1mscansautomatic[22m:
     if you specify [1mflush center [22mor [1mflush end [22mand [1mscansautomatic [22mis
     set, it is silently switched to [1mscansforward[22m.

     If two subsequent scans do not have the same number of points,
     the option [1mftriangles [22mspecifies whether color triangles are
     drawn at the scan tail(s) where there are not enough points in
     either of the scan. This can be used to draw a smooth map
     boundary.

     Clipping with respect to x, y coordinates of quadrangles can be
     done in two ways.  [1mclip1in[22m: all 4 points of each quadrangle
     must be defined and at least 1 point of the quadrangle must lie
     in the x and y ranges.  [1mclip4in[22m: all 4 points of each quadran-
     gle must lie in the x and y ranges.

     There is a single gray/color value associated to each drawn
     pm3d quadrangle (no smooth color change among vertices).  The
     value is calculated from z-coordinates from the surrounding
     corners according to [1mcorners2color <option>[22m.  The options
     'mean' (default), 'geomean' and 'median' produce various kinds
     of surface color smoothing, while options 'min' and 'max'
     choose minimal or maximal value, respectively. This may not be
     desired for pixel images or for maps with sharp and intense
     peaks, in which case the options 'c1', 'c2', 'c3' or 'c4' can
     be used instead to assign the quadrangle color based on the z-
     coordinate of only one corner.  Some experimentation may be
     needed to determine which corner corresponds to 'c1', as the
     orientation depends on the drawing direction.  Because the pm3d
     algorithm does not extend the colored surface outside the range
     of the input data points, the 'c<j>' coloring options will
     result in pixels along two edges of the grid not contributing
     to the color of any quadrangle.  For example, applying the pm3d
     algorithm to the 4x4 grid of data points in script
     [1mdemo/pm3d.dem [22m(please have a look) produces only (4-1)x(4-1)=9
     colored rectangles.

     Another drawing algorithm, which would draw quadrangles around
     a given node by taking corners from averaged (x,y)-coordinates
     of its surrounding 4 nodes while using node's color, could be
     implemented in the future. This is already done for drawing
     images (2D grids) via [1mimage [22mand [1mrgbimage [22mstyles.

     Notice that ranges of z-values and color-values for surfaces
     are adjustable independently by [1mset zrange[22m, [1mset cbrange[22m, as
     well as [1mset log [22mfor z or cb.  Maps can be adjusted by the cb-
     axis only; see also [1mset view map [22mand [1mset colorbox[22m.

     The option [1mhidden3d [22mtakes as the argument a linestyle which
     must be created by [1mset style line ...[22m. (The style need not to










GNUPLOT 4.1                                                      150


     be present when setting pm3d, but it must be present when plot-
     ting).  If set, lines are drawn using the specified line style,
     taking into account hidden line removal.  This is by far more
     efficient than using the command [1mset hidden3d [22mas it doesn't
     really calculate hidden line removal, but just draws the filled
     polygons in the correct order. So the recommended choice when
     using pm3d is
           set pm3d at s hidden3d 100
           set style line 100 lt 5 lw 0.5
           unset hidden3d
           unset surf
           splot x*x+y*y

     There used to be an option {transparent|solid} to this command.
     Now you get the same effect from [1mset grid {front|layerdefault}[22m,
     respectively.

     The [1mset pm3d map [22mis an abbreviation for [1mset pm3d at b[22m; [1mset view[0m
     [1mmap[22m; [1mset style data pm3d[22m; [1mset style func pm3d[22m;.  It is used for
     backwards compatibility, when [1mset view map [22mwas not available.
     Take care that you properly use [1mzrange [22mand [1mcbrange [22mfor input
     data point filtering and color range scaling, respectively; and
     also [1mset (no)surface [22mseems to have a (side?) effect.

     The option [1minterpolate [22mwill interpolate grid points into a
     finer mesh, and color each quadrangle appropriately. For data
     files, this will smoothen the color surface, and enhance spikes
     in a color surface. For functions, interpolation makes little
     sense, except to trade off precision for memory.  It would usu-
     ally make more sense to use [1msamples [22mand [1misosamples [22mwhen working
     with functions.

     The coloring setup as well as the color box drawing are deter-
     mined by [1mset palette[22m.  There can be only one palette for the
     current plot.  Drawing of several surfaces with different
     palettes can be achieved by [1mmultiplot [22mwith fixed [1morigin [22mand
     [1msize[22m; don't forget to use [1mset palette maxcolors [22mwhen your ter-
     minal is running out of available colors.

     On gnuplot start-up, mode is [1mexplicit[22m. For historical and thus
     compatibility reasons, commands [1mset pm3d; [22m(i.e. no options) and
     [1mset pm3d at X ... [22m(i.e.  [1mat [22mis the first option) sets mode
     [1mimplicit[22m. Further, [1mset pm3d; [22msets up the other options to their
     default.

     If the option [1mimplicit [22mis on, all surface plots will be plotted
     additionally to the default type, e.g.
           splot 'fred.dat' with lines, 'lola.dat' with lines
     would give both plots (meshes) additionally to a pm3d surface.
     That's what you are used to after [1mset pm3d;[22m.

     If the option [1mexplicit [22mis on (or [1mimplicit [22mis off) only plots
     specified by the [1mwith pm3d [22mattribute are plotted with a pm3d










GNUPLOT 4.1                                                      151


     surface, e.g.:
           splot 'fred.dat' with lines, 'lola.dat' with pm3d
     would plot 'fred.dat' with lines (and only lines) and
     'lola.dat' with a pm3d surface.

     If you set the default data or function style to [1mpm3d[22m, e.g.:
           set style data pm3d
     then the options [1mimplicit [22mand [1mexplicit [22mhave no effect.

     Note that when plotting several plots, they are plotted in the
     order given on the command line. This can be of interest espe-
     cially for filled surfaces which can overwrite and therefore
     hide part of earlier plots.

     If [1mwith pm3d [22mis specified in the [1msplot [22mcommand line, then it
     accepts the 'at' option.  The following plots draw three color
     surfaces at different altitudes:
           set border 4095
           set pm3d at s
           splot 10*x with pm3d at b, x*x-y*y, x*x+y*y with pm3d at
     t

     See also help for [1mset palette[22m, [1mset cbrange[22m, [1mset colorbox[22m, [1mx11[0m
     [1mpm3d [22mand definitely the demo file [1mdemo/pm3d.dem[22m.




     [1m45.50.  Palette[0m


     Palette is a color storage for use by [1mpm3d[22m, filled color con-
     tours or polygons, color histograms, color gradient background,
     and whatever it is or it will be implemented...  Here it stands
     for a palette of smooth "continuous" colors or grays, but let's
     call it just a palette.

     Color palettes require terminal entries for filled color poly-
     gons and palettes of smooth colors, are currently available for
     terminals listed in help for [1mset pm3d[22m. The range of color val-
     ues are adjustable independently by [1mset cbrange [22mand [1mset log cb[22m.
     The whole color palette is visualized in the [1mcolorbox[22m.

     Syntax:
           set palette
           set palette {
                      { gray | color }
                      { gamma <gamma> }
                      {   rgbformulae <r>,<g>,<b>
                        | defined { ( <gray1> <color1> {, <grayN>
     <colorN>}... ) }
                        | file '<filename>' {datafile-modifiers}
                        | functions <R>,<G>,<B>










GNUPLOT 4.1                                                      152


                      }
                      { model { RGB | HSV | CMY | YIQ | XYZ } }
                      { positive | negative }
                      { nops_allcF | ps_allcF }
                      { maxcolors <maxcolors> }
                    }
           show palette
           show palette palette <n> {{float | int}}
           show palette gradient
           show palette fit2rgbformulae
           show palette rgbformulae
           show palette colornames

     [1mset palette [22m(i.e. without options) sets up the default values.
     Otherwise, the options can be given in any order.  [1mshow palette[0m
     shows the current palette properties.

     [1mshow palette gradient [22mdisplays the gradient defining the
     palette (if appropriate).  [1mshow palette rgbformulae [22mprints the
     available fixed gray --> color transformation formulae.  [1mshow[0m
     [1mpalette colornames [22mprints the implemented color names.

     [1mshow palette palette <n> [22mprints to screen or to the file given
     by [1mset output [22mtable of RGB triplets calculated for the current
     palette settings and a palette having <n> discrete colors.  The
     default wide table can be limited to 3 columns of r,g,b float
     values [0..1] or integer values [0..255] by options float or
     int, respectively.  This way, the current gnuplot color palette
     can be loaded into other imaging applications, for example
     Octave.  Additionally to this textual list of RGB table, you
     can enjoy command [1mtest palette [22mto draw graphically the R,G,B
     profiles for the current palette.

     The following options determine the coloring properties.

     Figure using this palette can be [1mgray [22mor [1mcolor[22m.  For instance,
     in [1mpm3d [22mcolor surfaces the gray of each small spot is obtained
     by mapping the averaged z-coordinate of the 4 corners of sur-
     face quadrangles into the range [min_z,max_z] providing range
     of grays [0:1]. This value can be used directly as the gray for
     gray maps. The color map requires a transformation gray -->
     (R,G,B), i.e. a mapping [0:1] --> ([0:1],[0:1],[0:1]).

     Basically two different types of mappings can be used:  Ana-
     lytic formulae to convert gray to color, or discrete mapping
     tables which are interpolated.  [1mpalette rgbformulae [22mand [1mpalette[0m
     [1mfunctions [22muse analytic formulae whereas [1mpalette defined [22mand
     [1mpalette file [22muse interpolated tables.  [1mpalette rgbformulae[0m
     reduces the size of postscript output to a minimum.

     The command [1mshow palette fit2rgbformulae [22mfinds the best match-
     ing [1mset palette rgbformulae [22mfor the current [1mset palette[22m. Natu-
     rally, it makes sense to use it for non-rgbformulae palettes.










GNUPLOT 4.1                                                      153


     This command can be found useful mainly for external programs
     using the same rgbformulae definition of palettes as gnuplot,
     like zimg (
               http://zimg.sourceforge.net
      ).

     [1mset palette gray [22mswitches to a gray only palette. [1mset palette[0m
     [1mrgbformulae[22m, [1mset palette defined[22m, [1mset palette file [22mand [1mset[0m
     [1mpalette functions [22mswitch to a color mapping. [1mset palette color[0m
     is an easy way to switch back from the gray palette to the last
     color mapping.

     Automatic gamma correction via [1mset palette gamma <gamma> [22mcan be
     done for gray maps only ([1mset palette gray[22m).  Linear mapping to
     gray is for gamma equals 1, see [1mtest palette[22m.  Gamma is ignored
     for color mappings.

     Most terminals support only discrete number of colors (e.g. 256
     colors in gif).  All entries of the palette remaining after the
     default gnuplot linetype colors declaration are allocated for
     pm3d by default.  Then [1mmultiplot [22mcould fail if there are no
     more color positions in the terminal available.  Then you
     should use [1mset palette maxcolors <maxcolors> [22mwith a reasonably
     small value.  This option can also be used to separate levels
     of z=constant in discrete steps, thus to emulate filled con-
     tours. Default value of 0 stays for allocating all remaining
     entries in the terminal palette or for to use exact mapping to
     RGB.

     RGB color space might not be the most useful color space to
     work in.  For that reason you may change the color space with
     [1mmodel [22mto one of [1mRGB[22m, [1mHSV[22m, [1mCMY[22m, [1mYIQ [22mand [1mXYZ[22m.  Using color names
     for [1mset palette defined [22mtables and a color space other than RGB
     will result in funny colors.  All explanation have been written
     for RGB color space, so please note, that [1mR [22mcan be [1mH[22m, [1mC[22m, [1mY[22m, or
     [1mX[22m, depending on the actual color space ([1mG [22mand [1mB [22maccordingly).

     All values for all color spaces are limited to [0,1].

     RGB stands for Red, Green and Blue;  CMY stands for Cyan,
     Magenta and Yellow; HSV stands for Hue, Saturation, and Value;
     YIQ is the color model used by the U.S. Commercial Color Tele-
     vision Broadcasting, it is basically an RGB recoding with down-
     ward compatibility for black and white television; XYZ are the
     three primary colors of the color model defined by the 'Commis-
     sion Internationale de l'Eclairage' (CIE).  For more informa-
     tion on color models see:
               http://www.cs.rit.edu/~ncs/color/glossary.htm
     and
               http://cs.fit.edu/wds/classes/cse5255/cse5255/davis/index.html













GNUPLOT 4.1                                                      154


          [1m45.50.1.  Rgbformulae[0m


          For [1mrgbformulae [22mthree suitable mapping functions have to
          be chosen.  This is done via [1mrgbformulae <r>,<g>,<b>[22m.  The
          available mapping functions are listed by [1mshow palette[0m
          [1mrgbformulae[22m.  Default is [1m7,5,15[22m, some other examples are
          [1m3,11,6[22m, [1m21,23,3 [22mor [1m3,23,21[22m.  Negative numbers, like
          [1m3,-11,-6[22m, mean inverted color (i.e.  1-gray passed into
          the formula, see also [1mpositive [22mand [1mnegative [22moptions
          below).

          Some nice schemes in RGB color space
             7,5,15   ... traditional pm3d (black-blue-red-yellow)
             3,11,6   ... green-red-violet
             23,28,3  ... ocean (green-blue-white); try also all
          other permutations
             21,22,23 ... hot (black-red-yellow-white)
             30,31,32 ... color printable on gray (black-blue-vio-
          let-yellow-white)
             33,13,10 ... rainbow (blue-green-yellow-red)
             34,35,36 ... AFM hot (black-red-yellow-white)

          A full color palette in HSV color space
             3,2,2    ... red-yellow-green-cyan-blue-magenta-red

          Please note that even if called [1mrgbformulae [22mthe formulas
          might actually determine the <H>,<S>,<V> or <X>,<Y>,<Z> or
          ... color components as usual.

          Use [1mpositive [22mand [1mnegative [22mto invert the figure colors.

          Note that it is possible to find a set of the best match-
          ing rgbformulae for any other color scheme by the command
             show palette fit2rgbformulae



          [1m45.50.2.  Defined[0m


          Gray-to-rgb mapping can be manually set by use of [1mpalette[0m
          [1mdefined[22m:  A color gradient is defined and used to give the
          rgb values.  Such a  gradient is a piecewise linear map-
          ping from gray values in [0,1] to the RGB space
          [0,1]x[0,1]x[0,1].  You have to specify the gray values
          and the corresponding RGB values in between a linear
          interpolation shall take place:

          Syntax:
                set palette  defined { ( <gray1> <color1> {, <grayN>
          <colorN>}... ) }











GNUPLOT 4.1                                                      155


          <grayX> are gray values which are mapped to [0,1] and
          <colorX> are the corresponding rgb colors.  The color can
          be specified in three different ways:

               <color> :=  { <r> <g> <b> | '<color-name>' |
          '#rrggbb' }

          Either by three numbers (each in [0,1]) for red, green and
          blue, separated by whitespace, or the name of the color in
          quotes or X style color specifiers also in quotes.  You
          may freely mix the three types in a gradient definition,
          but the named color "red" will be something strange if RGB
          is not selected as color space.  Use [1mshow palette color-[0m
          [1mnames [22mfor a list of known color names.

          Please note, that even if written as <r>, this might actu-
          ally be the <H> component in HSV color space or <X> in
          CIE-XYZ space, or ...  depending on the selected color
          model.

          The <gray> values have to form an ascending sequence of
          real numbers; the sequence will be automatically rescaled
          to [0,1].

          [1mset palette defined [22m(without a gradient definition in
          braces) switches to RGB color space and uses a preset
          full-spectrum color gradient.  Use [1mshow palette gradient[0m
          to display the gradient.

          Examples:

          To produce a gray palette (useless but instructive) use:
                set palette model RGB
                set palette defined ( 0 "black", 1 "white" )

          To produce a blue yellow red palette use (all equivalent):
                set palette defined ( 0 "blue", 1 "yellow", 2 "red"
          )
                set palette defined ( 0 0 0 1, 1 1 1 0, 2 1 0 0 )
                set palette defined ( 0 "#0000ff", 1 "#ffff00", 2
          "#ff0000" )

          To produce some rainbow-like palette use:
                set palette defined ( 0 "blue", 3 "green", 6 "yel-
          low", 10 "red" )

          Full color spectrum within HSV color space:
                set palette model HSV
                set palette defined ( 0 0 1 1, 1 1 1 1 )
                set palette defined ( 0 0 1 0, 1 0 1 1, 6 0.8333 1
          1, 7 0.8333 0 1)

          To produce a palette with few colors only use:










GNUPLOT 4.1                                                      156


                set palette model RGB maxcolors 4
                set palette defined ( 0 "blue", 1 "green", 2 "yel-
          low", 3 "red" )

          'Traffic light' palette (non-smooth color jumps at gray =
          1/3 and 2/3).
                set palette model RGB
                set palette defined (0 "dark-green", 1 "green", 1
          "yellow", \
                                     2 "dark-yellow", 2 "red", 3
          "dark-red" )




          [1m45.50.3.  Functions[0m


          Use [1mset palette functions <Rexpr>, <Gexpr>, <Bexpr> [22mto
          define three formulae for the R(gray), G(gray) and B(gray)
          mapping.  The three formulae may depend on the variable
          [1mgray [22mwhich will take values in [0,1] and should also pro-
          duce values in [0,1].  Please note that <Rexpr> might be a
          formula for the H-value if HSV color space has been chosen
          (same for all other formulae and color spaces).

          Examples:

          To produce a full color palette use:
                set palette model HSV functions gray, 1, 1

          A nice black to gold palette:
                set palette model XYZ functions gray**0.35,
          gray**0.5, gray**0.8

          A gamma-corrected black and white palette
                gamma = 2.2
                color(gray) = gray**(1./gamma)
                set palette model RGB functions color(gray),
          color(gray), color(gray)




          [1m45.50.4.  File[0m


          [1mset palette file [22mis basically a [1mset palette defined (<gra-[0m
          [1mdient>) [22mwhere <gradient> is read from a datafile.  Either
          4 columns (gray,R,G,B) or just three columns (R,G,B) have
          to be selected via the [1musing [22mdata file modifier.  In the
          three column case, the line number will be used as gray.
          The gray range is automatically rescaled to [0,1].  The










GNUPLOT 4.1                                                      157


          file is read as a normal data file, so all datafile modi-
          fiers can be used.  Please note, that [1mR [22mmight actually be
          e.g. [1mH [22mif HSV color space is selected.

          As usual <filename> may be [1m'-' [22mwhich means that the data
          follow the command inline and are terminated by a single [1me[0m
          on a line of its own.

          Use [1mshow palette gradient [22mto display the gradient.

          Examples:

          Read in a palette of RGB triples each in range [0,255]:
                set palette file 'some-palette' using
          ($1/255):($2/255):($3/255)

          Equidistant rainbow (blue-green-yellow-red) palette:
                set palette model RGB file "-"
                0 0 1
                0 1 0
                1 1 0
                1 0 0
                e

          Binary palette files are supported as well, see [1mbinary[0m
          [1mgeneral[22m. Example: put 64 triplets of R,G,B doubles into
          file palette.bin and load it by
                set palette file "palette.bin" binary record=64
          using 1:2:3





          [1m45.50.5.  Gamma correction[0m


          For gray mappings gamma correction can be turned on by [1mset[0m
          [1mpalette gamma <gamma>[22m.  <gamma> defaults to 1.5 which is
          quite suitable for most terminals.

          For color mappings no automatic gamma correction is done
          by gnuplot.  However, you may easily implement gamma cor-
          rection.  Here is an example for a gray scale image by use
          of explicit functions for the red, green and blue compo-
          nent with slightly different values of gamma

          Example:
                set palette model RGB
                set palette functions gray**0.64, gray**0.67,
          gray**0.70

          To use gamma correction with interpolated gradients










GNUPLOT 4.1                                                      158


          specify intermediate gray values with appropriate colors.
          Instead of

                set palette defined ( 0 0 0 0, 1 1 1 1 )

          use e.g.

                set palette defined ( 0 0 0 0, 0.5 .73 .73 .73, 1 1
          1 1 )

          or even more intermediate points until the linear interpo-
          lation fits the "gamma corrected" interpolation well
          enough.




          [1m45.50.6.  Postscript[0m


          In order to reduce the size of postscript files, the gray
          value and not all three calculated r,g,b values are writ-
          ten to the file.  Therefore the analytical formulae are
          coded directly in the postscript language as a header just
          before the pm3d drawing, see /g and /cF definitions.  Usu-
          ally, it makes sense to write therein definitions of only
          the 3 formulae used.  But for multiplot or any other rea-
          son you may want to manually edit the transformations
          directly in the postscript file.  This is the default
          option [1mnops_allcF[22m.  Using the option [1mps_allcF [22mwrites
          postscript definitions of all formulae.  This you may find
          interesting if you want to edit the postscript file in
          order to have different palettes for different surfaces in
          one graph.  Well, you can achieve this functionality by
          [1mmultiplot [22mwith fixed [1morigin [22mand [1msize[22m.

          If pm3d map has been plotted from gridded or almost regu-
          lar data with an output to a postscript file, then it is
          possible to reduce the size of this postscript file up to
          at about 50% by the enclosed awk script [1mpm3dCompress.awk[22m.
          This you may find  interesting if you intend to keep the
          file for including it into your publication or before
          downloading a very large file into a slow printer. Usage:
              awk -f pm3dCompress.awk thefile.ps >smallerfile.ps

          If pm3d map has been plotted from rectangular gridded data
          with an output to a postscript file, then it is possible
          to reduce the file size even more by the enclosed awk
          script [1mpm3dConvertToImage.awk[22m.  Usage:
              awk -f pm3dConvertToImage.awk <thefile.ps >smaller-
          file.ps

          You may manually change the postscript output from gray to










GNUPLOT 4.1                                                      159


          color and vice versa and change the definition of <maxcol-
          ors>.



          [1m45.50.7.  Colornames[0m


          Gnuplot knows a limited number of color names. You can use
          these to define the color range spanned by a pm3d palette,
          or to assign a terminal-independent colot to a particular
          linetype or linestyle. To see the list of know color
          names, use the command [1mshow palette colornames[22m.  See [1mset[0m
          [1mpalette[22m, [1mlinestyle[22m.



     [1m45.51.  Pointsize[0m


     The [1mset pointsize [22mcommand scales the size of the points used in
     plots.

     Syntax:
           set pointsize <multiplier>
           show pointsize

     The default is a multiplier of 1.0.  Larger pointsizes may be
     useful to make points more visible in bitmapped graphics.

     The pointsize of a single plot may be changed on the [1mplot [22mcom-
     mand.  See [1mplot with [22mfor details.

     Please note that the pointsize setting is not supported by all
     terminal types.



     [1m45.52.  Polar[0m


     The [1mset polar [22mcommand changes the meaning of the plot from
     rectangular coordinates to polar coordinates.

     Syntax:
           set polar
           unset polar
           show polar

     There have been changes made to polar mode in version 3.7, so
     that scripts for [1mgnuplot [22mversions 3.5 and earlier will require
     modification.  The main change is that the dummy variable t is
     used for the angle so that the x and y ranges can be controlled










GNUPLOT 4.1                                                      160


     independently.  Other changes are: 1) tics are no longer put
     along the zero axes automatically ---use [1mset xtics axis nomir-[0m
     [1mror[22m; [1mset ytics axis nomirror[22m; 2) the grid, if selected, is not
     automatically polar ---use [1mset grid polar[22m; 3) the grid is not
     labelled with angles ---use [1mset label [22mas necessary.

     In polar coordinates, the dummy variable (t) is an angle.  The
     default range of t is [0:2*pi], or, if degree units have been
     selected, to [0:360] (see [1mset angles[22m).

     The command [1munset polar [22mchanges the meaning of the plot back to
     the default rectangular coordinate system.

     The [1mset polar [22mcommand is not supported for [1msplot[22ms.  See the [1mset[0m
     [1mmapping [22mcommand for similar functionality for [1msplot[22ms.

     While in polar coordinates the meaning of an expression in t is
     really r = f(t), where t is an angle of rotation.  The trange
     controls the domain (the angle) of the function, and the x and
     y ranges control the range of the graph in the x and y direc-
     tions.  Each of these ranges, as well as the rrange, may be
     autoscaled or set explicitly.  See [1mset xrange [22mfor details of
     all the [1mranges [22mcommands.

     Example:
           set polar
           plot t*sin(t)
           plot [-2*pi:2*pi] [-3:3] [-3:3] t*sin(t)

     The first [1mplot [22muses the default polar angular domain of 0 to
     2*pi.  The radius and the size of the graph are scaled automat-
     ically.  The second [1mplot [22mexpands the domain, and restricts the
     size of the graph to [-3:3] in both directions.

     You may want to [1mset size square [22mto have [1mgnuplot [22mtry to make the
     aspect ratio equal to unity, so that circles look circular.
     See also polar demos (polar.dem) and polar data plot (pol-
     dat.dem).



     [1m45.53.  Print[0m


     The [1mset print [22mcommand redirects the output of the [1mprint [22mcommand
     to a file.

     Syntax:
           set print
           set print "-"
           set print "<filename>"
           set print "<filename>" append
           set print "|<shell_command>"










GNUPLOT 4.1                                                      161


     Without "<filename>", the output file is restored to <STDERR>.
     The <filename> "-" means <STDOUT>. The [1mappend [22mflag causes the
     file to be opened in append mode.  A <filename> starting with
     "|" is opened as a pipe to the <shell_command> on platforms
     that support piping.



     [1m45.54.  Object[0m


     This command defines a single object, which will appear in all
     subsequent 2D plots. You may define as many objects as you
     like. Currently the only object type supported is [1mrectangle[22m.
     Each rectangle is specified by a pair of points that define
     diagonal vertices.  A default set of style properties (fill,
     color, border) are inherited from those set by the command [1mset[0m
     [1mstyle rectangle[22m, but each rectangle can also be given individ-
     ual style properties.

     Syntax:
         set object <index> rectangle
             {from <position> {to|rto} <position> |
              center <position> size <w>,<h> |
              at <position> size <w>,<h>}
             {front|back|behind} {fc|fillcolor <colorspec>} {fs
     <fillstyle>}
             {default} {lw|linewidth <width>}

     The position of the rectangle may be specified by giving the
     position of two diagonal corners (bottom left and top right) or
     by giving the position of the center followed by the width and
     the height.  In either case the positions may be given in axis,
     graph, or screen coordinates. See [1mcoordinates[22m.  The options [1mat[0m
     and [1mcenter [22mare synonyms.

     Setting [1mfront [22mwill draw the rectangle in front of all plot ele-
     ments, but behind any labels that are also marked [1mfront[22m. Set-
     ting [1mback [22mwill place the rectangle behind all plot curves and
     labels. Setting [1mbehind [22mwill place the rectangle behind every-
     thing including the axes and [1mback [22mrectangles, and can be used
     to provide a colored background for the entire graph or page.

     The fill color of the rectangle is taken from the <colorspec>.
     [1mfillcolor [22mmay be abbreviated [1mfc[22m.  The fill style is taken from
     <fillstyle>.  See [1mcolorspec [22mand [1mfillstyle[22m.  If the keyword
     [1mdefault [22mis given, these properties are inherited from the
     default settings of at the time a plot is drawn. See [1mset style[0m
     [1mrectangle[22m.

     Examples:
         # Force the entire area enclosed by the axes to have back-
     ground color cyan










GNUPLOT 4.1                                                      162


         set object 1 rect from graph 0, graph 0 to graph 1, graph 1
     back
         set object 1 rect fc rgb "cyan" fillstyle solid 1.0

         # Position a red square with lower left at 0,0 and upper
     right at 2,3
         set object 2 rect from 0,0 to 2,3 fc lt 1

         # Position an empty rectangle (no fill) with a blue border
         set object 3 rect from 0,0 to 2,3 fs empty border 3

         # Return fill and color to the default style but leave ver-
     tices unchanged
         set object 2 rect default




     [1m45.55.  Rmargin[0m


     The command [1mset rmargin [22msets the size of the right margin.
     Please see [1mset margin [22mfor details.



     [1m45.56.  Rrange[0m


     The [1mset rrange [22mcommand sets the range of the radial coordinate
     for a graph in polar mode.  Please see [1mset xrange [22mfor details.



     [1m45.57.  Samples[0m


     The sampling rate of functions, or for interpolating data, may
     be changed by the [1mset samples [22mcommand.

     Syntax:
           set samples <samples_1> {,<samples_2>}
           show samples

     By default, sampling is set to 100 points.  A higher sampling
     rate will produce more accurate plots, but will take longer.
     This parameter has no effect on data file plotting unless one
     of the interpolation/approximation options is used.  See [1mplot[0m
     [1msmooth [22mre 2-d data and [1mset cntrparam [22mand [1mset dgrid3d [22mre 3-d
     data.

     When a 2-d graph is being done, only the value of <samples_1>
     is relevant.










GNUPLOT 4.1                                                      163


     When a surface plot is being done without the removal of hidden
     lines, the value of samples specifies the number of samples
     that are to be evaluated for the isolines.  Each iso-v line
     will have <sample_1> samples and each iso-u line will have
     <sample_2> samples.  If you only specify <samples_1>, <sam-
     ples_2> will be set to the same value as <samples_1>.  See also
     [1mset isosamples[22m.



     [1m45.58.  Size[0m


     Syntax:
           set size {{no}square | ratio <r> | noratio}
     {<xscale>,<yscale>}
           show size

     The <xscale> and <yscale> values are scale factors for the size
     of the plot, which includes the graph, labels, and margins.

     Important note:
           In earlier versions of gnuplot, some terminal types used
     the values from
           `set size` to control also the size of the output canvas;
     others did not.
           In version 4.2 most terminals now follow the convention
     described below.
           However, see `backwards compatibility` for the
     png/gif/jpeg drivers.

     [1mset term <terminal_type> size <XX>, <YY> [22mcontrols the size of
     the output file, or [1mcanvas[22m. Please see individual terminal doc-
     umentation for allowed values of the size parameters.  By
     default, the plot will fill this canvas.

     [1mset size <XX>, <YY> [22mscales the plot itself relative to the size
     of the canvas.  Scale values less than 1 will cause the plot to
     not fill the entire canvas.  Scale values larger than 1 will
     cause only a portion of the plot to fit on the canvas.  Please
     be aware that setting scale values larger than 1 may cause
     problems on some terminal types.  See [1mset term size[22m.

     [1mratio [22mcauses [1mgnuplot [22mto try to create a graph with an aspect
     ratio of <r> (the ratio of the y-axis length to the x-axis
     length) within the portion of the plot specified by <xscale>
     and <yscale>.

     The meaning of a negative value for <r> is different.  If
     <r>=-1, gnuplot tries to set the scales so that the unit has
     the same length on both the x and y axes (suitable for geo-
     graphical data, for instance).  If <r>=-2, the unit on y has
     twice the length of the unit on x, and so on.










GNUPLOT 4.1                                                      164


     The success of [1mgnuplot [22min producing the requested aspect ratio
     depends on the terminal selected.  The graph area will be the
     largest rectangle of aspect ratio <r> that will fit into the
     specified portion of the output (leaving adequate margins, of
     course).

     [1msquare [22mis a synonym for [1mratio 1[22m.

     Both [1mnoratio [22mand [1mnosquare [22mreturn the graph to the default
     aspect ratio of the terminal, but do not return <xscale> or
     <yscale> to their default values (1.0).

     [1mratio [22mand [1msquare [22mhave no effect on 3-d plots.

     Examples:

     To set the size so that the plot fills the available canvas:
           set size 1,1

     To make the graph half size and square use:
           set size square 0.5,0.5

     To make the graph twice as high as wide use:
           set size ratio 2

     See also
      airfoil demo.



     [1m45.59.  Style[0m


     Default plotting styles are chosen with the [1mset style data [22mand
     [1mset style function [22mcommands.  See [1mplot with [22mfor information
     about how to override the default plotting style for individual
     functions and data sets.  See [1mplotting styles [22mfor a complete
     list of styles.

     Syntax:
           set style function <style>
           set style data <style>
           show style function
           show style data

     Default styles for specific plotting elements may also be set.

     Syntax:
           set style arrow <n> <arrowstyle>
           set style fill <fillstyle>
           set style histogram <histogram style options>
           set style line <n> <linestyle>











GNUPLOT 4.1                                                      165


          [1m45.59.1.  Set style arrow[0m


          Each terminal has a default set of arrow and point types,
          which can be seen by using the command [1mtest[22m.  [1mset style[0m
          [1marrow [22mdefines a set of arrow types and widths and point
          types and sizes so that you can refer to them later by an
          index instead of repeating all the information at each
          invocation.

          Syntax:
                set style arrow <index> default
                set style arrow <index> {nohead | head | heads}
                                        {size
          <length>,<angle>{,<backangle>}}
                                        {filled | empty | nofilled}
                                        {front | back}
                                        { {linestyle | ls
          <line_style>}
                                          | {linetype | lt
          <line_type>}
                                            {linewidth | lw
          <line_width} }
                unset style arrow
                show style arrow

          <index> is an integer that identifies the arrowstyle.

          If [1mdefault [22mis given all arrow style parameters are set to
          their default values.

          If the linestyle <index> already exists, only the given
          parameters are changed while all others are preserved.  If
          not, all undefined values are set to the default values.

          Specifying [1mnohead [22mproduces arrows drawn without a head---a
          line segment.  This gives you yet another way to draw a
          line segment on the plot.  By default, arrows have one
          head. Specifying [1mheads [22mdraws arrow heads on both ends of
          the line.

          Head size can be controlled by [1msize <length>,<angle> [22mor
          [1msize <length>,<angle>,<backangle>[22m, where [1m<length> [22mdefines
          length of each branch of the arrow head and [1m<angle> [22mthe
          angle (in degrees) they make with the arrow.  [1m<Length> [22mis
          in x-axis units; this can be changed by [1mfirst[22m, [1msecond[22m,
          [1mgraph[22m, [1mscreen[22m, or [1mcharacter [22mbefore the <length>;  see
          [1mcoordinates [22mfor details.  [1m<Backangle> [22monly takes effect
          when [1mfilled [22mor [1mempty [22mis also used.  Then, [1m<backangle> [22mis
          the angle (in degrees) the back branches make with the
          arrow (in the same direction as [1m<angle>[22m).  The [1mfig [22mtermi-
          nal has a restricted backangle function. It supports three
          different angles. There are two thresholds: Below 70










GNUPLOT 4.1                                                      166


          degrees, the arrow head gets an indented back angle. Above
          110 degrees, the arrow head has an acute back angle.
          Between these thresholds, the back line is straight.

          Specifying [1mfilled [22mproduces filled arrow heads (if heads
          are used).  Filling is supported on filled-polygon capable
          terminals, see help of [1mpm3d [22mfor their list, otherwise the
          arrow heads are closed but not filled.  The same result
          (closed but not filled arrow head) is reached by specify-
          ing [1mempty[22m.  Further, filling and outline is obviously not
          supported on terminals drawing arrows by their own spe-
          cific routines, like [1mmetafont[22m, [1mmetapost[22m, [1mlatex [22mor [1mtgif[22m.

          The line style may be selected from a user-defined list of
          line styles (see [1mset style line[22m) or may be defined here by
          providing values for [1m<line_type> [22m(an index from the
          default list of styles) and/or [1m<line_width> [22m(which is a
          multiplier for the default width).

          Note, however, that if a user-defined line style has been
          selected, its properties (type and width) cannot be
          altered merely by issuing another [1mset style arrow [22mcommand
          with the appropriate index and [1mlt [22mor [1mlw[22m.

          If [1mfront [22mis given, the arrows are written on top of the
          graphed data. If [1mback [22mis given (the default), the arrow is
          written underneath the graphed data.  Using [1mfront [22mwill
          prevent a arrow from being obscured by dense data.

          Examples:

          To draw an arrow without an arrow head and double width,
          use:
                set style arrow 1 nohead lw 2
                set arrow arrowstyle 1

           See also `set arrow` for further examples.




          [1m45.59.2.  Set style data[0m


          The [1mset style data [22mcommand changes the default plotting
          style for data plots.

          Syntax:
                set style data <plotting-style>
                show style data

          See [1mplotting styles [22mfor the choices.  If no choice is
          given, the choices are listed.  [1mshow style data [22mshows the










GNUPLOT 4.1                                                      167


          current default data plotting style.



          [1m45.59.3.  Set style fill[0m


          The [1mset style fill [22mcommand is used to set the style of
          boxes, histograms, candlesticks and filledcurves.

          Syntax:
                set style fill {empty | solid {<density>} | pattern
          {<n>}}
                               {border {<linetype>} | noborder}

          The default fillstyle is [1mempty[22m.

          The [1msolid [22moption causes filling with a solid color, if the
          terminal supports that. The <density> parameter specifies
          the intensity of the fill color. At a <density> of 0.0,
          the box is empty, at <density> of 1.0, the inner area is
          of the same color as the current linetype.  Some terminal
          types can vary the density continuously; others implement
          only a few levels of partial fill.  If no <density> param-
          eter is given, it defaults to 1.

          The [1mpattern [22moption causes filling to be done with a fill
          pattern supplied by the terminal driver.  The kind and
          number of available fill patterns depend on the terminal
          driver.  If multiple datasets using filled boxes are plot-
          ted, the pattern cycles through all available pattern
          types, starting from pattern <n>, much as the line type
          cycles for multiple line plots.

          The [1mempty [22moption causes filled boxes not to be filled.
          This is the default.  It is equivalent to the [1msolid [22moption
          with a <density> parameter of zero.

          By default, [1mborder[22m, the box is bounded by a solid line of
          the current linetype. [1mborder <lt> [22mspecifies that a border
          is to be drawn using linetype <lt>. [1mnoborder [22mspecifies
          that no bounding lines are drawn.



          [1m45.59.4.  Set style function[0m


          The [1mset style function [22mcommand changes the default plot-
          ting style for function plots.

          Syntax:
                set style function <plotting-style>










GNUPLOT 4.1                                                      168


                show style function

          See [1mplotting styles [22mfor the choices.  If no choice is
          given, the choices are listed.  [1mshow style function [22mshows
          the current default function plotting style.



          [1m45.59.5.  Set style increment[0m


          Syntax:
                set style increment {default|userstyles}
                show style increment

          By default, successive plots within the same graph will
          use successive linetypes from the default set for the cur-
          rent terminal type.  However, choosing [1mset style increment[0m
          [1muser [22mallows you to step through the user-defined line
          styles rather than through the default linetypes.

          Example:

                set style line 1 lw 2 lc rgb "gold"
                set style line 2 lw 2 lc rgb "purple"
                set style line 4 lw 1 lc rgb "sea-green"
                set style increment user

                plot f1(x), f2(x), f3(x), f4(x)

          should plot functions f1, f2, f4 in your 3 newly defined
          line styles.  If a user-defined line style is not found
          then the corresponding default linetype is used instead.
          E.g. in the example above, f3(x) will be plotted using the
          default linetype 3.




          [1m45.59.6.  Set style line[0m


          Each terminal has a default set of line and point types,
          which can be seen by using the command [1mtest[22m.  [1mset style[0m
          [1mline [22mdefines a set of line types and widths and point
          types and sizes so that you can refer to them later by an
          index instead of repeating all the information at each
          invocation.

          Syntax:
                set style line <index> default
                set style line <index> {{linetype  | lt} <line_type>
          | <colorspec>}










GNUPLOT 4.1                                                      169


                                       {{linecolor | lc} <color-
          spec>}
                                       {{linewidth | lw}
          <line_width>}
                                       {{pointtype | pt}
          <point_type>}
                                       {{pointsize | ps}
          <point_size>}
                                       {palette}
                unset style line
                show style line

          If [1mdefault [22mis given all line style parameters are set to
          their default values.

          If the linestyle <index> already exists, only the given
          parameters are changed while all others are preserved.  If
          not, all undefined values are set to the default values.

          The line and point types are taken from the default types
          for the terminal currently in use.  The line width and
          point size are multipliers for the default width and size
          (but note that <point_size> here is unaffected by the mul-
          tiplier given on [1mset pointsize[22m).

          The defaults for the line and point types is the index.
          The defaults for the width and size are both unity.

          Linestyles created by this mechanism do not replace the
          default linetype styles; both may be used.  If you want
          plots to use the defined styles in preference to the
          default linetypes, please see [1mset style increment[22m.

          Not all terminals support the [1mlinewidth [22mand [1mpointsize [22mfea-
          tures; if not supported, the option will be ignored.

          Terminal-independent colors may be assigned using either
          [1mlinecolor <colorspec> [22mor [1mlinetype <colorspec>[22m, abbreviated
          [1mlc [22mor [1mlt[22m.  This requires giving a RGB color triple, a
          known palette color name, a fractional index into the cur-
          rent palette, or a constant value from the current mapping
          of the palette onto cbrange.  See [1mcolors[22m, [1mcolorspec[22m, [1mset[0m
          [1mpalette[22m, [1mcolornames[22m, [1mcbrange[22m.

          [1mset style line <n> linetype <lt> [22mwill set both a terminal-
          dependent dot/dash pattern and color. The commands[1mset[0m
          [1mstyle line <n> linecolor <colorspec> [22mor [1mset style line <n>[0m
          [1mlinetype <colorspec> [22mwill set a new line color while leav-
          ing the existing dot-dash pattern unchanged.

          In 3d mode ([1msplot [22mcommand), the special keyword [1mpalette [22mis
          allowed as a shorthand for "linetype palette z".  The
          color value corresponds to the z-value (elevation) of the










GNUPLOT 4.1                                                      170


          splot, and varies smoothly along a line or surface.

          Examples: Suppose that the default lines for indices 1, 2,
          and 3 are red, green, and blue, respectively, and the
          default point shapes for the same indices are a square, a
          cross, and a triangle, respectively.  Then

                set style line 1 lt 2 lw 2 pt 3 ps 0.5

          defines a new linestyle that is green and twice the
          default width and a new pointstyle that is a half-sized
          triangle.  The commands

                set style function lines
                plot f(x) lt 3, g(x) ls 1

          will create a plot of f(x) using the default blue line and
          a plot of g(x) using the user-defined wide green line.
          Similarly the commands

                set style function linespoints
                plot p(x) lt 1 pt 3, q(x) ls 1

          will create a plot of p(x) using the default triangles
          connected by a red line and q(x) using small triangles
          connected by a green line.

                splot sin(sqrt(x*x+y*y))/sqrt(x*x+y*y) w l pal

          creates a surface plot using smooth colors according to
          [1mpalette[22m. Note, that this works only on some terminals. See
          also [1mset palette[22m, [1mset pm3d[22m.

                set style line 10 linetype 1 linecolor rgb "cyan"

          will assign linestyle 10 to be a solid cyan line on any
          terminal that supports rgb colors.




          [1m45.59.7.  Plotting styles[0m



          The commands [1mset style data [22mand [1mset style function [22mchange
          the default plotting style for subsequent [1mplot [22mand [1msplot[0m
          commands.

          The types used for all line and point styles (i.e., solid,
          dash-dot, color, etc. for lines; circles, squares,
          crosses, etc. for points) will be either those specified
          on the [1mplot [22mor [1msplot [22mcommand or will be chosen










GNUPLOT 4.1                                                      171


          sequentially from the types available to the terminal in
          use.  Use the command [1mtest [22mto see what is available.

          None of the styles requiring more than two columns of
          information (e.g., [1merrorbars [22mor [1merrorlines[22m) can be used
          with [1msplot[22ms or function [1mplot[22ms. Neither [1mboxes[22m, [1mfilledcurves[0m
          nor any of the [1msteps [22mstyles can be used with [1msplot[22ms. If an
          inappropriate style is specified, it will be changed to
          [1mpoints[22m.

          The above caveat does not apply to [1mplot with labels[22m, for
          which the third column specifies a data source rather than
          coordinate information.  See [1mset style labels[22m.

          For 2-d data with more than two columns, [1mgnuplot [22mis picky
          about the allowed [1merrorbars [22mand [1merrorlines [22mstyles. The
          [1musing [22moption on the [1mplot [22mcommand can be used to set up the
          correct columns for the style you want. (In this discus-
          sion, "column" will be used to refer both to a column in
          the data file and an entry in the [1musing [22mlist.)

          For three columns, only [1mxerrorbars[22m, [1myerrorbars [22m(or [1merror-[0m
          [1mbars[22m), [1mxerrorlines[22m, [1myerrorlines [22m(or [1merrorlines[22m), [1mboxes[22m,
          and [1mboxerrorbars [22mare allowed. If another plot style is
          used, the style will be changed to [1myerrorbars[22m. The [1mboxer-[0m
          [1mrorbars [22mstyle will calculate the boxwidth automatically.

          For four columns, only [1mxerrorbars[22m, [1myerrorbars [22m(or [1merror-[0m
          [1mbars[22m), [1mxyerrorbars[22m, [1mxerrorlines[22m, [1myerrorlines [22m(or [1merror-[0m
          [1mlines[22m), [1mxyerrorlines[22m, [1mboxxyerrorbars[22m, and [1mboxerrorbars [22mare
          allowed.  An illegal style will be changed to [1myerrorbars[22m.

          Five-column data allow only the [1mboxerrorbars[22m, [1mfinancebars[22m,
          and [1mcandlesticks [22mstyles.  An illegal style will be changed
          to [1mboxerrorbars [22mbefore plotting.

          Six- and seven-column data only allow the [1mxyerrorbars[22m,
          [1mxyerrorlines[22m, and [1mboxxyerrorbars [22mstyles. Illegal styles
          will be changed to [1mxyerrorbars [22mbefore plotting.

          For more information about error bars with and without
          lines, please see [1mplot errorlines [22mand [1mplot errorbars[22m.




          [1m45.59.8.  Set style rectangle[0m



          Rectangles defined with the [1mset object rectangle [22mcommand
          can have individual styles. However, if a rectangle is not
          assigned a private style then it inherits a default that










GNUPLOT 4.1                                                      172


          is taken from the [1mset style rectangle [22mcommand.

          Syntax:
              set style rectangle {front|back} {fillcolor <color-
          spec>} {fs <fillstyle>}
                                  {lw|linewidth <lw>}

          See [1mcolorspec [22mand [1mfillstyle[22m.  [1mfillcolor [22mmay be abbreviated
          as [1mfc[22m.

          Examples:
              set style rectangle back fc rgb "white" fs solid 1.0
          border -1
              set style rectangle fc linsestyle 3 fs pattern 2
          noborder

          The default values correspond to solid fill with the back-
          ground color and a black border.





               [1m45.59.8.1.  Boxerrorbars[0m


               The [1mboxerrorbars [22mstyle is only relevant to 2-d data
               plotting.  It is a combination of the [1mboxes [22mand [1myer-[0m
               [1mrorbars [22mstyles.  The boxwidth will come from the
               fourth column if the y errors are in the form of
               "ydelta" and the boxwidth was not previously set
               equal to -2.0 ([1mset boxwidth -2.0[22m) or from the fifth
               column if the y errors are in the form of "ylow
               yhigh".  The special case  [1mboxwidth = -2.0 [22mis for
               four-column data with y errors in the form "ylow
               yhigh".  In this case the boxwidth will be calculated
               so that each box touches the adjacent boxes.  The
               width will also be calculated in cases where three-
               column data are used.

               The box height is determined from the y error in the
               same way as it is for the [1myerrorbars [22mstyle---either
               from y-ydelta to y+ydelta or from ylow to yhigh,
               depending on how many data columns are provided.  See
               also errorbar demo.



               [1m45.59.8.2.  Boxes[0m


               The [1mboxes [22mstyle is only relevant to 2-d plotting.  It
               draws a box centered about the given x coordinate










GNUPLOT 4.1                                                      173


               from the x axis (not the graph border) to the given y
               coordinate.  The width of the box is obtained in one
               of three ways.  If it is a data plot and the data
               file has a third column, this will be used to set the
               width of the box.  If not, if a width has been set
               using the [1mset boxwidth [22mcommand, this will be used.
               If neither of these is available, the width of each
               box will be calculated automatically so that it
               touches the adjacent boxes.

               The interior of the boxes is drawn according to the
               current fillstyle.  See [1mset style fill [22mfor details.
               Alternatively a new fillstyle may be specified in the
               plot command.

               For fillstyle [1mempty [22mthe box is filled with the back-
               ground color.

               For fillstyle [1msolid [22mthe box is filled with a solid
               rectangle of the current drawing color. There is an
               optional parameter <density> that controls the fill
               density; it runs from 0 (background color) to 1 (cur-
               rent drawing color).

               For fillstyle [1mpattern [22mthe box is filled in the cur-
               rent drawing color with a pattern, if supported by
               the terminal driver.

               Examples:

               To plot a data file with solid filled boxes with a
               small vertical space separating them (bargraph):

                     set boxwidth 0.9 relative
                     set style fill solid 1.0
                     plot 'file.dat' with boxes

               To plot a sine and a cosine curve in pattern-filled
               boxes style:

                     set style fill pattern
                     plot sin(x) with boxes, cos(x) with boxes

               The sin plot will use pattern 0; the cos plot will
               use pattern 1.  Any additional plots would cycle
               through the patterns supported by the terminal
               driver.

               To specify explicit fillstyles for each dataset:

                    plot 'file1' with boxes fs solid 0.25, \
                         'file2' with boxes fs solid 0.50, \
                         'file3' with boxes fs solid 0.75, \










GNUPLOT 4.1                                                      174


                         'file4' with boxes fill pattern 1, \
                         'file5' with boxes fill empty

               Currently only the following terminal drivers support
               fillstyles other than [1mempty[22m: x11, windows, pm, wxt,
               postscript, fig, pbm, png, gif, hpdj, hppj, hpljii,
               hp500c, jpeg, nec_cp6, epson_180dpi, epson_60dpi,
               epson_lx800, okidata, starc and tandy_60dpi. The BeOS
               driver ([1mbe[22m) is untested.



               [1m45.59.8.3.  Boxxyerrorbars[0m


               The [1mboxxyerrorbars [22mstyle is only relevant to 2-d data
               plotting.  It is a combination of the [1mboxes [22mand [1mxyer-[0m
               [1mrorbars [22mstyles.

               The box width and height are determined from the x
               and y errors in the same way as they are for the
               [1mxyerrorbars [22mstyle---either from xlow to xhigh and
               from ylow to yhigh, or from x-xdelta to x+xdelta and
               from y-ydelta to y+ydelta , depending on how many
               data columns are provided.

               If filled-box support is present, then the interior
               of the boxes is drawn according to the current fill-
               style.  See [1mset style fill [22mand [1mboxes [22mfor details.
               Alternatively a new fillstyle may be specified in the
               plot command.



               [1m45.59.8.4.  Candlesticks[0m


               The [1mcandlesticks [22mstyle can be used for 2-d data plot-
               ting of financial data or for generating box-and-
               whisker plots of statistical data.  Five columns of
               data are required; in order, these should be the x
               coordinate (most likely a date) and the opening, low,
               high, and closing prices.  The symbol is a rectangu-
               lar box, centered horizontally at the x coordinate
               and limited vertically by the opening and closing
               prices.  A vertical line segment at the x coordinate
               extends up from the top of the rectangle to the high
               price and another down to the low.  The vertical line
               will be unchanged if the low and high prices are
               interchanged.

               The width of the rectangle can be controlled by the
               [1mset boxwidth [22mcommand.  For backwards compatibility










GNUPLOT 4.1                                                      175


               with earlier gnuplot versions, when the boxwidth
               parameter has not been set then the width of the can-
               dlestick rectangle is controlled by [1mset bars <width>[22m.

               By default the vertical line segments have no cross-
               bars at the top and bottom. If you want crossbars,
               which are typically used for box-and-whisker plots,
               then add the keyword [1mwhiskerbars [22mto the plot command.
               By default these whiskerbars extend the full horizon-
               tal width of the candlestick, but you can modify this
               by specifying a fraction of the full width.

               By default the rectangle is empty if (open > close),
               and filled with three vertical bars if (close >
               open). If filled-boxes support is present, then the
               rectangle is colored according to [1mset style fill[0m
               [1m<fillstyle>[22m.  See [1mset bars [22mand [1mfinancebars[22m.  See also
               finance demos .

               Note: To place additional symbols, such as the median
               value, on a box-and-whisker plot requires additional
               plot commands as in this example:

                 # Data columns: X Min 1stQuartile Median 3rdQuar-
               tile Max
                 set bars 4.0
                 set style fill empty
                 plot 'stat.dat' using 1:3:2:6:5 with candlesticks
               title 'Quartiles', \
                      ''         using 1:4:4:4:4 with candlesticks
               lt -1 notitle

                 # Plot with crossbars on the whiskers, crossbars
               are 50% of full width
                 plot 'stat.dat' using 1:3:2:6:5 with candlesticks
               whiskerbars 0.5

                See `set boxwidth`, `set bars` and `set style fill`.



               [1m45.59.8.5.  Dots[0m


               The [1mdots [22mstyle plots a tiny dot at each point; this
               is useful for scatter plots with many points. For
               some terminals (post, pdf) the size of the dot can be
               controlled by changing the linewidth.















GNUPLOT 4.1                                                      176


               [1m45.59.8.6.  Filledcurves[0m


               The [1mfilledcurves [22mstyle is only relevant to 2-d plot-
               ting. Three variants are possible. The first two
               variants require either a function or two columns of
               input data, and may be further modified by the
               options listed below.  The first variant, [1mclosed[22m,
               treats the curve itself as a closed polygon.  This is
               the default.

               The second variant is to fill the area between the
               curve and a given axis, a horizontal or vertical
               line, or a point.

               The third variant requires three columns of input
               data: the x coordinate and two y coordinates corre-
               sponding to two curves sampled at the same set of x
               coordinates; the area between the two curves is
               filled.

               Syntax:

                   set style [data | function] filledcurves [option]
                   plot ... with filledcurves [option]

               where the option can be

                   [closed | {above | below} {x1 | x2 | y1 |
               y2}[=<a>] | xy=<x>,<y>]

               The first two plot variants can be further modified
               by the options

                   filledcurves closed   ... just filled closed
               curve,
                   filledcurves x1       ... x1 axis,
                   filledcurves x2       ... x2 axis, etc for y1 and
               y2 axes,
                   filledcurves y1=0     ... line y=0 (at y1 axis)
               ie parallel to x1 axis,
                   filledcurves y2=42    ... line y=42 (at y2 axis)
               ie parallel to x2, etc,
                   filledcurves xy=10,20 ... point 10,20 of x1,y1
               axes (arc-like shape).

               Example of filling the area between two input curves.
               fill between curves demo.

                   plot 'data' using 1:2:3 with filledcurves

               The [1mabove [22mand [1mbelow [22moptions apply both to commands of
               the form










GNUPLOT 4.1                                                      177


                   ... filledcurves above {x1|x2|y1|y2}=<val>
               and to commands of the form
                   ... using 1:2:3 with filledcurves below
               In either case the option limits the filled area to
               one side of the bounding line or curve.

               Note: Not all terminal types support this plotting
               mode.

               Zoom of a filled curve drawn from a datafile may pro-
               duce empty or incorrect area because gnuplot is clip-
               ping points and lines, and not areas.

               If the values of <a>, <x>, <y> are out of the drawing
               boundary, then they are moved to the graph boundary.
               Then the actually filled area in the case of option
               xy=<x>,<y> will depend on xrange and yrange.



               [1m45.59.8.7.  Financebars[0m


               The [1mfinancebars [22mstyle is only relevant for 2-d data
               plotting of financial data.  Five columns of data are
               required; in order, these should be the x coordinate
               (most likely a date) and the opening, low, high, and
               closing prices.  The symbol is a vertical line seg-
               ment, located horizontally at the x coordinate and
               limited vertically by the high and low prices.  A
               horizontal tic on the left marks the opening price
               and one on the right marks the closing price.  The
               length of these tics may be changed by [1mset bars[22m.  The
               symbol will be unchanged if the high and low prices
               are interchanged.  See [1mset bars [22mand [1mcandlesticks[22m, and
               also the finance demo.



               [1m45.59.8.8.  Fsteps[0m


               The [1mfsteps [22mstyle is only relevant to 2-d plotting.
               It connects consecutive points with two line seg-
               ments: the first from (x1,y1) to (x1,y2) and the sec-
               ond from (x1,y2) to (x2,y2).  See also steps demo.



               [1m45.59.8.9.  Histeps[0m













GNUPLOT 4.1                                                      178


               The [1mhisteps [22mstyle is only relevant to 2-d plotting.
               It is intended for plotting histograms.  Y-values are
               assumed to be centered at the x-values; the point at
               x1 is represented as a horizontal line from
               ((x0+x1)/2,y1) to ((x1+x2)/2,y1).  The lines repre-
               senting the end points are extended so that the step
               is centered on at x.  Adjacent points are connected
               by a vertical line at their average x, that is, from
               ((x1+x2)/2,y1) to ((x1+x2)/2,y2).

               If [1mautoscale [22mis in effect, it selects the xrange from
               the data rather than the steps, so the end points
               will appear only half as wide as the others.  See
               also steps demo.

               [1mhisteps [22mis only a plotting style; [1mgnuplot [22mdoes not
               have the ability to create bins and determine their
               population from some data set.



               [1m45.59.8.10.  Histograms[0m


               The [1mhistograms [22mstyle is only relevant to 2-d plot-
               ting.  It produces a bar chart from a sequence of
               data columns in parallel. Each element of the [1mplot[0m
               command must specify a single input data source (e.g.
               one column of the input file), possibly with associ-
               ated tic values or key titles.  Four styles of his-
               togram layout are currently supported.

                     set style histogram clustered {gap <gapsize>}
                     set style histogram errorbars {gap <gapsize>}
               {<linewidth>}
                     set style histogram rowstacked
                     set style histogram columnstacked

               The default style corresponds to [1mset style histogram[0m
               [1mclustered gap 2[22m.  In this style, each set of parallel
               data values is collected into a group of boxes clus-
               tered at the x-axis coordinate corresponding to their
               sequential position (row #) in the selected datafile
               columns.  Thus if <n> datacolumns are selected, the
               first cluster is centered about x=1, and contains <n>
               boxes whose heights are taken from the first entry in
               the corresponding <n> data columns.  This is followed
               by a gap and then a second cluster of boxes centered
               about x=2 corresponding to the second entry in the
               respective data columns, and so on.  The default gap
               width of 2 indicates that the empty space between
               clusters is equivalent to the width of 2 boxes.  All
               boxes derived from any one column are given the same










GNUPLOT 4.1                                                      179


               fill color and/or pattern (see [1mset style fill[22m).

               Each cluster of boxes is derived from a single row of
               the input data file.  It is common in such input
               files that the first element of each row is a label.
               Labels from this column may be placed along the x-
               axis underneath the appropriate cluster of boxes with
               the [1mxticlabels [22moption to [1musing[22m.

               The [1merrorbars [22mstyle is very similar to the [1mclustered[0m
               style, except that it requires two columns of input
               for each entry. The first column is treated as the
               height (y-value) of that box, exactly as for the
               [1mclustered [22mstyle.  The second column is treated as an
               error magnitude, and used to generate a vertical
               error bar at the top of the box. The appearance of
               the error bar is controlled by the current value of
               [1mset bars [22mand by the optional <linewidth> specifica-
               tion.

               Two styles of stacked histogram are supported, chosen
               by the command [1mset style histogram {row-[0m
               [1mstacked|columnstacked}[22m.  In these styles the data
               values from the selected columns are collected into
               stacks of boxes.  The default stacking mode is [1mrow-[0m
               [1mstacked[22m.

               The [1mrowstacked [22mstyle places a box resting on the x-
               axis for each data value in the first selected col-
               umn; the first data value results in a box a x=1, the
               second at x=2, and so on.  Boxes corresponding to the
               second and subsequent data columns are layered on top
               of these, resulting in a stack of boxes at x=1 repre-
               senting the first data value from each column, a
               stack of boxes at x=2 representing the second data
               value from each column, and so on.  All boxes derived
               from any one column are given the same fill color
               and/or pattern (see [1mset style fill[22m).

               The [1mcolumnstacked [22mstyle is similar, except that each
               stack of boxes is built up from a single data column.
               Each data value from the first specified column
               yields a box in the stack at x=1, each data value
               from the second specified column yields a box in the
               stack at x=2, and so on.  In this style the color of
               each box is taken from the row number, rather than
               the column number, of the corresponding data field.

               Box widths may be modified using the [1mset boxwidth[0m
               command.  Box fill styles may be set using the [1mset[0m
               [1mstyle fill [22mcommand.

               Histograms always use the x1 axis, but may use either










GNUPLOT 4.1                                                      180


               y1 or y2.  If a plot contains both histograms and
               other plot styles, the non-histogram plot elements
               may use either the x1 or the x2 axis.

               Examples:

               To plot a data file containing multiple columns of
               data as a histogram of clustered boxes (the default
               style):

                     set boxwidth 0.9 relative
                     set style data histograms
                     set style fill solid 1.0 border -1
                     plot 'file.dat' using 2, '' using 4, '' using 6

               This will produce a plot with clusters of three boxes
               (vertical bars) centered at each integral value on
               the x axis.  If the first column of the input file
               contains labels, they may be placed along the x-axis
               using the variant command

                     plot 'file.dat' using 2, '' using 4, '' using
               6:xticlabels(1)

               If the file contains both a magnitude and an error
               estimate for each value, then error bars can be added
               to the plot.  The following commands will add error
               bars extending from (y-<error>) to (y+<error>),
               capped by horizontal bar ends drawn the same width as
               the box itself. The error bars and bar ends are drawn
               in black with linewidth 2.

                     set bars fullwidth
                     set style histogram errorbars gap 2 lt -1 lw 2
                     plot 'file.dat' using 2:3, '' using 4:5, ''
               using 6:7:xticlabels(1)

               To plot the same data as a rowstacked histogram:

                     set style histogram rows
                     plot 'file.dat' using 2, '' using 4, '' using
               6:xtic(1)

               This will produce a plot in which each vertical bar
               contains a stack of three segments, corresponding in
               height to the values found in columns 2, 4 and 6 of
               the datafile.

               Finally, the commands

                     set style histogram columnstacked
                     plot 'file.dat' using 2, '' using 4, '' using 6











GNUPLOT 4.1                                                      181


               will produce three vertical stacks. The stack at x=1
               will contain a box for each entry in column 2 of the
               datafile.  The stack at x=2 will contain a box for
               each parallel entry in column 4 of the datafile, and
               the stack at x=3 a box for each entry of column 6.
               Because this interchanges gnuplot's usual interpreta-
               tion of input rows and columns, the specification of
               key titles and x-axis tic labels must also be modi-
               fied.

                     set style histogram columnstacked
                     plot '' u 5:key(1)            # uses first col-
               umn to generate key titles
                     plot '' u 5 title columnhead  # uses first row
               to generate xtic labels




                    [1m45.59.8.10.1.  Newhistogram[0m


                    More than one set of histograms can appear in a
                    single plot. In this case you can force a gap
                    between them, and a separate label for each set,
                    by using the plot command [1mnewhistogram { "title"[0m
                    [1m} { <linestyle> }[22m.  For example

                          set style histogram  cluster
                          plot newhistogram "Set A", 'a' using 1, ''
                    using 2, '' using 3, \
                               newhistogram "Set B", 'b' using 1, ''
                    using 2, '' using 3

                    The labels "Set A" and "Set B" will appear
                    beneath the respective sets of histograms, under
                    the overall x axis label.

                    The newhistogram command can also be used to
                    force histogram coloring to begin with a spe-
                    cific color (linetype). By default colors will
                    continue to increment successively even across
                    histogram boundaries. Here is an example using
                    the same coloring for multiple histograms
                          plot newhistogram "Set A" lt 4, 'a' using
                    1, '' using 2, '' using 3, \
                               newhistogram "Set B" lt 4, 'b' using
                    1, '' using 2, '' using 3















GNUPLOT 4.1                                                      182


               [1m45.59.8.11.  Image[0m


               The [1mimage [22mstyle is intendend for plotting 2D images.
               It may be used for both [1mplot [22mand [1msplot [22min the form of
               3D data (x,y,value) or projected 4D data
               (x,y,z,value), respectively.  It is assumed that in
               the viewing plane the image data forms an equidistant
               sampling grid in the viewing plane along two, not
               necessarily  orthogonal, directions.  In other words,
               groups of four adjacent points are assumed to form
               the same size parallelogram.  The variable [1mvalue [22min
               the tuples represent a palette color (gray value) for
               indexing in the current palette.

               The [1mimage [22mstyle will attempt to create a properly
               positioned and scaled data matrix to match the plot
               borders for those terminals supporting palettes and
               images.  Such output is efficient and draws quickly.
               However, when a terminal driver does not support
               palettes and images, or when image support is not
               implemented, the [1mimage [22mstyle reverts to drawing
               filled rectangular boxes for pixels, which is not as
               efficient.  General parallelogram-shaped images cur-
               rently always have filled parallelograms for pixels.

               The coordinate of each data point of an image will
               lie at the center of a pixel.  That is, an M x N set
               of data will form an image with M x N pixels.  This
               is slightly different than pm3d elements where an M x
               N set of data will form a surface of (M-1) x (N-1)
               elements.  The scan directions for the image data
               grid can be any of eight possible combinations.

               Here are some specific comments about particular ter-
               minal drivers:

               x11 and wxt - Pixels are either repeated or decimated
               to fit the display
                     resolution; no other processing (filtering) is
               done.  Thus, aliasing may
                     occur when decimating images having high spa-
               tial frequency content.

               postscript (pslatex, epslatex, pstex) - Image is
               copied in its original
                     resolution, and sample interpolation is turned
               off.

               png - Output is dependent on the installed version of
               libgd.
                     gd 1.8.4  No truecolor support, but the driver
               function works.










GNUPLOT 4.1                                                      183


                     gd 2.0.4  Truecolor works, but if truecolor is
               not selected
                               the image comes out blank.
                     gd 2.0.9  Truecolor works, non-truecolor also
               works.

               See also [1mrgbimage[22m.



               [1m45.59.8.12.  Impulses[0m


               The [1mimpulses [22mstyle displays a vertical line from the
               x axis (not the graph border), or from the grid base
               for [1msplot[22m, to each point.



               [1m45.59.8.13.  Labels[0m


               The [1mlabels [22mstyle is available only if gnuplot is
               built with configuration option --enable-datastrings.
               For a 2-D plot with labels you must specify 3 input
               data columns; the text string found in the third col-
               umn is printed at the X and Y coordinates generated
               by the first two column specifiers. The font, color,
               rotation angle and other properties of the printed
               text may be specified as additional command options
               (see [1mset label[22m). The example below will generate a
               2-D plot with text labels taken from column 4 of the
               input file ([1mtc lt 2 [22mis shorthand for [1mtextcolor line-[0m
               [1mtype 2[22m, which is green).

                 plot 'datafile' using 1:(0.5 * $2):4 with labels
               font "arial,11" tc lt 2

               The [1mlabels [22mstyle can also be used in 3-D plots. In
               this case four input column specifiers are required,
               corresponding to X Y Z and text.

                 splot 'datafile' using 1:2:3:4 with labels

               See also [1mdatastrings[22m, [1mset style data[22m.



               [1m45.59.8.14.  Lines[0m


               The [1mlines [22mstyle connects adjacent points with
               straight line segments.  See also [1mlinetype[22m,










GNUPLOT 4.1                                                      184


               [1mlinewidth[22m, and [1mlinestyle[22m.



               [1m45.59.8.15.  Linespoints[0m


               The [1mlinespoints [22mstyle does both [1mlines [22mand [1mpoints[22m,
               that is, it draws a small symbol at each point and
               then connects adjacent points with straight line seg-
               ments.  The command [1mset pointsize [22mmay be used to
               change the size of the points.  See [1mset pointsize [22mfor
               its usage.

               [1mlinespoints [22mmay be abbreviated [1mlp[22m.



               [1m45.59.8.16.  Points[0m


               The [1mpoints [22mstyle displays a small symbol at each
               point.  The command [1mset pointsize [22mmay be used to
               change the size of the points.  See [1mset pointsize [22mfor
               its usage.



               [1m45.59.8.17.  Steps[0m


               The [1msteps [22mstyle is only relevant to 2-d plotting.  It
               connects consecutive points with two line segments:
               the first from (x1,y1) to (x2,y1) and the second from
               (x2,y1) to (x2,y2).  See also steps demo.



               [1m45.59.8.18.  Rgbimage[0m


               The [1mrgbimage [22mstyle is intended for plotting 2D images
               and is similar in concept to [1mimage[22m.  See [1mimage [22mfor
               details.  The difference is that 5D data (x,y,r,g,b)
               for [1mplot [22mand 6D data (x,y,z,r,g,b) for [1msplot [22mdescribe
               the coordinates and color components of an image.
               Currently, color images are only possible when the
               sampling grid is rectangular and oriented with the
               view plane.  General orientations must be done with
               filled polygons which only support palette table
               lookup, not primary colors.

               See also [1mimage[22m.










GNUPLOT 4.1                                                      185


               [1m45.59.8.19.  Vectors[0m


               The 2D [1mvectors [22mstyle draws a vector from (x,y) to
               (x+xdelta,y+ydelta).  Thus it requires four columns
               of data.  It also draws a small arrowhead at the end
               of the vector.  The 3D [1mvectors [22mstyle is similar, but
               requires six columns of data.  splot with vectors is
               supported only for [1mset mapping cartesian[22m.  The key-
               words "with vectors" may be followed by arrow style
               specifications.  See [1marrowstyle [22mfor more details.

               Example:
                     plot 'file.dat' using 1:2:3:4 with vectors head
               filled lt 2
                     splot 'file.dat' using 1:2:3:(1):(1):(1) with
               vectors filled head lw 2

               [1mset clip one [22mand [1mset clip two [22maffect vectors drawn in
               2D.  Please see [1mset clip [22mand [1marrowstyle[22m.



               [1m45.59.8.20.  Xerrorbars[0m


               The [1mxerrorbars [22mstyle is only relevant to 2-d data
               plots.  [1mxerrorbars [22mis like [1mdots[22m, except that a hori-
               zontal error bar is also drawn.  At each point (x,y),
               a line is drawn from (xlow,y) to (xhigh,y) or from
               (x-xdelta,y) to (x+xdelta,y), depending on how many
               data columns are provided.  A tic mark is placed at
               the ends of the error bar (unless [1mset bars [22mis
               used---see [1mset bars [22mfor details).



               [1m45.59.8.21.  Xyerrorbars[0m


               The [1mxyerrorbars [22mstyle is only relevant to 2-d data
               plots.  [1mxyerrorbars [22mis like [1mdots[22m, except that hori-
               zontal and vertical error bars are also drawn.  At
               each point (x,y), lines are drawn from (x,y-ydelta)
               to (x,y+ydelta) and from (x-xdelta,y) to (x+xdelta,y)
               or from (x,ylow) to (x,yhigh) and from (xlow,y) to
               (xhigh,y), depending upon the number of data columns
               provided.  A tic mark is placed at the ends of the
               error bar (unless [1mset bars [22mis used---see [1mset bars [22mfor
               details).

               If data are provided in an unsupported mixed form,
               the [1musing [22mfilter on the [1mplot [22mcommand should be used










GNUPLOT 4.1                                                      186


               to set up the appropriate form.  For example, if the
               data are of the form (x,y,xdelta,ylow,yhigh), then
               you can use

                     plot 'data' using 1:2:($1-$3):($1+$3):4:5 with
               xyerrorbars



               [1m45.59.8.22.  Yerrorbars[0m


               The [1myerrorbars [22m(or [1merrorbars[22m) style is only relevant
               to 2-d data plots.  [1myerrorbars [22mis like [1mpoints[22m, except
               that a vertical error bar is also drawn.  At each
               point (x,y), a line is drawn from (x,y-ydelta) to
               (x,y+ydelta) or from (x,ylow) to (x,yhigh), depending
               on how many data columns are provided.  A tic mark is
               placed at the ends of the error bar (unless [1mset bars[0m
               is used---see [1mset bars [22mfor details).  See also error-
               bar demo.



               [1m45.59.8.23.  Xerrorlines[0m


               The [1mxerrorlines [22mstyle is only relevant to 2-d data
               plots.  [1mxerrorlines [22mis like [1mlinespoints[22m, except that
               a horizontal error line is also drawn. At each point
               (x,y), a line is drawn from (xlow,y) to (xhigh,y) or
               from (x-xdelta,y) to (x+xdelta,y), depending on how
               many data columns are provided. A tic mark is placed
               at the ends of the error bar (unless [1mset bars [22mis
               used---see [1mset bars [22mfor details).



               [1m45.59.8.24.  Xyerrorlines[0m


               The [1mxyerrorlines [22mstyle is only relevant to 2-d data
               plots.  [1mxyerrorlines [22mis like [1mlinespoints[22m, except that
               horizontal and vertical error bars are also drawn. At
               each point (x,y), lines are drawn from (x,y-ydelta)
               to (x,y+ydelta) and from (x-xdelta,y) to (x+xdelta,y)
               or from (x,ylow) to (x,yhigh) and from (xlow,y) to
               (xhigh,y), depending upon the number of data columns
               provided. A tic mark is placed at the ends of the
               error bar (unless [1mset bars [22mis used---see [1mset bars [22mfor
               details).

               If data are provided in an unsupported mixed form,










GNUPLOT 4.1                                                      187


               the [1musing [22mfilter on the [1mplot [22mcommand should be used
               to set up the appropriate form.  For example, if the
               data are of the form (x,y,xdelta,ylow,yhigh), then
               you can use

                     plot 'data' using 1:2:($1-$3):($1+$3):4:5 with
               xyerrorlines



               [1m45.59.8.25.  Yerrorlines[0m


               The [1myerrorlines [22m(or [1merrorlines[22m) style is only rele-
               vant to 2-d data plots. [1myerrorlines [22mis like [1mlines-[0m
               [1mpoints[22m, except that a vertical error line is also
               drawn. At each point (x,y), a line is drawn from
               (x,y-ydelta) to (x,y+ydelta) or from (x,ylow) to
               (x,yhigh), depending on how many data columns are
               provided. A tic mark is placed at the ends of the
               error bar (unless [1mset bars [22mis used---see [1mset bars [22mfor
               details).  See also errorbar demo.



     [1m45.60.  Surface[0m


     The command [1mset surface [22mcontrols the display of surfaces by
     [1msplot[22m.

     Syntax:
           set surface
           unset surface
           show surface

     The surface is drawn with the style specified by [1mwith[22m, or else
     the appropriate style, data or function.

     Whenever [1munset surface [22mis issued, [1msplot [22mwill not draw points or
     lines corresponding to the function or data file points.  Con-
     tours may still be drawn on the surface, depending on the [1mset[0m
     [1mcontour [22moption. [1munset surface; set contour base [22mis useful for
     displaying contours on the grid base.  See also [1mset contour[22m.



     [1m45.61.  Table[0m


     When [1mtable [22mmode is enabled, [1mplot [22mand [1msplot [22mcommands print out a
     multicolumn ASCII table of X Y {Z} R values rather than creat-
     ing an actual plot on the current terminal.  The character R










GNUPLOT 4.1                                                      188


     takes on one of three values: "i" if the point is in the active
     range, "o" if it is out-of-range, or "u" if it is undefined.
     The data format is determined by the format of the axis labels
     (see [1mset format[22m), and the columns are separated by single
     spaces.  This can be useful if you want to generate contours
     and then save them for further use, perhaps for plotting with
     [1mplot[22m;  see [1mset contour [22mfor example.  The same method can be
     used to save interpolated data (see [1mset samples [22mand [1mset[0m
     [1mdgrid3d[22m).

     Syntax:
           set table {"outfile"}
           plot <whatever>
           unset table

     Tabular output is written to the named file, if any, otherwise
     it is written to the current value of [1mset output[22m.  You must
     explicitly [1munset table [22min order to go back to normal plotting
     on the current terminal.



     [1m45.62.  Terminal[0m


     [1mgnuplot [22msupports many different graphics devices.  Use [1mset ter-[0m
     [1mminal [22mto tell [1mgnuplot [22mwhat kind of output to generate. Use [1mset[0m
     [1moutput [22mto redirect that output to a file or device.

     Syntax:
           set terminal {<terminal-type> | push | pop}
           show terminal

     If <terminal-type> is omitted, [1mgnuplot [22mwill list the available
     terminal types.  <terminal-type> may be abbreviated.

     If both [1mset terminal [22mand [1mset output [22mare used together, it is
     safest to give [1mset terminal [22mfirst, because some terminals set a
     flag which is needed in some operating systems.

     Several terminals have many additional options.  For example,
     see [1mpng[22m, or [1mpostscript[22m.  The options used by a previous invoca-
     tion [1mset term <term> <options> [22mof a given [1m<term> [22mare remem-
     bered, thus subsequent [1mset term <term> [22mdoes not reset them.
     This helps in printing, for instance, when switching among dif-
     ferent terminals---previous options don't have to be repeated.

     The command [1mset term push [22mremembers the current terminal
     including its settings while [1mset term pop [22mrestores it. This is
     equivalent to [1msave term [22mand [1mload term[22m, but without accessing
     the filesystem. Therefore they can be used to achieve platform
     independent restoring of the terminal after printing, for
     instance. After gnuplot's startup, the default terminal or that










GNUPLOT 4.1                                                      189


     from [1mstartup [22mfile is pushed automatically. Therefore portable
     scripts can rely that [1mset term pop [22mrestores the default termi-
     nal on a given platform unless another terminal has been pushed
     explicitly.

     For a complete list of available terminal types, see [1mterminal[22m.



     [1m45.63.  Termoption[0m


     The [1mset termoption [22mcommand allows you to change the behaviour
     of the current terminal without requiring a new [1mset terminal[0m
     command. Only one option can be changed per command, and only a
     small number of options can be changed this way. Currently the
     only options accepted are

          set termoption {no}enhanced
          set termoption font "<fontname>{,<fontsize>}"




     [1m45.64.  Tics[0m


     Control of the major (labelled) tics on all axes at once is
     possible with the [1mset tics [22mcommand.

     Fine control of the major (labelled) tics on all axes at once
     is possible with the [1mset tics [22mcommand.  The tics may be turned
     off with the [1munset tics [22mcommand, and may be turned on (the
     default state) with [1mset tics[22m.  Similar commands (by preceding
     'tics' by the axis name) control the major tics on a single
     axis.

     Syntax:
           set tics {axis | border} {{no}mirror}
                    {in | out} {scale {default | <major>
     {,<minor>}}}
                    {{no}rotate {by <ang>}} {offset <offset> |
     nooffset}
                    { font "name{,<size>}" }
                    { textcolor <colorspec> }
           unset tics
           show tics

     All specified options apply to all axes, i.e., x, y, z, x2, y2,
     and cb.

     [1maxis [22mor [1mborder [22mtells [1mgnuplot [22mto put the tics (both the tics
     themselves and the accompanying labels) along the axis or the










GNUPLOT 4.1                                                      190


     border, respectively.  If the axis is very close to the border,
     the [1maxis [22moption will move the tic labels to outside the border
     in case the border is printed (see [1mset border[22m).  The relevant
     margin settings will usually be sized badly by the automatic
     layout algorithm in this case.

     [1mmirror [22mtells [1mgnuplot [22mto put unlabelled tics at the same posi-
     tions on the opposite border.  [1mnomirror [22mdoes what you think it
     does.

     [1min [22mand [1mout [22mchange the tic marks to be drawn inwards or out-
     wards.

     With [1mscale[22m, the size of the tic marks can be adjusted. If
     <minor> is not specified, it is 0.5*<major>.  The default size
     1.0 for major tics and 0.5 for minor tics is requested by [1mscale[0m
     [1mdefault[22m.

     [1mrotate [22masks [1mgnuplot [22mto rotate the text through 90 degrees,
     which will be done if the terminal driver in use supports text
     rotation.  [1mnorotate [22mcancels this. [1mrotate by <ang> [22masks for
     rotation by <ang> degrees, supported by some terminal types.

     The defaults are [1mborder mirror norotate [22mfor tics on the x and y
     axes, and [1mborder nomirror norotate [22mfor tics on the x2 and y2
     axes.  For the z axis, the default is [1mnomirror[22m.

     The <offset> is specified by either x,y or x,y,z, and may be
     preceded by [1mfirst[22m, [1msecond[22m, [1mgraph[22m, [1mscreen[22m, or [1mcharacter [22mto
     select the coordinate system. <offset> is the offset of the
     tics texts from their default positions, while the default
     coordinate system is [1mcharacter[22m.  See [1mcoordinates [22mfor details.
     [1mnooffset [22mswitches off the offset.

     [1mset tics [22mwith no options restores to place tics inwards. Every
     other options are retained.

     See also [1mset xtics [22mfor more control of major (labelled) tic
     marks and [1mset mxtics [22mfor control of minor tic marks.  These
     commands provide control at a axis by axis basis.



     [1m45.65.  Ticslevel[0m


     See [1mset xyplane[22m.
















GNUPLOT 4.1                                                      191


     [1m45.66.  Ticscale[0m


     The [1mset ticscale [22mcommand is deprecated, use [1mset tics scale[0m
     instead.



     [1m45.67.  Timestamp[0m


     The command [1mset timestamp [22mplaces the time and date of the plot
     in the left margin.

     Syntax:
           set timestamp {"<format>"} {top|bottom} {{no}rotate}
                         {offset {<xoff>}{,<yoff>}} {font
     "<fontspec>"}
           unset timestamp
           show timestamp

     The format string allows you to choose the format used to write
     the date and time.  Its default value is what asctime() uses:
     "%a %b %d %H:%M:%S %Y" (weekday, month name, day of the month,
     hours, minutes, seconds, four-digit year).  With [1mtop [22mor [1mbottom[0m
     you can place the timestamp at the top or bottom of the left
     margin (default: bottom).  [1mrotate [22mlets you write the timestamp
     vertically, if your terminal supports vertical text.  The con-
     stants <xoff> and <yoff> are offsets that let you adjust the
     position more finely.  <font> is used to specify the font with
     which the time is to be written.

     The abbreviation [1mtime [22mmay be used in place of [1mtimestamp[22m.

     Example:
           set timestamp "%d/%m/%y %H:%M" offset 80,-2 font "Hel-
     vetica"

     See [1mset timefmt [22mfor more information about time format strings.



     [1m45.68.  Timefmt[0m


     This command applies to timeseries where data are composed of
     dates/times.  It has no meaning unless the command [1mset xdata[0m
     [1mtime [22mis given also.

     Syntax:
           set timefmt "<format string>"
           show timefmt











GNUPLOT 4.1                                                      192


     The string argument tells [1mgnuplot [22mhow to read timedata from the
     datafile.  The valid formats are:




  +---------------------------------------------------------------+
  |Format   Explanation                                           |
  +---------------------------------------------------------------+
  |  %d     day of the month, 1--31                               |
  |  %m     month of the year, 1--12                              |
  |  %y     year, 0--99                                           |
  |  %Y     year, 4-digit                                         |
  |  %j     day of the year, 1--365                               |
  |  %H     hour, 0--24                                           |
  |  %M     minute, 0--60                                         |
  |  %s     seconds since the Unix epoch (1970-01-01 00:00 UTC)   |
  |  %S     second, 0--60                                         |
  |  %b     three-character abbreviation of the name of the month |
  |  %B     name of the month                                     |
  +---------------------------------------------------------------+
  +---------------------------------------------------------------+


Any character is allowed in the string, but must match exactly.  \t
(tab) is recognized.  Backslash-octals (\nnn) are converted to char.
If there is no separating character between the time/date elements,
then %d, %m, %y, %H, %M and %S read two digits each, %Y reads four
digits and %j reads three digits.  %b requires three characters, and
%B requires as many as it needs.

Spaces are treated slightly differently.  A space in the string
stands for zero or more whitespace characters in the file.  That is,
"%H %M" can be used to read "1220" and "12     20" as well as "12
20".

Each set of non-blank characters in the timedata counts as one col-
umn in the [1musing n:n [22mspecification.  Thus [1m11:11  25/12/76  21.0 [22mcon-
sists of three columns.  To avoid confusion, [1mgnuplot [22mrequires that
you provide a complete [1musing [22mspecification if your file contains
timedata.

Since [1mgnuplot [22mcannot read non-numerical text, if the date format
includes the day or month in words, the format string must exclude
this text.  But it can still be printed with the "%a", "%A", "%b",
or "%B" specifier: see [1mset format [22mfor more details about these and
other options for printing timedata.  ([1mgnuplot [22mwill determine the
proper month and weekday from the numerical values.)

See also [1mset xdata [22mand [1mTime/date [22mfor more information.

Example:
      set timefmt "%d/%m/%Y\t%H:%M"










GNUPLOT 4.1                                                      193


tells [1mgnuplot [22mto read date and time separated by tab.  (But look
closely at your data---what began as a tab may have been converted
to spaces somewhere along the line; the format string must match
what is actually in the file.)  See also time data demo.



     [1m45.69.  Title[0m


     The [1mset title [22mcommand produces a plot title that is centered at
     the top of the plot.  [1mset title [22mis a special case of [1mset label[22m.

     Syntax:
           set title {"<title-text>"} {offset <offset>} {font
     "<font>{,<size>}"}
                     {{textcolor | tc} {lt <line_type> | default}}
     {{no}enhanced}
           show title

     If <offset> is specified by either x,y or x,y,z the title is
     moved by the given offset.  It may be preceded by [1mfirst[22m, [1msec-[0m
     [1mond[22m, [1mgraph[22m, [1mscreen[22m, or [1mcharacter [22mto select the coordinate sys-
     tem.  See [1mcoordinates [22mfor details.  By default, the [1mcharacter[0m
     coordinate system is used.  For example, "[1mset title offset[0m
     [1m0,-1[22m" will change only the y offset of the title, moving the
     title down by roughly the height of one character.  The size of
     a character depends on both the font and the terminal.

     <font> is used to specify the font with which the title is to
     be written; the units of the font <size> depend upon which ter-
     minal is used.

     [1mtextcolor lt <n> [22msets the text color to that of line type <n>.

     [1mnoenhanced [22mrequests that the title not be processed by the
     enhanced text mode parser, even if enhanced text mode is cur-
     rently active.

     [1mset title [22mwith no parameters clears the title.

     See [1msyntax [22mfor details about the processing of backslash
     sequences and the distinction between single- and double-
     quotes.



     [1m45.70.  Tmargin[0m


     The command [1mset tmargin [22msets the size of the top margin.
     Please see [1mset margin [22mfor details.











GNUPLOT 4.1                                                      194


     [1m45.71.  Trange[0m


     The [1mset trange [22mcommand sets the parametric range used to com-
     pute x and y values when in parametric or polar modes.  Please
     see [1mset xrange [22mfor details.



     [1m45.72.  Urange[0m


     The [1mset urange [22mand [1mset vrange [22mcommands set the parametric
     ranges used to compute x, y, and z values when in [1msplot [22mpara-
     metric mode.  Please see [1mset xrange [22mfor details.



     [1m45.73.  Variables[0m


     The [1mshow variables [22mcommand lists all user-defined variables and
     their values.

     Syntax:
           show variables {all}

     With the optional keyword "all", also the [1mgnuplot-defined vari-[0m
     [1mables [22mthat begin with [1mGPVAL_ [22mare listed.




     [1m45.74.  Version[0m


     The [1mshow version [22mcommand lists the version of gnuplot being
     run, its last modification date, the copyright holders, and
     email addresses for the FAQ, the gnuplot-info mailing list, and
     reporting bugs--in short, the information listed on the screen
     when the program is invoked interactively.

     Syntax:
           show version {long}

     When the [1mlong [22moption is given, it also lists the operating sys-
     tem, the compilation options used when [1mgnuplot [22mwas installed,
     the location of the help file, and (again) the useful email
     addresses.














GNUPLOT 4.1                                                      195


     [1m45.75.  View[0m


     The [1mset view [22mcommand sets the viewing angle for [1msplot[22ms.  It
     controls how the 3-d coordinates of the plot are mapped into
     the 2-d screen space.  It provides controls for both rotation
     and scaling of the plotted data, but supports orthographic pro-
     jections only.  It supports both 3D projection or orthogonal 2D
     projection into a 2D plot-like map.

     Syntax:
           set view { <rot_x>{,{<rot_z>}{,{<scale>}{,<scale_z>}}} |
     map }
           show view

     where <rot_x> and <rot_z> control the rotation angles (in
     degrees) in a virtual 3-d coordinate system aligned with the
     screen such that initially (that is, before the rotations are
     performed) the screen horizontal axis is x, screen vertical
     axis is y, and the axis perpendicular to the screen is z.  The
     first rotation applied is <rot_x> around the x axis.  The sec-
     ond rotation applied is <rot_z> around the new z axis.

     Command [1mset view map [22mis used to represent the drawing as a map.
     It can be used for [1mcontour [22mplots, or for color [1mpm3d [22mmaps. In
     the latter, take care that you properly use [1mzrange [22mand [1mcbrange[0m
     for input data point filtering and color range scaling, respec-
     tively.

     <rot_x> is bounded to the [0:180] range with a default of 60
     degrees, while <rot_z> is bounded to the [0:360] range with a
     default of 30 degrees.  <scale> controls the scaling of the
     entire [1msplot[22m, while <scale_z> scales the z axis only.  Both
     scales default to 1.0.

     Examples:
           set view 60, 30, 1, 1
           set view ,,0.5

     The first sets all the four default values.  The second changes
     only scale, to 0.5.

     See also [1mset ticslevel[22m.



     [1m45.76.  Vrange[0m


     The [1mset urange [22mand [1mset vrange [22mcommands set the parametric
     ranges used to compute x, y, and z values when in [1msplot [22mpara-
     metric mode.  Please see [1mset xrange [22mfor details.











GNUPLOT 4.1                                                      196


     [1m45.77.  X2data[0m


     The [1mset x2data [22mcommand sets data on the x2 (top) axis to time-
     series (dates/times).  Please see [1mset xdata[22m.



     [1m45.78.  X2dtics[0m


     The [1mset x2dtics [22mcommand changes tics on the x2 (top) axis to
     days of the week.  Please see [1mset xdtics [22mfor details.



     [1m45.79.  X2label[0m


     The [1mset x2label [22mcommand sets the label for the x2 (top) axis.
     Please see [1mset xlabel[22m.



     [1m45.80.  X2mtics[0m


     The [1mset x2mtics [22mcommand changes tics on the x2 (top) axis to
     months of the year.  Please see [1mset xmtics [22mfor details.



     [1m45.81.  X2range[0m


     The [1mset x2range [22mcommand sets the horizontal range that will be
     displayed on the x2 (top) axis.  Please see [1mset xrange [22mfor
     details.



     [1m45.82.  X2tics[0m


     The [1mset x2tics [22mcommand controls major (labelled) tics on the x2
     (top) axis.  Please see [1mset xtics [22mfor details.



     [1m45.83.  X2zeroaxis[0m













GNUPLOT 4.1                                                      197


     The [1mset x2zeroaxis [22mcommand draws a line at the origin of the x2
     (top) axis (y2 = 0).  For details, please see [1mset zeroaxis[22m.



     [1m45.84.  Xdata[0m


     This command sets the datatype on the x axis to time/date.  A
     similar command does the same thing for each of the other axes.

     Syntax:
           set xdata {time}
           show xdata

     The same syntax applies to [1mydata[22m, [1mzdata[22m, [1mx2data[22m, [1my2data [22mand
     [1mcbdata[22m.

     The [1mtime [22moption signals that the datatype is indeed time/date.
     If the option is not specified, the datatype reverts to normal.

     See [1mset timefmt [22mto tell gnuplot how to read date or time data.
     The time/date is converted to seconds from start of the cen-
     tury.  There is currently only one timefmt, which implies that
     all the time/date columns must conform to this format.  Speci-
     fication of ranges should be supplied as quoted strings accord-
     ing to this format to avoid interpretation of the time/date as
     an expression.

     The function 'strftime' (type "man strftime" on unix to look it
     up) is used to print tic-mark labels.  [1mgnuplot [22mtries to figure
     out a reasonable format for this  unless the [1mset format x[0m
     [1m"string" [22mhas supplied something that does not look like a deci-
     mal format (more than one '%' or neither %f nor %g).

     See also [1mTime/date [22mfor more information.



     [1m45.85.  Xdtics[0m


     The [1mset xdtics [22mcommands converts the x-axis tic marks to days
     of the week where 0=Sun and 6=Sat.  Overflows are converted
     modulo 7 to dates.  [1mset noxdtics [22mreturns the labels to their
     default values.  Similar commands do the same things for the
     other axes.

     Syntax:
           set xdtics
           unset xdtics
           show xdtics











GNUPLOT 4.1                                                      198


     The same syntax applies to [1mydtics[22m, [1mzdtics[22m, [1mx2dtics[22m, [1my2dtics [22mand
     [1mcbdtics[22m.

     See also the [1mset format [22mcommand.



     [1m45.86.  Xlabel[0m


     The [1mset xlabel [22mcommand sets the x axis label.  Similar commands
     set labels on the other axes.

     Syntax:
           set xlabel {"<label>"} {offset <offset>} {font
     "<font>{,<size>}"}
                      {{textcolor | tc} {lt <line_type> | default}}
     {{no}enhanced}
                      {rotate by <degrees>}
           show xlabel

     The same syntax applies to [1mx2label[22m, [1mylabel[22m, [1my2label[22m, [1mzlabel [22mand
     [1mcblabel[22m.

     If <offset> is specified by either x,y or x,y,z the label is
     moved by the given offset.  It may be preceded by [1mfirst[22m, [1msec-[0m
     [1mond[22m, [1mgraph[22m, [1mscreen[22m, or [1mcharacter [22mto select the coordinate sys-
     tem.  See [1mcoordinates [22mfor details.  By default, the [1mcharacter[0m
     coordinate system is used.  For example, "[1mset xlabel offset[0m
     [1m-1,0[22m" will change only the x offset of the title, moving the
     label roughly one character width to the left.  The size of a
     character depends on both the font and the terminal.

     <font> is used to specify the font in which the label is writ-
     ten; the units of the font <size> depend upon which terminal is
     used.

     [1mtextcolor lt <n> [22msets the text color to that of line type <n>.

     [1mnoenhanced [22mrequests that the label text not be processed by the
     enhanced text mode parser, even if enhanced text mode is cur-
     rently active.

     To clear a label, put no options on the command line, e.g.,
     "[1mset y2label[22m".

     The default positions of the axis labels are as follows:

     xlabel:  The x-axis label is centered below the bottom axis.

     ylabel:  The position of the y-axis label depends on the termi-
     nal, and can be one of the following three positions:











GNUPLOT 4.1                                                      199


     1. Horizontal text flushed left at the top left of the plot.
     Terminals that cannot rotate text will probably use this
     method.  If [1mset x2tics [22mis also in use, the ylabel may overwrite
     the left-most x2tic label.  This may be remedied by adjusting
     the ylabel position or the left margin.

     2. Vertical text centered vertically at the left of the plot.
     Terminals that can rotate text will probably use this method.

     3. Horizontal text centered vertically at the left of the plot.
     The EEPIC, LaTeX and TPIC drivers use this method.  The EEPIC
     driver will produce a stack of characters so as not to over-
     write the plot. With other drivers (such as LaTeX and TPIC),
     the user probably has to insert line breaks using \\ to prevent
     the ylabel from overwriting the plot.

     zlabel: The z-axis label is centered along the z axis and
     placed in the space above the grid level.

     cblabel: The color box axis label is centered along the box and
     placed below or right according to horizontal or vertical color
     box gradient.

     y2label: The y2-axis label is placed to the right of the y2
     axis.  The position is terminal-dependent in the same manner as
     is the y-axis label.

     x2label: The x2-axis label is placed above the top axis but
     below the plot title.  It is also possible to create an x2-axis
     label by using new-line characters to make a multi-line plot
     title, e.g.,

           set title "This is the title\n\nThis is the x2label"

     Note that double quotes must be used.  The same font will be
     used for both lines, of course.

     The y and y2 axis labels can be explicitly rotated from their
     default orientation, but this applies only to 2D plots and only
     on terminals that support text rotation.

     If you are not satisfied with the default position of an axis
     label, use [1mset label [22minstead--that command gives you much more
     control over where text is placed.

     Please see [1msyntax [22mfor further information about backslash pro-
     cessing and the difference between single- and double-quoted
     strings.















GNUPLOT 4.1                                                      200


     [1m45.87.  Xmtics[0m


     The [1mset xmtics [22mcommand converts the x-axis tic marks to months
     of the year where 1=Jan and 12=Dec.  Overflows are converted
     modulo 12 to months.  The tics are returned to their default
     labels by [1munset xmtics[22m.  Similar commands perform the same
     duties for the other axes.

     Syntax:
           set xmtics
           unset xmtics
           show xmtics

     The same syntax applies to [1mx2mtics[22m, [1mymtics[22m, [1my2mtics[22m, [1mzmtics [22mand
     [1mcbmtics[22m.

     See also the [1mset format [22mcommand.



     [1m45.88.  Xrange[0m


     The [1mset xrange [22mcommand sets the horizontal range that will be
     displayed.  A similar command exists for each of the other
     axes, as well as for the polar radius r and the parametric
     variables t, u, and v.

     Syntax:
           set xrange { [{{<min>}:{<max>}}] {{no}reverse}
     {{no}writeback} }
                      | restore
           show xrange

     where <min> and <max> terms are constants, expressions or an
     asterisk to set autoscaling.  If the data are time/date, you
     must give the range as a quoted string according to the [1mset[0m
     [1mtimefmt [22mformat.  Any value omitted will not be changed.

     The same syntax applies to [1myrange[22m, [1mzrange[22m, [1mx2range[22m, [1my2range[22m,
     [1mcbrange[22m, [1mrrange[22m, [1mtrange[22m, [1murange [22mand [1mvrange[22m.

     The [1mreverse [22moption reverses the direction of the axis, e.g.,
     [1mset xrange [0:1] reverse [22mwill produce an axis with 1 on the
     left and 0 on the right.  This is identical to the axis pro-
     duced by [1mset xrange [1:0][22m, of course.  [1mreverse [22mis intended pri-
     marily for use with [1mautoscale[22m.

     The [1mwriteback [22moption essentially saves the range found by
     [1mautoscale [22min the buffers that would be filled by [1mset xrange[22m.
     This is useful if you wish to plot several functions together
     but have the range determined by only some of them.  The










GNUPLOT 4.1                                                      201


     [1mwriteback [22moperation is performed during the [1mplot [22mexecution, so
     it must be specified before that command.  To restore, the last
     saved horizontal range use [1mset xrange restore[22m.  For example,

           set xrange [-10:10]
           set yrange [] writeback
           plot sin(x)
           set yrange restore
           replot x/2

     results in a yrange of [-1:1] as found only from the range of
     sin(x); the [-5:5] range of x/2 is ignored.  Executing [1mshow[0m
     [1myrange [22mafter each command in the above example should help you
     understand what is going on.

     In 2-d, [1mxrange [22mand [1myrange [22mdetermine the extent of the axes,
     [1mtrange [22mdetermines the range of the parametric variable in para-
     metric mode or the range of the angle in polar mode.  Similarly
     in parametric 3-d, [1mxrange[22m, [1myrange[22m, and [1mzrange [22mgovern the axes
     and [1murange [22mand [1mvrange [22mgovern the parametric variables.

     In polar mode, [1mrrange [22mdetermines the radial range plotted.
     <rmin> acts as an additive constant to the radius, whereas
     <rmax> acts as a clip to the radius---no point with radius
     greater than <rmax> will be plotted.  [1mxrange [22mand [1myrange [22mare
     affected---the ranges can be set as if the graph was of
     r(t)-rmin, with rmin added to all the labels.

     Any range may be partially or totally autoscaled, although it
     may not make sense to autoscale a parametric variable unless it
     is plotted with data.

     Ranges may also be specified on the [1mplot [22mcommand line.  A range
     given on the plot line will be used for that single [1mplot [22mcom-
     mand; a range given by a [1mset [22mcommand will be used for all sub-
     sequent plots that do not specify their own ranges.  The same
     holds true for [1msplot[22m.

     Examples:

     To set the xrange to the default:
           set xrange [-10:10]

     To set the yrange to increase downwards:
           set yrange [10:-10]

     To change zmax to 10 without affecting zmin (which may still be
     autoscaled):
           set zrange [:10]

     To autoscale xmin while leaving xmax unchanged:
           set xrange [*:]











GNUPLOT 4.1                                                      202


     [1m45.89.  Xtics[0m


     Fine control of the major (labelled) tics on the x axis is pos-
     sible with the [1mset xtics [22mcommand.  The tics may be turned off
     with the [1munset xtics [22mcommand, and may be turned on (the default
     state) with [1mset xtics[22m.  Similar commands control the major tics
     on the y, z, x2 and y2 axes.

     Syntax:
           set xtics {axis | border} {{no}mirror}
                     {in | out} {scale {default | <major>
     {,<minor>}}}
                     {{no}rotate {by <ang>}} {offset <offset> |
     nooffset}
                     {add}
                     {  autofreq
                      | <incr>
                      | <start>, <incr> {,<end>}
                      | ({"<label>"} <pos> {<level>}
     {,{"<label>"}...) }
                     { font "name{,<size>}" }
                     { textcolor <colorspec> }
           unset xtics
           show xtics

     The same syntax applies to [1mytics[22m, [1mztics[22m, [1mx2tics[22m, [1my2tics [22mand
     [1mcbtics[22m.

     [1maxis [22mor [1mborder [22mtells [1mgnuplot [22mto put the tics (both the tics
     themselves and the accompanying labels) along the axis or the
     border, respectively.  If the axis is very close to the border,
     the [1maxis [22moption will move the tic labels to outside the border.
     The relevant margin settings will usually be sized badly by the
     automatic layout algorithm in this case.

     [1mmirror [22mtells [1mgnuplot [22mto put unlabelled tics at the same posi-
     tions on the opposite border.  [1mnomirror [22mdoes what you think it
     does.

     [1min [22mand [1mout [22mchange the tic marks to be drawn inwards or out-
     wards.

     With [1mscale[22m, the size of the tic marks can be adjusted. If
     <minor> is not specified, it is 0.5*<major>.  The default size
     1.0 for major tics and 0.5 for minor tics is requested by [1mscale[0m
     [1mdefault[22m.

     [1mrotate [22masks [1mgnuplot [22mto rotate the text through 90 degrees,
     which will be done if the terminal driver in use supports text
     rotation.  [1mnorotate [22mcancels this. [1mrotate by <ang> [22masks for
     rotation by <ang> degrees, supported by some terminal types.











GNUPLOT 4.1                                                      203


     The defaults are [1mborder mirror norotate [22mfor tics on the x and y
     axes, and [1mborder nomirror norotate [22mfor tics on the x2 and y2
     axes.  For the z axis, the [1m{axis | border} [22moption is not avail-
     able and the default is [1mnomirror[22m.  If you do want to mirror the
     z-axis tics, you might want to create a bit more room for them
     with [1mset border[22m.

     The <offset> is specified by either x,y or x,y,z, and may be
     preceded by [1mfirst[22m, [1msecond[22m, [1mgraph[22m, [1mscreen[22m, or [1mcharacter [22mto
     select the coordinate system. <offset> is the offset of the
     tics texts from their default positions, while the default
     coordinate system is [1mcharacter[22m.  See [1mcoordinates [22mfor details.
     [1mnooffset [22mswitches off the offset.

     Example:

     Move xtics more closely to the plot.
           set xtics offset 0,graph 0.05

     [1mset xtics [22mwith no options restores the default border or axis
     if xtics are being displayed;  otherwise it has no effect.  Any
     previously specified tic frequency or position {and labels} are
     retained.

     Positions of the tics are calculated automatically by default
     or if the [1mautofreq [22moption is given; otherwise they may be spec-
     ified in either of two forms:

     The implicit <start>, <incr>, <end> form specifies that a
     series of tics will be plotted on the axis between the values
     <start> and <end> with an increment of <incr>.  If <end> is not
     given, it is assumed to be infinity.  The increment may be neg-
     ative.  If neither <start> nor <end> is given, <start> is
     assumed to be negative infinity, <end> is assumed to be posi-
     tive infinity, and the tics will be drawn at integral multiples
     of <incr>.  If the axis is logarithmic, the increment will be
     used as a multiplicative factor.

     If you specify to a negative <start> or <incr> after a numeri-
     cal value (e.g., [1mrotate by <angle> [22mor [1moffset <offset>[22m), the
     parser fails because it subtracts <start> or <incr> from that
     value.  As a workaround, specify [1m0-<start> [22mresp. [1m0-<incr> [22min
     that case.

     Example:
           set xtics border offset 0,0.5 -5,1,5
     Fails with 'invalid expression' at the last comma.
           set xtics border offset 0,0.5 0-5,1,5
     or
           set xtics offset 0,0.5 border -5,1,5
     Sets tics at the border, tics text with an offset of 0,0.5
     characters, and sets the start, increment, and end to -5, 1,
     and 5, as requested.










GNUPLOT 4.1                                                      204


     The [1mset grid [22moptions 'front', 'back' and 'layerdefault' affect
     the drawing order of the xtics, too.

     Examples:

     Make tics at 0, 0.5, 1, 1.5, ..., 9.5, 10.
           set xtics 0,.5,10

     Make tics at ..., -10, -5, 0, 5, 10, ...
           set xtics 5

     Make tics at 1, 100, 1e4, 1e6, 1e8.
           set logscale x; set xtics 1,100,1e8

     The explicit ("<label>" <pos> <level>, ...) form allows arbi-
     trary tic positions or non-numeric tic labels.  In this form,
     the tics do not need to be listed in numerical order.  Each tic
     has a position, optionally with a label.  Note that the label
     is a string enclosed by quotes.  It may be a constant string,
     such as "hello", may contain formatting information for con-
     verting the position into its label, such as "%3f clients", or
     may be empty, "".  See [1mset format [22mfor more information.  If no
     string is given, the default label (numerical) is used.

     An explicit tic mark has a third parameter, the "level".  The
     default is level 0, a major tic.  A level of 1 generates a
     minor tic.  If the level is specified, then the label must also
     be supplied.

     Examples:
           set xtics ("low" 0, "medium" 50, "high" 100)
           set xtics (1,2,4,8,16,32,64,128,256,512,1024)
           set ytics ("bottom" 0, "" 10, "top" 20)
           set ytics ("bottom" 0, "" 10 1, "top" 20)

     In the second example, all tics are labelled.  In the third,
     only the end tics are labelled.  In the fourth, the unlabeled
     tic is a minor tic.

     Normally if explicit tics are given, they are used instead of
     auto-generated tics. Conversely if you specify [1mset xtics auto[0m
     or the like it will erase any previously specified explicit
     tics. You can mix explicit and auto- generated tics by using
     the keyword [1madd[22m, which must appear before the tic style being
     added.

     Example:
           set xtics 0,.5,10
           set xtics add ("Pi" 3.14159)

     This will automatically generate tic marks every 0.5 along x,
     but will also add an explicit labeled tic mark at pi.











GNUPLOT 4.1                                                      205


     However they are specified, tics will only be plotted when in
     range.

     Format (or omission) of the tic labels is controlled by [1mset[0m
     [1mformat[22m, unless the explicit text of a label is included in the
     [1mset xtics ("<label>") [22mform.

     Minor (unlabelled) tics can be added automatically by the [1mset[0m
     [1mmxtics [22mcommand, or at explicit positions by the [1mset xtics (""[0m
     [1m<pos> 1, ...) [22mform.

     In case of timeseries data, position values must be given as
     quoted dates or times according to the format [1mtimefmt[22m.  If the
     <start>, <incr>, <end> form is used, <start> and <end> must be
     given according to [1mtimefmt[22m, but <incr> must be in seconds.
     Times will be written out according to the format given on [1mset[0m
     [1mformat[22m, however.

     Examples:
           set xdata time
           set timefmt "%d/%m"
           set format x "%b %d"
           set xrange ["01/12":"06/12"]
           set xtics "01/12", 172800, "05/12"

           set xdata time
           set timefmt "%d/%m"
           set format x "%b %d"
           set xrange ["01/12":"06/12"]
           set xtics ("01/12", "" "03/12", "05/12")
     Both of these will produce tics "Dec 1", "Dec 3", and "Dec 5",
     but in the second example the tic at "Dec 3" will be unla-
     belled.




     [1m45.90.  Xyplane[0m


     The [1mset xyplane [22mcommand adjusts the position at which the xy
     plane is drawn in a 3D plot.  The synonym "set ticslevel" is
     accepted for backwards compatibility.

     Syntax:
           set ticslevel <frac>
           set xyplane <frac>
           set xyplane at <zvalue>
           show xyplane

     The form [1mset ticslevel <frac> [22mplaces the xy plane below the
     range in Z, where the distance from the xy plane to Zmin is
     given as a fraction of the total range in z.  The default value










GNUPLOT 4.1                                                      206


     is 0.5.  Negative values are permitted, but tic labels on the
     three axes may overlap.

     To place the xy-plane at a position 'pos' on the z-axis, [1mtic-[0m
     [1mslevel [22mmay be set equal to  (pos - zmin) / (zmin - zmax).  How-
     ever, this position will change if the z range is changed.

     The alternative form [1mset xyplane at <zvalue> [22mfixes the place-
     ment of the xy plane at a specific Z value regardless of the
     current z range. Thus to force the x, y, and z axes to meet at
     a common origin one would specify [1mset xyplane at 0[22m.

     See also [1mset view[22m, and [1mset zeroaxis[22m.



     [1m45.91.  Xzeroaxis[0m


     The [1mset xzeroaxis [22mcommand draws a line at y = 0.  For details,
     please see [1mset zeroaxis[22m.



     [1m45.92.  Y2data[0m


     The [1mset y2data [22mcommand sets y2 (right-hand) axis data to time-
     series (dates/times).  Please see [1mset xdata[22m.



     [1m45.93.  Y2dtics[0m


     The [1mset y2dtics [22mcommand changes tics on the y2 (right-hand)
     axis to days of the week.  Please see [1mset xdtics [22mfor details.



     [1m45.94.  Y2label[0m


     The [1mset y2label [22mcommand sets the label for the y2 (right-hand)
     axis.  Please see [1mset xlabel[22m.



     [1m45.95.  Y2mtics[0m


     The [1mset y2mtics [22mcommand changes tics on the y2 (right-hand)
     axis to months of the year.  Please see [1mset xmtics [22mfor details.










GNUPLOT 4.1                                                      207


     [1m45.96.  Y2range[0m


     The [1mset y2range [22mcommand sets the vertical range that will be
     displayed on the y2 (right-hand) axis.  Please see [1mset xrange[0m
     for details.



     [1m45.97.  Y2tics[0m


     The [1mset y2tics [22mcommand controls major (labelled) tics on the y2
     (right-hand) axis.  Please see [1mset xtics [22mfor details.



     [1m45.98.  Y2zeroaxis[0m


     The [1mset y2zeroaxis [22mcommand draws a line at the origin of the y2
     (right-hand) axis (x2 = 0).  For details, please see [1mset[0m
     [1mzeroaxis[22m.



     [1m45.99.  Ydata[0m


     The [1mset ydata [22mcommands sets y-axis data to timeseries
     (dates/times).  Please see [1mset xdata[22m.



     [1m45.100.  Ydtics[0m


     The [1mset ydtics [22mcommand changes tics on the y axis to days of
     the week.  Please see [1mset xdtics [22mfor details.



     [1m45.101.  Ylabel[0m


     This command sets the label for the y axis.  Please see [1mset[0m
     [1mxlabel[22m.
















GNUPLOT 4.1                                                      208


     [1m45.102.  Ymtics[0m


     The [1mset ymtics [22mcommand changes tics on the y axis to months of
     the year.  Please see [1mset xmtics [22mfor details.



     [1m45.103.  Yrange[0m


     The [1mset yrange [22mcommand sets the vertical range that will be
     displayed on the y axis.  Please see [1mset xrange [22mfor details.



     [1m45.104.  Ytics[0m


     The [1mset ytics [22mcommand controls major (labelled) tics on the y
     axis.  Please see [1mset xtics [22mfor details.



     [1m45.105.  Yzeroaxis[0m


     The [1mset yzeroaxis [22mcommand draws a line at x = 0.  For details,
     please see [1mset zeroaxis[22m.



     [1m45.106.  Zdata[0m


     The [1mset zdata [22mcommand sets zaxis data to timeseries
     (dates/times).  Please see [1mset xdata[22m.



     [1m45.107.  Zdtics[0m


     The [1mset zdtics [22mcommand changes tics on the z axis to days of
     the week.  Please see [1mset xdtics [22mfor details.



     [1m45.108.  Zzeroaxis[0m


     The [1mset zzeroaxis [22mcommand draws a line through (x=0,y=0).  This
     has no effect on 2D plots, including splot with [1mset view map[22m.










GNUPLOT 4.1                                                      209


     For details, please see [1mset zeroaxis [22mand [1mset xyplane[22m.



     [1m45.109.  Cbdata[0m


     Set color box axis data to timeseries (dates/times).  Please
     see [1mset xdata[22m.



     [1m45.110.  Cbdtics[0m


     The [1mset cbdtics [22mcommand changes tics on the color box axis to
     days of the week. Please see [1mset xdtics [22mfor details.



     [1m45.111.  Zero[0m


     The [1mzero [22mvalue is the default threshold for values approaching
     0.0.

     Syntax:
           set zero <expression>
           show zero

     [1mgnuplot [22mwill not plot a point if its imaginary part is greater
     in magnitude than the [1mzero [22mthreshold.  This threshold is also
     used in various other parts of [1mgnuplot [22mas a (crude) numerical-
     error threshold.  The default [1mzero [22mvalue is 1e-8.  [1mzero [22mvalues
     larger than 1e-3 (the reciprocal of the number of pixels in a
     typical bitmap display) should probably be avoided, but it is
     not unreasonable to set [1mzero [22mto 0.0.



     [1m45.112.  Zeroaxis[0m


     The x axis may be drawn by [1mset xzeroaxis [22mand removed by [1munset[0m
     [1mxzeroaxis[22m.  Similar commands behave similarly for the y, x2,
     y2, and z axes.

     Syntax:
           set {x|x2|y|y2|z}zeroaxis { {linestyle | ls <line_style>}
                                      | { linetype | lt <line_type>}
                                        { linewidth | lw
     <line_width>}}
           unset {x|x2|y|y2|z}zeroaxis










GNUPLOT 4.1                                                      210


           show {x|y|z}zeroaxis


     By default, these options are off.  The selected zero axis is
     drawn with a line of type <line_type> and width <line_width>
     (if supported by the terminal driver currently in use), or a
     user-defined style <line_style>.

     If no linetype is specified, any zero axes selected will be
     drawn using the axis linetype (linetype 0).

     [1mset zeroaxis [22mis equivalent to [1mset xzeroaxis; set yzeroaxis[22m.
     Note that the z-axis must be set separately using [1mset zze-[0m
     [1mroaxis[22m.

     Examples:

     To simply have the y=0 axis drawn visibly:

            set xzeroaxis

     If you want a thick line in a different color or pattern,
     instead:

            set xzeroaxis linetype 3 linewidth 2.5



     [1m45.113.  Zlabel[0m


     This command sets the label for the z axis.  Please see [1mset[0m
     [1mxlabel[22m.



     [1m45.114.  Zmtics[0m


     The [1mset zmtics [22mcommand changes tics on the z axis to months of
     the year.  Please see [1mset xmtics [22mfor details.



     [1m45.115.  Zrange[0m


     The [1mset zrange [22mcommand sets the range that will be displayed on
     the z axis.  The zrange is used only by [1msplot [22mand is ignored by
     [1mplot[22m.  Please see [1mset xrange [22mfor details.













GNUPLOT 4.1                                                      211


     [1m45.116.  Ztics[0m


     The [1mset ztics [22mcommand controls major (labelled) tics on the z
     axis.  Please see [1mset xtics [22mfor details.



     [1m45.117.  Cblabel[0m


     This command sets the label for the color box axis.  Please see
     [1mset xlabel[22m.



     [1m45.118.  Cbmtics[0m


     The [1mset cbmtics [22mcommand changes tics on the color box axis to
     months of the year. Please see [1mset xmtics [22mfor details.



     [1m45.119.  Cbrange[0m


     The [1mset cbrange [22mcommand sets the range of values which are col-
     ored using the current [1mpalette [22mby styles [1mwith pm3d[22m, [1mwith image[0m
     and [1mwith palette[22m.  Values outside of the color range use color
     of the nearest extreme.

     If the cb-axis is autoscaled in [1msplot[22m, then the colorbox range
     is taken from [1mzrange[22m.  Points drawn in [1msplot ... pm3d|palette[0m
     can be filtered by using different [1mzrange [22mand [1mcbrange[22m.

     Please see [1mset xrange [22mfor details on [1mset cbrange [22msyntax. See
     also [1mset palette [22mand [1mset colorbox[22m.



     [1m45.120.  Cbtics[0m


     The [1mset cbtics [22mcommand controls major (labelled) tics on the
     color box axis.  Please see [1mset xtics [22mfor details.



[1m46.  Shell[0m













GNUPLOT 4.1                                                      212


The [1mshell [22mcommand spawns an interactive shell.  To return to [1mgnu-[0m
[1mplot[22m, type [1mlogout [22mif using VMS, [1mexit [22mor the END-OF-FILE character if
using Unix, [1mendcli [22mif using AmigaOS, or [1mexit [22mif using MS-DOS or
OS/2.

There are two ways of spawning a shell command: using [1msystem [22mcommand
or via [1m! [22m($ if using VMS). The former command takes a string as a
parameter and thus it can be used anywhere among other gnuplot com-
mands, while the latter syntax requires to be the only command on
the line. Control will return immediately to [1mgnuplot [22mafter this com-
mand is executed.  For example, in AmigaOS, MS-DOS or OS/2,

      ! dir
or
      system "dir"


prints a directory listing and then returns to [1mgnuplot[22m.


Other examples of the former syntax:
       system "date"; set time; plot "a.dat"
       print=1; if (print) replot; set out; system "lpr x.ps"

On an Atari, the [1m! [22mcommand first checks whether a shell is already
loaded and uses it, if available.  This is practical if [1mgnuplot [22mis
run from [1mgulam[22m, for example.



[1m47.  Splot[0m


[1msplot [22mis the command for drawing 3-d plots (well, actually projec-
tions on a 2-d surface, but you knew that).  It can create a plot
from functions or a data file in a manner very similar to the [1mplot[0m
command.

See [1mplot [22mfor features common to the [1mplot [22mcommand; only differences
are discussed in detail here.  Note specifically [1mplot[22m's [1maxes [22moption
is not available for [1msplot[22m.

Syntax:
      splot {<ranges>}
            <function> | "<datafile>" {datafile-modifiers}}
            {<title-spec>} {with <style>}
            {, {definitions,} <function> ...}

where either a <function> or the name of a data file enclosed in
quotes is supplied.  The function can be a mathematical expression,
or a triple of mathematical expressions in parametric mode.

By default [1msplot [22mdraws the xy plane completely below the plotted










GNUPLOT 4.1                                                      213


data.  The offset between the lowest ztic and the xy plane can be
changed by [1mset ticslevel[22m.  The orientation of a [1msplot [22mprojection is
controlled by [1mset view[22m.  See [1mset view [22mand [1mset ticslevel [22mfor more
information.

The syntax for setting ranges on the [1msplot [22mcommand is the same as
for [1mplot[22m.  In non-parametric mode, the order in which ranges must be
given is [1mxrange[22m, [1myrange[22m, and [1mzrange[22m.  In parametric mode, the order
is [1murange[22m, [1mvrange[22m, [1mxrange[22m, [1myrange[22m, and [1mzrange[22m.

The [1mtitle [22moption is the same as in [1mplot[22m.  The operation of [1mwith [22mis
also the same as in [1mplot[22m, except that the plotting styles available
to [1msplot [22mare limited to [1mlines[22m, [1mpoints[22m, [1mlinespoints[22m, [1mdots[22m, and
[1mimpulses[22m;  the error-bar capabilities of [1mplot [22mare not available for
[1msplot[22m.

The [1mdatafile [22moptions have more differences.

See also [1mshow plot[22m.




     [1m47.1.  Data-file[0m


     As for [1mplot[22m, discrete data contained in a file can be displayed
     by specifying the name of the data file, enclosed in quotes,
     on the [1msplot [22mcommand line.

     Syntax:
           splot '<file_name>' {binary <binary list>}
                               {matrix}
                               {index <index list>}
                               {every <every list>}
                               {using <using list>}

     The special filenames [1m"" [22mand [1m"-" [22mare permitted, as in [1mplot[22m.

     In brief, [1mbinary [22mand [1mmatrix [22mindicate that the data are in a
     special form, [1mindex [22mselects which data sets in a multi-data-set
     file are to be plotted, [1mevery [22mspecifies which datalines (sub-
     sets) within a single data set are to be plotted, and [1musing[0m
     determines how the columns within a single record are to be
     interpreted.

     The options [1mindex [22mand [1mevery [22mbehave the same way as with [1mplot[22m;
     [1musing [22mdoes so also, except that the [1musing [22mlist must provide
     three entries instead of two.

     The [1mplot [22moptions [1mthru [22mand [1msmooth [22mare not available for [1msplot[22m,
     but [1mcntrparam [22mand [1mdgrid3d [22mprovide limited smoothing capabili-
     ties.










GNUPLOT 4.1                                                      214


     Data file organization is essentially the same as for [1mplot[22m,
     except that each point is an (x,y,z) triple.  If only a single
     value is provided, it will be used for z, the datablock number
     will be used for y, and the index of the data point in the dat-
     ablock will be used for x.  If two or four values are provided,
     [1mgnuplot [22muses the last value for calculating the color in pm3d
     plots.  Three values are interpreted as an (x,y,z) triple.
     Additional values are generally used as errors, which can be
     used by [1mfit[22m.

     Single blank records separate datablocks in a [1msplot [22mdatafile;
     [1msplot [22mtreats datablocks as the equivalent of function y-iso-
     lines.  No line will join points separated by a blank record.
     If all datablocks contain the same number of points, [1mgnuplot[0m
     will draw cross-isolines between datablocks, connecting corre-
     sponding points.  This is termed "grid data", and is required
     for drawing a surface, for contouring ([1mset contour[22m) and hidden-
     line removal ([1mset hidden3d[22m). See also [1msplot grid_data[22m.

     It is no longer necessary to specify [1mparametric [22mmode for three-
     column [1msplot[22ms.




          [1m47.1.1.  Binary matrix[0m


          Gnuplot can read matrix binary files by use of the option
          [1mbinary [22mappearing without keyword qualifications unique to
          general binary, i.e., [1marray[22m, [1mrecord[22m, [1mformat[22m, or [1mfiletype[22m.
          Other general binary keywords for translation should also
          apply to matrix binary.  (See [1mbinary general [22mfor more
          details.)

          In previous versions, [1mgnuplot [22mdynamically detected binary
          data files.  It is now necessary to specify the keyword
          [1mbinary [22mdirectly after the filename.

          Single precision floats are stored in a binary file as
          follows:

                <N+1>  <y0>   <y1>   <y2>  ...  <yN>
                 <x0> <z0,0> <z0,1> <z0,2> ... <z0,N>
                 <x1> <z1,0> <z1,1> <z1,2> ... <z1,N>
                  :      :      :      :   ...    :

          which are converted into triplets:
                <x0> <y0> <z0,0>
                <x0> <y1> <z0,1>
                <x0> <y2> <z0,2>
                 :    :     :
                <x0> <yN> <z0,N>










GNUPLOT 4.1                                                      215


                <x1> <y0> <z1,0>
                <x1> <y1> <z1,1>
                 :    :     :

          These triplets are then converted into [1mgnuplot [22miso-curves
          and then [1mgnuplot [22mproceeds in the usual manner to do the
          rest of the plotting.

          A collection of matrix and vector manipulation routines
          (in C) is provided in [1mbinary.c[22m.  The routine to write
          binary data is

                int
          fwrite_matrix(file,m,nrl,nrl,ncl,nch,row_title,col-
          umn_title)

          An example of using these routines is provided in the file
          [1mbf_test.c[22m, which generates binary files for the demo file
          [1mdemo/binary.dem[22m.

          The [1mindex [22mkeyword is not supported, since the file format
          allows only one surface per file.  The [1mevery [22mand [1musing[0m
          filters are supported.  [1musing [22moperates as if the data were
          read in the above triplet form.

          See also [1mbinary general [22mand

          Binary File Splot Demo.



          [1m47.1.2.  Example datafile[0m


          A simple example of plotting a 3-d data file is

                splot 'datafile.dat'

          where the file "datafile.dat" might contain:

                # The valley of the Gnu.
                   0 0 10
                   0 1 10
                   0 2 10

                   1 0 10
                   1 1 5
                   1 2 10

                   2 0 10
                   2 1 1
                   2 2 10











GNUPLOT 4.1                                                      216


                   3 0 10
                   3 1 0
                   3 2 10

          Note that "datafile.dat" defines a 4 by 3 grid ( 4 rows of
          3 points each ).  Rows (datablocks) are separated by blank
          records.

          Note also that the x value is held constant within each
          dataline.  If you instead keep y constant, and plot with
          hidden-line removal enabled, you will find that the sur-
          face is drawn 'inside-out'.

          Actually for grid data it is not necessary to keep the x
          values constant within a datablock, nor is it necessary to
          keep the same sequence of y values.  [1mgnuplot [22mrequires only
          that the number of points be the same for each datablock.
          However since the surface mesh, from which contours are
          derived, connects sequentially corresponding points, the
          effect of an irregular grid on a surface plot is unpre-
          dictable and should be examined on a case-by-case basis.



          [1m47.1.3.  Matrix_ascii[0m


          The [1mmatrix [22mkeyword (without a sequent [1mbinary [22mkeyword) in
              {s}plot 'a.dat' matrix
          indicates that data are stored in an ascii numbers matrix
          format.

          The z-values are read in a row at a time, i. e.,
              z11 z12 z13 z14 ...
              z21 z22 z23 z24 ...
              z31 z32 z33 z34 ...
          and so forth.

          In 3D, the x- and y-indices of the matrix surface plot
          correspond to column and row indices of the matrix,
          respectively, being enumerated from 0. You can rescale or
          transform the axes as usual for a data file with three
          columns by means of x=$1, y=$2, z=$3. For example
              splot 'a.dat' matrix using (1+$1/100):(1+$2*10):3

          A blank line or comment line ends the matrix, and starts a
          new surface mesh.  You can select among the meshes inside
          a file by the [1mindex [22moption to the [1msplot [22mcommand, as usual.

          See [1mmatrix [22mfor examples of plotting rows and columns of
          the matrix in a 2D plot.












GNUPLOT 4.1                                                      217


          [1m47.1.4.  Matrix[0m


          Datafile can be in an ascii or binary matrix format. The
          [1mmatrix [22mflag indicates that the file is ascii, the [1mbinary[0m
          or [1mmatrix binary [22mstands for a binary format. For details,
          see [1mmatrix ascii [22mand [1mmatrix binary[22m.

          Basic usage in [1msplot[22m:
              splot 'a.dat' matrix
              splot 'a.gpbin' {matrix} binary
          Advanced usage in [1msplot[22m:
              splot 'a.dat' matrix using 1:2:3
              splot 'a.gpbin' {matrix} binary using 1:2:3
          allows to transform the axes coordinates and the z-data
          independently.

          Usage in [1mplot[22m:
              plot `a.dat` matrix
              plot `a.dat` matrix using 1:3
              plot 'a.gpbin' {matrix} binary using 1:3
          will plot rows of the matrix, while using 2:3 will plot
          matrix columns, and using 1:2 the point coordinates
          (rather useless). Applying the [1mevery [22moption you can spec-
          ify explicit rows and columns.

          Example -- rescale axes of a matrix in an ascii file:
              splot `a.dat` matrix using (1+$1):(1+$2*10):3

          Example -- plot the 3rd row of a matrix in an ascii file:
              plot 'a.dat' matrix using 1:3 every 1:999:1:2
          (rows are enumerated from 0, thus 2 instead of 3).



     [1m47.2.  Grid data[0m


     The 3D routines are designed for points in a grid format, with
     one sample, datapoint, at each mesh intersection; the data-
     points may originate from either evaluating a function, see [1mset[0m
     [1misosamples[22m, or reading a datafile, see [1msplot datafile[22m.  The
     term "isoline" is applied to the mesh lines for both functions
     and data.  Note that the mesh need not be rectangular in x and
     y, as it may be parameterized in u and v, see [1mset isosamples[22m.

     However, [1mgnuplot [22mdoes not require that format.  In the case of
     functions, 'samples' need not be equal to 'isosamples', i.e.,
     not every x-isoline sample need intersect a y-isoline. In the
     case of data files, if there are an equal number of scattered
     data points in each datablock, then "isolines" will connect the
     points in a datablock, and "cross-isolines" will connect the
     corresponding points in each datablock to generate a "surface".










GNUPLOT 4.1                                                      218


     In either case, contour and hidden3d modes may give different
     plots than if the points were in the intended format.  Scat-
     tered data can be converted to a {different} grid format with
     [1mset dgrid3d[22m.

     The contour code tests for z intensity along a line between a
     point on a y-isoline and the corresponding point in the next y-
     isoline.  Thus a [1msplot [22mcontour of a surface with samples on the
     x-isolines that do not coincide with a y-isoline intersection
     will ignore such samples. Try:
            set xrange [-pi/2:pi/2]; set yrange [-pi/2:pi/2]
            set style function lp
            set contour
            set isosamples 10,10; set samples 10,10;
            splot cos(x)*cos(y)
            set samples 4,10; replot
            set samples 10,4; replot




     [1m47.3.  Splot overview[0m


     [1msplot [22mcan display a surface as a collection of points, or by
     connecting those points.  As with [1mplot[22m, the points may be read
     from a data file or result from evaluation of a function at
     specified intervals, see [1mset isosamples[22m.  The surface may be
     approximated by connecting the points with straight line seg-
     ments, see [1mset surface[22m, in which case the surface can be made
     opaque with [1mset hidden3d.  [22mThe orientation from which the 3d
     surface is viewed can be changed with [1mset view[22m.

     Additionally, for points in a grid format, [1msplot [22mcan interpo-
     late points having a common amplitude (see [1mset contour[22m) and can
     then connect those new points to display contour lines, either
     directly with straight-line segments or smoothed lines (see [1mset[0m
     [1mcntrparam[22m).  Functions are already evaluated in a grid format,
     determined by [1mset isosamples [22mand [1mset samples[22m, while file data
     must either be in a grid format, as described in [1mdata-file[22m, or
     be used to generate a grid (see [1mset dgrid3d[22m).

     Contour lines may be displayed either on the surface or pro-
     jected onto the base.  The base projections of the contour
     lines may be written to a file, and then read with [1mplot[22m, to
     take advantage of [1mplot[22m's additional formatting capabilities.



[1m48.  System[0m













GNUPLOT 4.1                                                      219


[1msystem [22mspawns shell to execute a command. Please type [1mhelp shell [22mfor
more details.



[1m49.  Test[0m


This command graphically tests or presents terminal and palette
capabilities.

Syntax:
      test {terminal | palette [rgb|rbg|grb|gbr|brg|bgr]}

[1mtest [22mor [1mtest terminal [22mcreates a display of line and point styles and
other useful things appropriate for and supported by the [1mterminal[0m
you are just using.

[1mtest palette [22mdraws graphically profiles R(z),G(z),B(z), where
0<=z<=1, as calculated by the current color [1mpalette[22m. In other words,
it is a beautiful plot you would have to do yourself with the result
of [1mshow palette palette 256 float[22m.  The optional parameter, a permu-
tation of letters rgb, determines the sequence of r,g,b profiles
drawn one after the other --- try this yourself for [1mset palette[0m
[1mgray[22m. The default sequence is rgb.



[1m50.  Unset[0m


Options set using the [1mset [22mcommand may be returned to their default
state by issuing the corresponding [1munset [22mcommand.

Example:
      set xtics mirror rotate by -45 0,10,100
      ...
      unset xtics




[1m51.  Update[0m


This command writes the current values of the fit parameters into
the given file, formatted as an initial-value file (as described in
the [1mfit[22msection).  This is useful for saving the current values for
later use or for restarting a converged or stopped fit.

Syntax:
      update <filename> {<filename>}











GNUPLOT 4.1                                                      220


If a second filename is supplied, the updated values are written to
this file, and the original parameter file is left unmodified.

Otherwise, if the file already exists, [1mgnuplot [22mfirst renames it by
appending [1m.old [22mand then opens a new file.  That is, "[1mupdate 'fred'[22m"
behaves the same as "[1m!rename fred fred.old; update 'fred.old'[0m
[1m'fred'[22m".  [On DOS and other systems that use the twelve-character
"filename.ext" naming convention, "ext" will be "[1mold[22m" and "filename"
will be related (hopefully recognizably) to the initial name.
Renaming is not done at all on VMS systems, since they use file-ver-
sioning.]

Please see [1mfit [22mfor more information.




[1m52.  Terminal types[0m





[1m53.  Terminal[0m


Gnuplot supports a large number of output formats. These are
selected by choosing an appropriate terminal type, possibly with
additional modifying options. See [1mset terminal[22m.

This document may describe terminal types that are not available to
you because they were not configured or installed on your system. To
see a list of terminals available on a particular gnuplot installa-
tion, type 'set terminal' with no modifiers.





     [1m53.1.  Aed767[0m


     The [1maed512 [22mand [1maed767 [22mterminal drivers support AED graphics
     terminals.  The two drivers differ only in their horizontal
     ranges, which are 512 and 768 pixels, respectively.  Their ver-
     tical range is 575 pixels.  There are no options for these
     drivers.
















GNUPLOT 4.1                                                      221


     [1m53.2.  Aifm[0m



     NOTE: this terminal driver is outdated. Since Adobe Illustrator
     understands PostScript level 1 directly, you should use [1mset[0m
     [1mterminal post level1 [22minstead.

     Several options may be set in [1maifm[22m---the Adobe Illustrator 3.0+
     driver.

     Syntax:
           set terminal aifm {<color>} {"<fontname>"} {<fontsize>}

     <color> is either [1mcolor [22mor [1mmonochrome[22m; "<fontname>" is the name
     of a valid PostScript font; <fontsize> is the size of the font
     in PostScript points, before scaling by the [1mset size [22mcommand.
     Selecting [1mdefault [22msets all options to their default values:
     [1mmonochrome[22m, "Times-Roman", and 14pt.

     Since AI does not really support multiple pages, multiple
     graphs will be drawn directly on top of one another.  However,
     each graph will be grouped individually, making it easy to sep-
     arate them inside AI (just pick them up and move them).

     Examples:
           set term aifm
           set term aifm 22
           set size 0.7,1.4; set term aifm color "Times-Roman" 14



     [1m53.3.  Amiga[0m


     The [1mamiga [22mterminal, for Commodore Amiga computers, allows the
     user to plot either to a screen (default), or, if Kickstart 3.0
     or higher is installed, to a window on the current public
     screen. The font and its size can also be selected.

     Syntax:
           set terminal amiga {screen | window} {"<fontname>"}
     {<fontsize>}

     The default font is 8-point "topaz".

     The screen option uses a virtual screen, so it is possible that
     the graph will be larger than the screen.















GNUPLOT 4.1                                                      222


     [1m53.4.  Apollo[0m


     The [1mapollo [22mterminal driver supports the Apollo Graphics Primi-
     tive Resource with rescaling after window resizing.  It has no
     options.

     If a fixed-size window is desired, the [1mgpr [22mterminal may be used
     instead.



     [1m53.5.  Aqua[0m


     This terminal relies on AquaTerm.app for display on Mac OS X.

     Syntax:
           set terminal aqua {<n>} {title "<wintitle>"} {size <x>
     <y>}
                             {font "<fontname>{,<fontsize>}"}
                             {{no}enhanced} {solid|dashed} {dl
     <dashlength>}}

     where <n> is the number of the window to draw in (default is
     0), <wintitle> is the name shown in the title bar (default
     "Figure <n>"), <x> <y> is the size of the plot (default is
     846x594 pt = 11.75x8.25 in).

     Use <fontname> to specify the font to use (default is "Times-
     Roman"), and <fontsize> to specify the font size (default is
     14.0 pt). The old syntax {fname "<fontname>"} {fsize <font-
     size>} is still supported.

     The aqua terminal supports enhanced text mode (see [1menhanced[22m),
     except for overprint. Font support is limited to the fonts
     available on the system.  Character encoding can be selected by
     [1mset encoding [22mand currently supports iso_latin_1, iso_latin_2,
     cp1250, and default which equals UTF8.

     Lines can be drawn either solid or dashed, (default is solid)
     and the dash spacing can be modified by <dashlength> which is a
     multiplier > 0.




     [1m53.6.  Atari ST (via AES)[0m


     The [1matari [22mterminal has options to set the character size and
     the screen colors.











GNUPLOT 4.1                                                      223


     Syntax:
           set terminal atari {<fontsize>} {<col0> <col1> ...
     <col15>}

     The character size must appear if any colors are to be speci-
     fied.  Each of the (up to 16) colors is given as a three-digit
     hex number, where the digits represent RED, GREEN and BLUE (in
     that order).  The range of 0--15 is scaled to whatever color
     range the screen actually has.  On a normal ST screen, odd and
     even intensities are the same.

     Examples:
           set terminal atari 4    # use small (6x6) font
           set terminal atari 6 0  # set monochrome screen to white
     on black
           set terminal atari 13 0 fff f00 f0 f ff f0f
                      # set first seven colors to black, white, red,
     green,
                      # blue, cyan, and purple and use large font
     (8x16).

     Additionally, if an environment variable GNUCOLORS exists, its
     contents are interpreted as an options string, but an explicit
     terminal option takes precedence.



     [1m53.7.  Be[0m


     [1mgnuplot [22mprovides the [1mbe [22mterminal type for use with X servers.
     This terminal type is set automatically at startup if the [1mDIS-[0m
     [1mPLAY [22menvironment variable is set, if the [1mTERM [22menvironment vari-
     able is set to [1mxterm[22m, or if the [1m-display [22mcommand line option is
     used.

     Syntax:
               set terminal be {reset} {<n>}

     Multiple plot windows are supported: [1mset terminal be <n>[0m
     directs the output to plot window number n.  If n>0, the termi-
     nal number will be appended to the window title and the icon
     will be labeled [1mgplt <n>[22m.  The active window may distinguished
     by a change in cursor (from default to crosshair.)

     Plot windows remain open even when the [1mgnuplot [22mdriver is
     changed to a different device.  A plot window can be closed by
     pressing the letter q while that window has input focus, or by
     choosing [1mclose [22mfrom a window manager menu.  All plot windows
     can be closed by specifying [1mreset[22m, which actually terminates
     the subprocess which maintains the windows (unless [1m-persist [22mwas
     specified).











GNUPLOT 4.1                                                      224


     Plot windows will automatically be closed at the end of the
     session unless the [1m-persist [22moption was given.

     The size or aspect ratio of a plot may be changed by resizing
     the [1mgnuplot [22mwindow.

     Linewidths and pointsizes may be changed from within [1mgnuplot[0m
     with [1mset linestyle[22m.

     For terminal type [1mbe[22m, [1mgnuplot [22maccepts (when initialized) the
     standard X Toolkit options and resources such as geometry,
     font, and name from the command line arguments or a configura-
     tion file.  See the X(1) man page (or its equivalent) for a
     description of such options.

     A number of other [1mgnuplot [22moptions are available for the [1mbe [22mter-
     minal.  These may be specified either as command-line options
     when [1mgnuplot [22mis invoked or as resources in the configuration
     file ".Xdefaults".  They are set upon initialization and cannot
     be altered during a [1mgnuplot [22msession.




          [1m53.7.1.  Command-line_options[0m


          In addition to the X Toolkit options, the following
          options may be specified on the command line when starting
          [1mgnuplot [22mor as resources in your ".Xdefaults" file:



+---------------------------------------------------------------------------------+
|    `-mono`        forces monochrome rendering on color displays.                |
|    `-gray`        requests grayscale rendering on grayscale or color displays.  |
|                   (Grayscale displays receive monochrome rendering by default.) |
|    `-clear`       requests that the window be cleared momentarily before a      |
|                   new plot is displayed.                                        |
|    `-raise`       raises plot window after each plot                            |
|   `-noraise`      does not raise plot window after each plot                    |
|   `-persist`      plots windows survive after main gnuplot program exits        |
+---------------------------------------------------------------------------------+


The options are shown above in their command-line syntax.  When
entered as resources in ".Xdefaults", they require a different syn-
tax.

Example:
          gnuplot*gray: on

[1mgnuplot [22malso provides a command line option ([1m-pointsize <v>[22m) and a










GNUPLOT 4.1                                                      225


resource, [1mgnuplot*pointsize: <v>[22m, to control the size of points
plotted with the [1mpoints [22mplotting style.  The value [1mv [22mis a real num-
ber (greater than 0 and less than or equal to ten) used as a scaling
factor for point sizes.  For example, [1m-pointsize 2 [22muses points twice
the default size, and [1m-pointsize 0.5 [22muses points half the normal
size.



          [1m53.7.2.  Monochrome_options[0m


          For monochrome displays, [1mgnuplot [22mdoes not honor foreground
          or background colors.  The default is black-on-white.  [1m-rv[0m
          or [1mgnuplot*reverseVideo: on [22mrequests white-on-black.




          [1m53.7.3.  Color_resources[0m


          For color displays, [1mgnuplot [22mhonors the following resources
          (shown here with their default values) or the greyscale
          resources.  The values may be color names as listed in the
          BE rgb.txt file on your system, hexadecimal RGB color
          specifications (see BE documentation), or a color name
          followed by a comma and an [1mintensity [22mvalue from 0 to 1.
          For example, [1mblue, 0.5 [22mmeans a half intensity blue.



                 +--------------------------------+
                 |    gnuplot*background: white   |
                 |    gnuplot*textColor: black    |
                 |    gnuplot*borderColor: black  |
                 |    gnuplot*axisColor: black    |
                 |    gnuplot*line1Color: red     |
                 |    gnuplot*line2Color: green   |
                 |    gnuplot*line3Color: blue    |
                 |    gnuplot*line4Color: magenta |
                 |    gnuplot*line5Color: cyan    |
                 |    gnuplot*line6Color: sienna  |
                 |    gnuplot*line7Color: orange  |
                 |    gnuplot*line8Color: coral   |
                 +--------------------------------+



The command-line syntax for these is, for example,

Example:
          gnuplot -background coral










GNUPLOT 4.1                                                      226


          [1m53.7.4.  Grayscale_resources[0m


          When [1m-gray [22mis selected, [1mgnuplot [22mhonors the following
          resources for grayscale or color displays (shown here with
          their default values).  Note that the default background
          is black.



                  +-------------------------------+
                  |    gnuplot*background: black  |
                  |    gnuplot*textGray: white    |
                  |    gnuplot*borderGray: gray50 |
                  |    gnuplot*axisGray: gray50   |
                  |    gnuplot*line1Gray: gray100 |
                  |    gnuplot*line2Gray: gray60  |
                  |    gnuplot*line3Gray: gray80  |
                  |    gnuplot*line4Gray: gray40  |
                  |    gnuplot*line5Gray: gray90  |
                  |    gnuplot*line6Gray: gray50  |
                  |    gnuplot*line7Gray: gray70  |
                  |    gnuplot*line8Gray: gray30  |
                  +-------------------------------+






          [1m53.7.5.  Line_resources[0m


          [1mgnuplot [22mhonors the following resources for setting the
          width (in pixels) of plot lines (shown here with their
          default values.)  0 or 1 means a minimal width line of 1
          pixel width.  A value of 2 or 3 may improve the appearance
          of some plots.

























GNUPLOT 4.1                                                      227


                    +---------------------------+
                    |    gnuplot*borderWidth: 2 |
                    |    gnuplot*axisWidth: 0   |
                    |    gnuplot*line1Width: 0  |
                    |    gnuplot*line2Width: 0  |
                    |    gnuplot*line3Width: 0  |
                    |    gnuplot*line4Width: 0  |
                    |    gnuplot*line5Width: 0  |
                    |    gnuplot*line6Width: 0  |
                    |    gnuplot*line7Width: 0  |
                    |    gnuplot*line8Width: 0  |
                    +---------------------------+



[1mgnuplot [22mhonors the following resources for setting the dash style
used for plotting lines.  0 means a solid line.  A two-digit number
[1mjk [22m([1mj [22mand [1mk [22mare >= 1  and <= 9) means a dashed line with a repeated
pattern of [1mj [22mpixels on followed by [1mk [22mpixels off.  For example, '16'
is a "dotted" line with one pixel on followed by six pixels off.
More elaborate on/off patterns can be specified with a four-digit
value.  For example, '4441' is four on, four off, four on, one off.
The default values shown below are for monochrome displays or
monochrome rendering on color or grayscale displays.  For color dis-
plays, the default for each is 0 (solid line) except for [1maxisDashes[0m
which defaults to a '16' dotted line.



                  +------------------------------+
                  |    gnuplot*borderDashes: 0   |
                  |    gnuplot*axisDashes: 16    |
                  |    gnuplot*line1Dashes: 0    |
                  |    gnuplot*line2Dashes: 42   |
                  |    gnuplot*line3Dashes: 13   |
                  |    gnuplot*line4Dashes: 44   |
                  |    gnuplot*line5Dashes: 15   |
                  |    gnuplot*line6Dashes: 4441 |
                  |    gnuplot*line7Dashes: 42   |
                  |    gnuplot*line8Dashes: 13   |
                  +------------------------------+





     [1m53.8.  Cgi[0m


     The [1mcgi [22mand [1mhcgi [22mterminal drivers support SCO CGI drivers.
     [1mhcgi [22mis for printers; the environment variable CGIPRNT must be
     set.  [1mcgi [22mmay be used for either a display or hardcopy; if the
     environment variable CGIDISP is set, then that display is used.










GNUPLOT 4.1                                                      228


     Otherwise CGIPRNT is used.

     These terminals have no options.



     [1m53.9.  Cgm[0m


     The [1mcgm [22mterminal generates a Computer Graphics Metafile, Ver-
     sion 1.  This file format is a subset of the ANSI X3.122-1986
     standard entitled "Computer Graphics - Metafile for the Storage
     and Transfer of Picture Description Information".  Several
     options may be set in [1mcgm[22m.

     Syntax:
           set terminal cgm {<mode>} {<color>} {<rotation>} {solid |
     dashed}
                            {width <plot_width>} {linewidth
     <line_width>}
                            {"<font>"} {<fontsize>}
                            {<color0> <color1> <color2> ...}

     where <mode> is [1mlandscape[22m, [1mportrait[22m, or [1mdefault[22m; <color> is
     either [1mcolor [22mor [1mmonochrome[22m; <rotation> is either [1mrotate [22mor
     [1mnorotate[22m; [1msolid [22mdraws all curves with solid lines, overriding
     any dashed patterns; <plot_width> is the assumed width of the
     plot in points; <line_width> is the line width in points
     (default 1); <font> is the name of a font; and <fontsize> is
     the size of the font in points (default 12).

     By default, [1mcgm [22muses rotated text for the Y axis label.

     The first six options can be in any order.  Selecting [1mdefault[0m
     sets all options to their default values.

     Each color must be of the form 'xrrggbb', where x is the lit-
     eral character 'x' and 'rrggbb' are the red, green and blue
     components in hex.  For example, 'x00ff00' is green.  The back-
     ground color is set first, then the plotting colors.

     Examples:
           set terminal cgm landscape color rotate dashed width 432
     \
                          linewidth 1  'Helvetica Bold' 12       #
     defaults
           set terminal cgm linewidth 2  14  # wider lines & larger
     font
           set terminal cgm portrait "Times Italic" 12
           set terminal cgm color solid      # no pesky dashes!













GNUPLOT 4.1                                                      229


          [1m53.9.1.  Font[0m


          The first part of a Computer Graphics Metafile, the
          metafile description, includes a font table.  In the pic-
          ture body, a font is designated by an index into this ta-
          ble.  By default, this terminal generates a table with the
          following 35 fonts, plus six more with [1mitalic [22mreplaced by
          [1moblique[22m, or vice-versa (since at least the Microsoft
          Office and Corel Draw CGM import filters treat [1mitalic [22mand
          [1moblique [22mas equivalent):




















































GNUPLOT 4.1                                                      230


                +-----------------------------------+
                |        CGM fonts                  |
                +-----------------------------------+
                |        Helvetica                  |
                |        Helvetica Bold             |
                |        Helvetica Oblique          |
                |        Helvetica Bold Oblique     |
                |        Times Roman                |
                |        Times Bold                 |
                |        Times Italic               |
                |        Times Bold Italic          |
                |        Courier                    |
                |        Courier Bold               |
                |        Courier Oblique            |
                |        Courier Bold Oblique       |
                |        Symbol                     |
                |        Hershey/Cartographic_Roman |
                |        Hershey/Cartographic_Greek |
                |        Hershey/Simplex_Roman      |
                |        Hershey/Simplex_Greek      |
                |        Hershey/Simplex_Script     |
                |        Hershey/Complex_Roman      |
                |        Hershey/Complex_Greek      |
                |        Hershey/Complex_Script     |
                |        Hershey/Complex_Italic     |
                |        Hershey/Complex_Cyrillic   |
                |        Hershey/Duplex_Roman       |
                |        Hershey/Triplex_Roman      |
                |        Hershey/Triplex_Italic     |
                |        Hershey/Gothic_German      |
                |        Hershey/Gothic_English     |
                |        Hershey/Gothic_Italian     |
                |        Hershey/Symbol_Set_1       |
                |        Hershey/Symbol_Set_2       |
                |        Hershey/Symbol_Math        |
                |        ZapfDingbats               |
                |        Script                     |
                |        15                         |
                +-----------------------------------+


The first thirteen of these fonts are required for WebCGM.  The
Microsoft Office CGM import filter implements the 13 standard fonts
listed above, and also 'ZapfDingbats' and 'Script'.  However, the
script font may only be accessed under the name '15'.  For more on
Microsoft import filter font substitutions, check its help file
which you may find here:
  C:\Program Files\Microsoft Office\Office\Cgmimp32.hlp
and/or its configuration file, which you may find here:
  C:\Program Files\Common Files\Microsoft
Shared\Grphflt\Cgmimp32.cfg

In the [1mset term [22mcommand, you may specify a font name which does not










GNUPLOT 4.1                                                      231


appear in the default font table.  In that case, a new font table is
constructed with the specified font as its first entry. You must
ensure that the spelling, capitalization, and spacing of the name
are appropriate for the application that will read the CGM file.
(Gnuplot and any MIL-D-28003A compliant application ignore case in
font names.)  If you need to add several new fonts, use several [1mset[0m
[1mterm [22mcommands.

Example:
      set terminal cgm 'Old English'
      set terminal cgm 'Tengwar'
      set terminal cgm 'Arabic'
      set output 'myfile.cgm'
      plot ...
      set output

You cannot introduce a new font in a [1mset label [22mcommand.



          [1m53.9.2.  Fontsize[0m


          Fonts are scaled assuming the page is 6 inches wide.  If
          the [1msize [22mcommand is used to change the aspect ratio of the
          page or the CGM file is converted to a different width,
          the resulting font sizes will be scaled up or down accord-
          ingly.  To change the assumed width, use the [1mwidth [22moption.



          [1m53.9.3.  Linewidth[0m


          The [1mlinewidth [22moption sets the width of lines in pt.  The
          default width is 1 pt.  Scaling is affected by the actual
          width of the page, as discussed under the [1mfontsize [22mand
          [1mwidth [22moptions.



          [1m53.9.4.  Rotate[0m


          The [1mnorotate [22moption may be used to disable text rotation.
          For example, the CGM input filter for Word for Windows
          6.0c can accept rotated text, but the DRAW editor within
          Word cannot.  If you edit a graph (for example, to label a
          curve), all rotated text is restored to horizontal.  The Y
          axis label will then extend beyond the clip boundary.
          With [1mnorotate[22m, the Y axis label starts in a less attrac-
          tive location, but the page can be edited without damage.
          The [1mrotate [22moption confirms the default behavior.










GNUPLOT 4.1                                                      232


          [1m53.9.5.  Solid[0m


          The [1msolid [22moption may be used to disable dashed line styles
          in the plots.  This is useful when color is enabled and
          the dashing of the lines detracts from the appearance of
          the plot. The [1mdashed [22moption confirms the default behavior,
          which gives a different dash pattern to each curve.



          [1m53.9.6.  Size[0m


          Default size of a CGM plot is 32599 units wide and 23457
          units high for landscape, or 23457 units wide by 32599
          units high for portrait.



          [1m53.9.7.  Width[0m


          All distances in the CGM file are in abstract units.  The
          application that reads the file determines the size of the
          final plot.  By default, the width of the final plot is
          assumed to be 6 inches (15.24 cm).  This distance is used
          to calculate the correct font size, and may be changed
          with the [1mwidth [22moption.  The keyword should be followed by
          the width in points.  (Here, a point is 1/72 inch, as in
          PostScript.  This unit is known as a "big point" in TeX.)
          Gnuplot [1mexpressions [22mcan be used to convert from other
          units.

          Example:
                set terminal cgm width 432            # default
                set terminal cgm width 6*72           # same as
          above
                set terminal cgm width 10/2.54*72     # 10 cm wide



          [1m53.9.8.  Nofontlist[0m


          The default font table includes the fonts recommended for
          WebCGM, which are compatible with the Computer Graphics
          Metafile input filter for Microsoft Office and Corel Draw.
          Another application might use different fonts and/or dif-
          ferent font names, which may not be documented.  As a
          workaround, the [1mnofontlist [22moption deletes the font table
          from the CGM file.  In this case, the reading application
          should use a default table.  Gnuplot will still use its










GNUPLOT 4.1                                                      233


          own default font table to select font indices.  Thus,
          'Helvetica' will give you an index of 1, which should get
          you the first entry in your application's default font ta-
          ble. 'Helvetica Bold' will give you its second entry, etc.

          The former [1mwinword6 [22moption is now a deprecated synonym for
          [1mnofontlist[22m.  The problems involving the color and font
          tables that the [1mwinword6 [22moption was intended to work
          around turned out to be gnuplot bugs which have now been
          fixed.



     [1m53.10.  Corel[0m


     The [1mcorel [22mterminal driver supports CorelDraw.

     Syntax:
           set terminal corel {  default
                               | {monochrome | color
                                    {"<font>" {<fontsize>
                                       {<xsize> <ysize> {<linewidth>
     }}}}}

     where the fontsize and linewidth are specified in points and
     the sizes in inches.  The defaults are monochrome, "Switzer-
     landLight", 22, 8.2, 10 and 1.2.



     [1m53.11.  Debug[0m


     This terminal is provided to allow for the debugging of [1mgnu-[0m
     [1mplot[22m.  It is likely to be of use only for users who are modify-
     ing the source code.



     [1m53.12.  Dospc[0m


     The [1mdospc [22mterminal driver supports PCs with arbitrary graphics
     boards, which will be automatically detected.  It should be
     used only if you are not using the gcc or Zortec C/C++ compil-
     ers.
















GNUPLOT 4.1                                                      234


     [1m53.13.  Dumb[0m


     The [1mdumb [22mterminal driver has an optional size specification and
     trailing linefeed control.

     Syntax:
           set terminal dumb {[no]feed} {<xsize> <ysize>}
                             {[no]enhanced}

     where <xsize> and <ysize> set the size of the dumb terminals.
     Default is 79 by 24. The last newline is printed only if [1mfeed[0m
     is enabled.

     Examples:
           set term dumb nofeed
           set term dumb 79 49 # VGA screen---why would anyone do
     that?



     [1m53.14.  Dxf[0m


     The [1mdxf [22mterminal driver creates pictures that can be imported
     into AutoCad (Release 10.x).  It has no options of its own, but
     some features of its plots may be modified by other means.  The
     default size is 120x80 AutoCad units, which can be changed by
     [1mset size[22m.  [1mdxf [22muses seven colors (white, red, yellow, green,
     cyan, blue and magenta), which can be changed only by modifying
     the source file.  If a black-and-white plotting device is used,
     the colors are mapped to differing line thicknesses.  See the
     description of the AutoCad print/plot command.



     [1m53.15.  Dxy800a[0m


     This terminal driver supports the Roland DXY800A plotter.  It
     has no options.



     [1m53.16.  Eepic[0m


     The [1meepic [22mterminal driver supports the extended LaTeX picture
     environment.  It is an alternative to the [1mlatex [22mdriver.

     The output of this terminal is intended for use with the
     "eepic.sty" macro package for LaTeX.  To use it, you need
     "eepic.sty", "epic.sty" and a printer driver that supports the










GNUPLOT 4.1                                                      235


     "tpic" \specials.  If your printer driver doesn't support those
     \specials, "eepicemu.sty" will enable you to use some of them.
     dvips and dvipdfm do support the "tpic" \specials.

     Syntax:
        set terminal eepic {color, dashed, rotate, small, tiny,
     default, <fontsize>}

     Options: You can give options in any order you wish.  'color'
     causes gnuplot to produce \color{...} commands so that the
     graphs are colored. Using this option, you must include \usepa-
     ckage{color} in the preambel of your latex document.  'dashed'
     will allow dashed line types; without this option, only solid
     lines with varying thickness will be used.  'dashed' and
     'color' are mutually exclusive; if 'color' is specified, then
     'dashed' will be ignored.  'rotate' will enable true rotated
     text (by 90 degrees). Otherwise, rotated text will be typeset
     with letters stacked above each other. If you use this option
     you must include \usepackage{graphicx} in the preamble.
     'small' will use \scriptsize symbols as point markers (Probably
     does not work with TeX, only LaTeX2e). Default is to use the
     default math size.  'tiny' uses \scriptscriptstyle symbols.
     'default' resets all options to their defaults = no color, no
     dashed lines, pseudo-rotated (stacked) text, large point sym-
     bols.  <fontsize> is a number which specifies the font size
     inside the picture environment; the unit is pt (points), i.e.,
     10 pt equals approx. 3.5 mm.  If fontsize is not specified,
     then all text inside the picture will be set in \footnotesize.

     Notes: Remember to escape the # character (or other chars mean-
     ingful to (La-)TeX) by \\ (2 backslashes).  It seems that
     dashed lines become solid lines when the vertices of a plot are
     too close. (I do not know if that is a general problem with the
     tpic specials, or if it is caused by a bug in eepic.sty or
     dvips/dvipdfm.)  The default size of an eepic plot is 5x3
     inches, which can be scaled by 'set size a,b'.  Points, among
     other things, are drawn using the LaTeX commands "\Diamond",
     "\Box", etc.  These commands no longer belong to the LaTeX2e
     core; they are included in the latexsym package, which is part
     of the base distribution and thus part of any LaTeX implementa-
     tion. Please do not forget to use this package.  Instead of
     latexsym, you can also include the amssymb package.  All
     drivers for LaTeX offer a special way of controlling text posi-
     tioning: If any text string begins with '{', you also need to
     include a '}' at the end of the text, and the whole text will
     be centered both horizontally and vertically.  If the text
     string begins with '[', you need to follow this with a position
     specification (up to two out of t,b,l,r), ']{', the text
     itself, and finally '}'.  The text itself may be anything LaTeX
     can typeset as an LR-box.  '\rule{}{}'s may help for best posi-
     tioning.

     Examples: set term eepic










GNUPLOT 4.1                                                      236


       output graphs as eepic macros inside a picture environment;
       \input the resulting file in your LaTeX document.
     set term eepic color tiny rotate 8
       eepic macros with \color macros, \scripscriptsize point mark-
     ers,
       true rotated text, and all text set with 8pt.

     About label positioning: Use gnuplot defaults (mostly sensible,
     but sometimes not really best):
            set title '\LaTeX\ -- $ \gamma $'
     Force centering both horizontally and vertically:
            set label '{\LaTeX\ -- $ \gamma $}' at 0,0
     Specify own positioning (top here):
            set xlabel '[t]{\LaTeX\ -- $ \gamma $}'
     The other label -- account for long ticlabels:
            set ylabel '[r]{\LaTeX\ -- $ \gamma $\rule{7mm}{0pt}}'



     [1m53.17.  Emf[0m


     The [1memf [22mterminal generates an Enhanced Metafile Format file.
     This file format is the metafile standard on MS Win32 Systems.

     Syntax:
           set terminal emf {<color>} {solid | dashed} {linewidth
     <X>}
                            {size XX,YY}
                            {"<fontname>"} {<fontsize>}    #old syn-
     tax
                            {font "<fontname>,<fontsize>"} #new syn-
     tax

     <color> is either [1mcolor [22mor [1mmonochrome[22m; [1msolid [22mdraws all curves
     with solid lines, overriding any dashed patterns; [1mlinewidth[0m
     [1m<factor> [22mmultiplies all line widths by this factor.  <font> is
     the name of a font; and [1m<fontsize> [22mis the size of the font in
     points.

     The nominal size of the output image default to 1024x768 in
     arbitrary units. You may specify a different nominal size using
     the [1msize [22moption.

     The first two options can be in any order.  Selecting [1mdefault[0m
     sets all options to their default values.

     Examples:
           set terminal emf 'Times Roman Italic' 12
           set terminal emf color solid    # no pesky dashes!













GNUPLOT 4.1                                                      237


     [1m53.18.  Emxvga[0m


     The [1memxvga[22m, [1memxvesa [22mand [1mvgal [22mterminal drivers support PCs with
     SVGA, vesa SVGA and VGA graphics boards, respectively.  They
     are intended to be compiled with "emx-gcc" under either DOS or
     OS/2.  They also need VESA and SVGAKIT maintained by Johannes
     Martin (JMARTIN@GOOFY.ZDV.UNI-MAINZ.DE) with additions by David
     J. Liu (liu@phri.nyu.edu).

     Syntax:
           set terminal emxvga
           set terminal emxvesa {vesa-mode}
           set terminal vgal

     The only option is the vesa mode for [1memxvesa[22m, which defaults to
     G640x480x256.



     [1m53.19.  Epslatex[0m


     The [1mepslatex [22mdriver generates output for further processing by
     LaTeX.

     Syntax:
           set terminal epslatex   {default}
           set terminal epslatex   {standalone | input}
                                   {oldstyle | newstyle}
                                   {level1 | leveldefault}
                                   {color | colour | monochrome}
                                   {solid | dashed}
                                   {dashlength | dl <DL>}
                                   {linewidth | lw <LW>}
                                   {rounded | butt}
                                   {palfuncparam <samples>{,<maxde-
     viation>}}
                                   {size <XX>{unit},<YY>{unit}}
                                   {header <header> | noheader}
                                   {blacktext | colortext | colour-
     text}
                                   {{font} "fontname{,fontsize}"
     {<fontsize>}}

     The epslatex terminal prints a plot as [1mterminal postscript eps[0m
     but transfers the texts to LaTeX instead of including in the
     PostScript code. Thus, many options are the same as in the
     [1mpostscript terminal[22m.

     From version 4.0 to 4.2, some changes have been invoked into
     the default appearance of the epslatex terminal to reach better
     consistency with the postscript terminal:  The plot size has










GNUPLOT 4.1                                                      238


     been changed from 5 x 3 inches to 5 x 3.5 inches;  the charac-
     ter width is now estimated to be 60% of the font size while the
     old epslatex terminal used 50%;  now, the larger number of
     postscript linetypes and symbols are used.  To reach an appear-
     ance that is nearly identical to the old one specify the option
     [1moldstyle[22m. (In fact some small differences remain: the symbol
     sizes are slightly different, the tics are half as large as in
     the old terminal which can be changed using [1mset tics scale[22m, and
     the arrows have all features as in the postscript terminal.)

     If you see the error message
           "Can't find PostScript prologue file ... "
     Please see and follow the instructions in [1mpostscript prologue[22m.

     The option [1mcolor [22menables color, while [1mmonochrome [22mprefers black
     and white drawing elements. Further, [1mmonochrome [22muses gray
     [1mpalette [22mbut it does not change color of objects specified with
     an explicit [1mcolorspec[22m.  [1msolid [22mdraws all plots with solid lines,
     overriding any dashed patterns.  [1mdashlength [22mor [1mdl [22mscales the
     length of the dashed-line segments by <DL>, which is a float-
     ing-point number greater than zero.  [1mlinewidth [22mor [1mlw [22mscales all
     linewidths by <LW>.

     By default the generated PostScript code uses language features
     that were introduced in PostScript Level 2, notably filters and
     pattern-fill of irregular objects such as filledcurves.
     PostScript Level 2 features are conditionally protected so that
     PostScript Level 1 interpreters do not issue errors but,
     rather, display a message or a PostScript Level 1 approxima-
     tion.  The [1mlevel1 [22moption substitutes PostScript Level 1 approx-
     imations of these features and uses no PostScript Level 2 code.
     This may be required by some old printers and old versions of
     Adobe Illustrator.  The flag [1mlevel1 [22mcan be toggled later by
     editing a single line in the PostScript output file to force
     PostScript Level 1 interpretation.  In the case of files con-
     taining level 2 code, the above features will not appear or
     will be replaced by a note when this flag is set or when the
     interpreting program does not indicate that it understands
     level 2 PostScript or higher.

     [1mrounded [22msets line caps and line joins to be rounded; [1mbutt [22mis
     the default, butt caps and mitered joins;

     [1mpalfuncparam [22mcontrols how [1mset palette functions [22mare encoded as
     gradients in the output. Analytic color component functions
     (set via [1mset palette functions[22m) are encoded as linear interpo-
     lated gradients in the postscript output:  The color component
     functions are sampled at <samples> points and all points are
     removed from this gradient which can be removed without chang-
     ing the resulting colors by more than <maxdeviation>. For
     almost every useful palette you may savely leave the defaults
     of <samples>=2000 and <maxdeviation>=0.003 untouched.











GNUPLOT 4.1                                                      239


     The default size for postscript output is 10 inches x 7 inches.
     The default for eps output is 5 x 3.5 inches.  The [1msize [22moption
     changes this to whatever the user requests. By default the X
     and Y sizes are taken to be in inches, but other units are pos-
     sibly (currently only cm). The BoundingBox of the plot is cor-
     rectly adjusted to contain the resized image.  Screen coordi-
     nates always run from 0.0 to 1.0 along the full length of the
     plot edges as specified by the [1msize [22moption.  NB: [1mthis is a[0m
     [1mchange from the previously recommended method of using the set[0m
     [1msize command prior to setting the terminal type[22m.  The old
     method left the BoundingBox unchanged and screen coordinates
     did not correspond to the actual limits of the plot.

     [1mblacktext [22mforces all text to be written in black even in color
     mode;

     The epslatex driver offers a special way of controlling text
     positioning: (a) If any text string begins with '{', you also
     need to include a '}' at the end of the text, and the whole
     text will be centered both horizontally and vertically by
     LaTeX.  (b) If the text string begins with '[', you need to
     continue it with: a position specification (up to two out of
     t,b,l,r,c), ']{', the text itself, and finally, '}'. The text
     itself may be anything LaTeX can typeset as an LR-box.
     \rule{}{}'s may help for best positioning.  See also the docu-
     mentation for the [1mpslatex [22mterminal driver.  To create multiline
     labels, use \shortstack, for example
        set ylabel '[r]{\shortstack{first line \\ second line}}'

     The [1mback [22moption of [1mset label [22mcommands is handled slightly dif-
     ferent than in other terminals. Labels using 'back' are printed
     behind all other elements of the plot while labels using
     'front' are printed above everything else.

     The driver produces two different files, one for the eps part
     of the figure and one for the LaTeX part. The name of the LaTeX
     file is taken from the [1mset output [22mcommand. The name of the eps
     file is derived by replacing the file extension (normally [1m.tex[22m)
     with [1m.eps [22minstead.  There is no LaTeX output if no output file
     is given!  Remember to close the [1moutput file [22mbefore next plot
     unless in [1mmultiplot [22mmode.

     In your LaTeX documents use '\input{filename}' to include the
     figure.  The [1m.eps [22mfile is included by the command \include-
     graphics{...}, so you must also include \usepackage{graphicx}
     in the LaTeX preamble.  If you want to use coloured text
     (option [1mtextcolour[22m) you also have to include \usepackage{color}
     in the LaTeX preamble.

     Pdf files can be made from the eps file using 'epstopdf'. If
     the graphics package is properly configured, the LaTeX files
     can also be processed by pdflatex without changes, using the
     pdf files instead of the eps files.  The behaviour concerning










GNUPLOT 4.1                                                      240


     font selection depends on the header mode.  In all cases, the
     given font size is used for the calculation of proper spacing.
     When not using the [1mstandalone [22mmode the actual LaTeX font and
     font size at the point of inclusion is taken, so use LaTeX com-
     mands for changing fonts. If you use e.g. 12pt as font size for
     your LaTeX document, use '"" 12' as options. The font name is
     ignored. If using [1mstandalone [22mthe given font and font size are
     used, see below for a detailed description.

     If text is printed coloured is controlled by the TeX booleans
     \ifGPcolor and \ifGPblacktext. Only if \ifGPcolor is true and
     \ifGPblacktext is false, text is printed coloured. You may
     either change them in the generated TeX file or provide them
     globally in your TeX file, for example by using
        \newif\ifGPblacktext
        \GPblacktexttrue
     in the preamble of your document. The local assignment is only
     done if no global value is given.

     When using the epslatex terminal give the name of the TeX file
     in the [1mset output [22mcommand including the file extension (nor-
     mally ".tex").  The eps filename is generated by replacing the
     extension by ".eps".

     If using the [1mstandalone [22mmode a complete LaTeX header is added
     to the LaTeX file; and "-inc" is added to the filename of the
     eps file.  The [1mstandalone [22mmode generates a TeX file that pro-
     duces output with the correct size when using dvips, pdfTeX, or
     VTeX.  The default, [1minput[22m, generates a file that has to be
     included into a LaTeX document using the \input command.

     If a font other than "" or "default" is given it is interpreted
     as LaTeX font name.  It contains up to three parts, separated
     by a comma: 'fontname,fontseries,fontshape'.  If the default
     fontshape or fontseries are requested, they can be omitted.
     Thus, the real syntax for the fontname is '[font-
     name][,fontseries][,fontshape]'.  The naming convention for all
     parts is given by the LaTeX font scheme.  The fontname is 3 to
     4 characters long and is built as follows: One character for
     the font vendor, two characters for the name of the font, and
     optionally one additional character for special fonts, e.g.,
     'j' for fonts with old-style numerals or 'x' for expert fonts.
     The names of many fonts is described in
               http://www.tug.org/fontname/fontname.pdf
     For example, 'cmr' stands for Computer Modern Roman, 'ptm' for
     Times-Roman, and 'phv' for Helvetica.  The font series denotes
     the thickness of the glyphs, in most cases 'm' for normal
     ("medium") and 'bx' or 'b' for bold fonts.  The font shape is
     'n' for upright, 'it' for italics, 'sl' for slanted, or 'sc'
     for small caps, in general.  Some fonts may provide different
     font series or shapes.

     Examples:










GNUPLOT 4.1                                                      241


     Use Times-Roman boldface (with the same shape as in the sur-
     rounding text):
           set terminal epslatex 'ptm,bx'
     Use Helvetica, boldface, italics:
           set terminal epslatex 'phv,bx,it'
     Continue to use the surrounding font in slanted shape:
           set terminal epslatex ',,sl'
     Use small capitals:
           set terminal epslatex ',,sc'

     By this method, only text fonts are changed. If you also want
     to change the math fonts you have to use the "gnuplot.cfg" file
     or the [1mheader [22moption, described below.

     In standalone mode, the font size is taken from the given font
     size in the [1mset terminal [22mcommand. To be able to use a specified
     font size, a file "size<size>.clo" has to reside in the LaTeX
     search path.  By default, 10pt, 11pt, and 12pt are supported.
     If the package "extsizes" is installed, 8pt, 9pt, 14pt, 17pt,
     and 20pt are added.

     The [1mheader [22moption takes a string as argument.  This string is
     written into the generated LaTeX file.  If using the [1mstandalone[0m
     mode, it is written into the preamble, directly before the
     \begin{document} command.  In the [1minput [22mmode, it is placed
     directly after the \begingroup command to ensure that all set-
     tings are local to the plot.

     Examples:

     Use T1 fontencoding, change the text and math font to Times-
     Roman as well as the sans-serif font to Helvetica:
         set terminal epslatex standalone header \
         "\\usepackage[T1]{fontenc}\n\\usepackage{mathptmx}\n\\usep-
     ackage{helvet}"
     Use a boldface font in the plot, not influencing the text out-
     side the plot:
         set terminal epslatex input header "\\bfseries"

     If the file "gnuplot.cfg" is found by LaTeX it is input in the
     preamble the LaTeX document, when using [1mstandalone [22mmode.  It
     can be used for further settings, e.g., changing the document
     font to Times-Roman, Helvetica, and Courier, including math
     fonts (handled by "mathptmx.sty"):
           \usepackage{mathptmx}
           \usepackage[scaled=0.92]{helvet}
           \usepackage{courier}
     The file "gnuplot.cfg" is loaded before the header information
     given by the [1mheader [22mcommand.  Thus, you can use [1mheader [22mto over-
     write some of settings performed using "gnuplot.cfg"













GNUPLOT 4.1                                                      242


     [1m53.20.  Epson-180dpi[0m


     This driver supports a family of Epson printers and deriva-
     tives.

     [1mepson-180dpi [22mand [1mepson-60dpi [22mare drivers for Epson LQ-style
     24-pin printers with resolutions of 180 and 60 dots per inch,
     respectively.

     [1mepson-lx800 [22mis a generic 9-pin driver appropriate for printers
     like the Epson LX-800, the Star NL-10 and NX-1000, the PRO-
     PRINTER, and so forth.

     [1mnec-cp6 [22mis generic 24-pin driver that can be used for printers
     like the NEC CP6 and the Epson LQ-800.

     The [1mokidata [22mdriver supports the 9-pin OKIDATA 320/321 Standard
     printers.

     The [1mstarc [22mdriver is for the Star Color Printer.

     The [1mtandy-60dpi [22mdriver is for the Tandy DMP-130 series of
     9-pin, 60-dpi printers.

     Only [1mnec-cp6 [22mhas any options.

     Syntax:
           set terminal nec-cp6 {monochrome | colour | draft}

     which defaults to monochrome.

     With each of these drivers, a binary copy is required on a PC
     to print.  Do not use [1mprint[22m---use instead [1mcopy file /b lpt1:[22m.



     [1m53.21.  Excl[0m


     The [1mexcl [22mterminal driver supports Talaris printers such as the
     EXCL Laser printer and the 1590.  It has no options.



     [1m53.22.  Fig[0m


     The [1mfig [22mterminal device generates output in the Fig graphics
     language.

     Syntax:
           set terminal fig {monochrome | color}










GNUPLOT 4.1                                                      243


                            {landscape | portrait}
                            {small | big | size <xsize> <ysize>}
                            {metric | inches}
                            {pointsmax <max_points>}
                            {solid | dashed}
                            {fontsize <fsize>}
                            {textnormal | {textspecial texthidden
     textrigid}}
                            {{thickness|linewidth} <units>}
                            {depth <layer>}
                            {version <number>}

     [1mmonochrome [22mand [1mcolor [22mdetermine whether the picture is black-
     and-white or [1mcolor[22m.  [1msmall [22mand [1mbig [22mproduce a 5x3 or 8x5 inch
     graph in the default [1mlandscape [22mmode and 3x5 or 5x8 inches in
     [1mportrait [22mmode.  [1msize [22msets (overrides) the size of the drawing
     area to <xsize>*<ysize> in units of inches or centimeters
     depending on the [1minches [22mor [1mmetric [22msetting in effect.  The lat-
     ter settings is also used as default units for editing with
     "xfig".

     [1mpointsmax <max_points> [22msets the maximum number of points per
     polyline.

     [1msolid [22minhibits automatic usage of [1mdash[22med lines when solid
     linestyles are used up, which otherwise occurs.

     [1mfontsize [22msets the size of the text font to <fsize> points.
     [1mtextnormal [22mresets the text flags and selects postscript fonts,
     [1mtextspecial [22msets the text flags for LaTeX specials, [1mtexthidden[0m
     sets the hidden flag and [1mtextrigid [22mthe rigid flag.

     [1mdepth [22msets the default depth layer for all lines and text.  The
     default depth is 10 to leave room for adding material with
     "xfig" on top of the plot.

     [1mversion [22msets the format version of the generated fig output.
     Currently only versions 3.1 and 3.2 are supported.

     [1mthickness [22msets the default line thickness, which is 1 if not
     specified.  Overriding the thickness can be achieved by adding
     a multiple of 100 to the [1mlinetype [22mvalue for a [1mplot [22mcommand.  In
     a similar way the [1mdepth [22mof plot elements (with respect to the
     default depth) can be controlled by adding a multiple of 1000
     to <linetype>.  The depth is then <layer> + <linetype>/1000 and
     the thickness is (<linetype>%1000)/100 or, if that is zero, the
     default line thickness. [1mlinewidth [22mis a synonym for [1mthickness[22m.

     Additional point-plot symbols are also available with the [1mfig[0m
     driver. The symbols can be used through [1mpointtype [22mvalues % 100
     above 50, with different fill intensities controlled by <point-
     type> % 5 and outlines in black (for <pointtype> % 10 < 5) or
     in the current color.  Available symbols are










GNUPLOT 4.1                                                      244


             50 - 59:  circles
             60 - 69:  squares
             70 - 79:  diamonds
             80 - 89:  upwards triangles
             90 - 99:  downwards triangles
     The size of these symbols is linked to the font size.  The
     depth of symbols is by default one less than the depth for
     lines to achieve nice error bars.  If <pointtype> is above
     1000, the depth is <layer> + <pointtype>/1000-1.  If <point-
     type>%1000 is above 100, the fill color is (<point-
     type>%1000)/100-1.

     Available fill colors are (from 1 to 9): black, blue, green,
     cyan, red, magenta, yellow, white and dark blue (in monochrome
     mode: black for 1 to 6 and white for 7 to 9).

     See [1mplot with [22mfor details of <linetype> and <pointtype>.

     The [1mbig [22moption is a substitute for the [1mbfig [22mterminal in earlier
     versions, which is no longer supported.

     Examples:
           set terminal fig monochrome small pointsmax 1000  #
     defaults

           plot 'file.dat' with points linetype 102 pointtype 759
     would produce circles with a blue outline of width 1 and yellow
     fill color.

           plot 'file.dat' using 1:2:3 with err linetype 1 pointtype
     554
     would produce errorbars with black lines and circles filled
     red.  These circles are one layer above the lines (at depth 9
     by default).

     To plot the error bars on top of the circles use
           plot 'file.dat' using 1:2:3 with err linetype 1 pointtype
     2554



     [1m53.23.  Ggi[0m


     The [1mggi [22mdriver can run on different targets as X or svgalib.

     Syntax:
        set terminal ggi [acceleration <integer>] [[mode] {mode}]

     In X the window cannot be resized using window manager handles,
     but the mode can be given with the mode option, e.g.:
      - V1024x768
      - V800x600










GNUPLOT 4.1                                                      245


      - V640x480
      - V320x200
     Please refer to the ggi documentation for other modes. The
     'mode' keyword is optional. It is recommended to select the
     target by environment variables as explained in the libggi man-
     ual page. To get DGA on X, you should for example
        bash> export GGI_DISPLAY=DGA
        csh>  setenv GGI_DISPLAY DGA

     'acceleration' is only used for targets which report relative
     pointer motion events (e.g. DGA) and is a strictly positive
     integer multiplication factor for the relative distances.  The
     default for acceleration is 7.

     Examples:
        set term ggi acc 10
        set term ggi acc 1 mode V1024x768
        set term ggi V1024x768



     [1m53.24.  Gif[0m



     Syntax:
           set terminal gif
                            {tiny | small | medium | large | giant}
                            {{no}transparent} {{no}enhanced}
                            {font <face> {<pointsize>}}
                            {animate {delay <time>} {{no}optimize}}
                            {size <x>,<y>} {{no}crop}
                            {<color0> <color1> <color2> ...}

     GIF images are created using libgd, with optional support for
     TrueType fonts via libfreetype.

     GIF plots may be conveniently viewed by piping the output to
     the 'display' program from the ImageMagick package as follows:
                    set term gif
                    set output '| display gif:-'

     View the output from successive plot commands interactively by
     hitting <space> in the display window.  To save a particular
     one to disk, left click in the display window and choose [1msave[22m.

     Five basic fonts are supported directly by the gd library.
     These are [1mtiny [22m(5x8 pixels), [1msmall [22m(6x12 pixels), [1mmedium[22m, (7x13
     Bold), [1mlarge [22m(8x16) or [1mgiant [22m(9x15 pixels). These fonts cannot
     be scaled or rotated (pure horizontal or vertical text only).

     [1mtransparent [22minstructs the driver to generate transparent GIFs.
     The first color will be the transparent one. Default is










GNUPLOT 4.1                                                      246


     [1mnotransparent[22m.

     [1menhanced [22menables the enhanced text processing features, (sub-
     scripts, superscripts and mixed fonts). See [1menhanced [22mfor more
     information.  The full enhanced mode syntax is supported by the
     PNG/GIF driver itself, but some of these features are dependent
     on which version of the underlying libgd library is present,
     and which fonts are available.

     If your local gd library was built with support for TrueType
     and Adobe Type 1 fonts, they may be selected using the 'font
     <face> {<pointsize>}' option. <face> is either the full path-
     name to the font file, or a font face name that is assumed to
     be the first part of a filename in one of the directories
     listed in the GDFONTPATH environmental variable. That is, 'set
     term gif font "Face"' will look for a font file named either
     <somedirectory>/Face.ttf or <somedirectory>/Face.pfa. Both
     TrueType and Adobe Type 1 fonts are fully scalable and may be
     rotated through any angle.  If no font is specified, gnuplot
     checks the environmental variable GNUPLOT_DEFAULT_GDFONT to see
     if there is a preferred default font.

     The [1manimate [22moption is available only if your local gd library
     supports the creation of animated gifs. The default delay
     between display of successive images may be specified in units
     of 1/100 second (default 5).  The actual delay may vary depend-
     ing on the program used as a viewer.  An animation sequence is
     terminated by the next [1mset output [22mor [1mset term [22mcommand.  The
     [1moptimize [22moption has two effects on the animation.

     1) A single color map is used for the entire animation. This
     requires that all colors used in any frame of the animation are
     already defined in the first frame.

     2) If possible, only the portions of a frame that differ from
     the previous frame are stored in the animation file.  This
     space saving may not be possible if the animation uses trans-
     parency.

     Both of these optimizations are intended to produce a smaller
     output file, but the decrease in size is probably only signifi-
     cant for long animations or very small frame sizes.  The [1mnoop-[0m
     [1mtimize [22moption turns off both of the effects just described.
     Each frame is stored in its entirety along with a private color
     map.  Note that it is possible to post-process a non-optimized
     animation using external utilities, and this post-processing
     can yield a smaller file than gnuplot's internal optimization
     mode.  The default is [1mnooptimize[22m.

     The size <x,y> is given in pixels---it defaults to 640x480.
     The number of pixels can be also modified by scaling with the
     [1mset size [22mcommand.  [1mcrop [22mtrims blank space from the edges of the
     completed plot, resulting in a smaller final image size.










GNUPLOT 4.1                                                      247


     Default is [1mnocrop[22m.

     Each color must be of the form 'xrrggbb', where x is the lit-
     eral character 'x' and 'rrggbb' are the red, green and blue
     components in hex.  For example, 'x00ff00' is green.  The back-
     ground color is set first, then the border colors, then the X &
     Y axis colors, then the plotting colors.  The maximum number of
     colors that can be set is 256.

     Examples:
           set terminal gif medium size 640,480 \
                            xffffff x000000 x404040 \
                            xff0000 xffa500 x66cdaa xcdb5cd \
                            xadd8e6 x0000ff xdda0dd x9500d3    #
     defaults

     which uses white for the non-transparent background, black for
     borders, gray for the axes, and red, orange, medium aquamarine,
     thistle 3, light blue, blue, plum and dark violet for eight
     plotting colors.

           set terminal gif font 'arial' 14 size 800,600

     which searches for a TrueType font with face name 'arial' in
     the directory specified by the environment variable GDFONTPATH
     and 14pt font size.




     [1m53.25.  Gnugraph(GNU plotutils)[0m


     The [1mgnugraph [22mdriver produces device-independent output in the
     GNU plot graphics language.  The default size of the PostScript
     results generated by "plot2ps" is 5 x 3 inches; this can be
     increased up to about 8.25 x 8.25 by [1mset size[22m.

     Syntax:
           set terminal gnugraph {"<fontname>"} {<fontsize>}
                                 {type <pt>} {size "<size>"}

     which defaults to 10-point "Courier".

     For [1mtype[22m, the following options are accepted: [1mX[22m, [1mpnm[22m, [1mgif[22m, [1mai[22m,
     [1mps[22m, [1mcgm[22m, [1mfig[22m, [1mpcl5[22m, [1mhpgl[22m, [1mtek[22m, and [1mmeta [22m(default). The [1msize[0m
     option (default is a4) is passed straight through to plotutils,
     it's the user's responsibility to provide correct values.
     Details can be found in the plotutils documentation.

     Examples:
           set terminal gnugraph type hpgl size "a4"
           set terminal gnugraph size










GNUPLOT 4.1                                                      248


     "a4,xoffset=-5mm,yoffset=2.0cm" type pnm

     There is a non-GNU version of the [1mgnugraph [22mdriver which cannot
     be compiled unless this version is left out.



     [1m53.26.  Gpic[0m


     The [1mgpic [22mterminal driver generates GPIC graphs in the Free
     Software Foundations's "groff" package.  The default size is 5
     x 3 inches.  The only option is the origin, which defaults to
     (0,0).

     Syntax:
           set terminal gpic {<x> <y>}

     where [1mx [22mand [1my [22mare in inches.

     A simple graph can be formatted using

           groff -p -mpic -Tps file.pic > file.ps.

     The output from pic can be pipe-lined into eqn, so it is possi-
     ble to put complex functions in a graph with the [1mset label [22mand
     [1mset {x/y}label [22mcommands.  For instance,

           set ylab '@space 0 int from 0 to x alpha ( t ) roman d
     t@'

     will label the y axis with a nice integral if formatted with
     the command:

           gpic filename.pic | geqn -d@@ -Tps | groff -m[macro-pack-
     age] -Tps
               > filename.ps

     Figures made this way can be scaled to fit into a document.
     The pic language is easy to understand, so the graphs can be
     edited by hand if need be.  All co-ordinates in the pic-file
     produced by [1mgnuplot [22mare given as x+gnuplotx and y+gnuploty.  By
     default x and y are given the value 0.  If this line is removed
     with an editor in a number of files, one can put several graphs
     in one figure like this (default size is 5.0x3.0 inches):

           .PS 8.0
           x=0;y=3
           copy "figa.pic"
           x=5;y=3
           copy "figb.pic"
           x=0;y=0
           copy "figc.pic"










GNUPLOT 4.1                                                      249


           x=5;y=0
           copy "figd.pic"
           .PE

     This will produce an 8-inch-wide figure with four graphs in two
     rows on top of each other.

     One can also achieve the same thing by the command

           set terminal gpic x y

     for example, using

           .PS 6.0
           copy "trig.pic"
           .PE



     [1m53.27.  Gpr[0m


     The [1mgpr [22mterminal driver supports the Apollo Graphics Primitive
     Resource for a fixed-size window.  It has no options.

     If a variable window size is desired, use the [1mapollo [22mterminal
     instead.



     [1m53.28.  Grass[0m


     The [1mgrass [22mterminal driver gives [1mgnuplot [22mcapabilities to users
     of the GRASS geographic information system.  Contact grassp-
     list@moon.cecer.army.mil for more information.  Pages are writ-
     ten to the current frame of the GRASS Graphics Window.  There
     are no options.



     [1m53.29.  Hercules[0m


     These drivers supports PC monitors with autodetected graphics
     boards.  They can be used only when compiled with Zortech
     C/C++.  None have options.
















GNUPLOT 4.1                                                      250


     [1m53.30.  Hp2623a[0m


     The [1mhp2623a [22mterminal driver supports the Hewlett Packard
     HP2623A.  It has no options.



     [1m53.31.  Hp2648[0m


     The [1mhp2648 [22mterminal driver supports the Hewlett Packard HP2647
     and HP2648.  It has no options.



     [1m53.32.  Hp500c[0m


     The [1mhp500c [22mterminal driver supports the Hewlett Packard HP
     DeskJet 500c.  It has options for resolution and compression.

     Syntax:
           set terminal hp500c {<res>} {<comp>}

     where [1mres [22mcan be 75, 100, 150 or 300 dots per inch and [1mcomp [22mcan
     be "rle", or "tiff".  Any other inputs are replaced by the
     defaults, which are 75 dpi and no compression.  Rasterization
     at the higher resolutions may require a large amount of memory.



     [1m53.33.  Hpgl[0m


     The [1mhpgl [22mdriver produces HPGL output for devices like the
     HP7475A plotter.  There are two options which can be set: the
     number of pens and [1meject[22m, which tells the plotter to eject a
     page when done.  The default is to use 6 pens and not to eject
     the page when done.

     The international character sets ISO-8859-1 and CP850 are rec-
     ognized via [1mset encoding iso_8859_1 [22mor [1mset encoding cp850 [22m(see
     [1mset encoding [22mfor details).

     Syntax:
           set terminal hpgl {<number_of_pens>} {eject}

     The selection

           set terminal hpgl 8 eject

     is equivalent to the previous [1mhp7550 [22mterminal, and the










GNUPLOT 4.1                                                      251


     selection

           set terminal hpgl 4

     is equivalent to the previous [1mhp7580b [22mterminal.

     The [1mpcl5 [22mdriver supports plotters such as the Hewlett-Packard
     Designjet 750C, the Hewlett-Packard Laserjet III, and the
     Hewlett-Packard Laserjet IV.  It actually uses HPGL-2, but
     there is a name conflict among the terminal devices.  It has
     several options which must be specified in the order indicated
     below:

     Syntax:
           set terminal pcl5 {mode <mode>} {<plotsize>}
               {{color {<number_of_pens>}} | monochrome} {solid |
     dashed}
               {font <font>} {size <fontsize>} {pspoints | nops-
     points}

     <mode> is [1mlandscape [22mor [1mportrait[22m. <plotsize> is the physical
     plotting size of the plot, which is one of the following: [1mlet-[0m
     [1mter [22mfor standard (8 1/2" X 11") displays, [1mlegal [22mfor (8 1/2" X
     14") displays, [1mnoextended [22mfor (36" X 48") displays (a letter
     size ratio) or, [1mextended [22mfor (36" X 55") displays (almost a
     legal size ratio).  [1mcolor [22mis for multi-pen (i.e. color) plots,
     and <number_of_pens> is the number of pens (i.e. colors) used
     in color plots. [1mmonochrome [22mis for one (e.g. black) pen plots.
     [1msolid [22mdraws all lines as solid lines, or [1mdashed [22mwill draw lines
     with different dashed and dotted line patterns.  <font> is
     [1mstick[22m, [1munivers[22m, [1mcg_times[22m, [1mzapf_dingbats[22m, [1mantique_olive[22m, [1marial[22m,
     [1mcourier[22m, [1mgaramond_antigua[22m, [1mletter_gothic[22m, [1mcg_omega[22m, [1malbertus[22m,
     [1mtimes_new_roman[22m, [1mclarendon[22m, [1mcoronet[22m, [1mmarigold[22m, [1mtruetype_sym-[0m
     [1mbols[22m, or [1mwingdings[22m. <fontsize> is the font size in points.  The
     point type selection can be the standard default set by speci-
     fying [1mnopspoints[22m, or the same set of point types found in the
     postscript terminal by specifying [1mpspoints[22m.

     Note that built-in support of some of these options is printer
     device dependent. For instance, all the fonts are supposedly
     supported by the HP Laserjet IV, but only a few (e.g. univers,
     stick) may be supported by the HP Laserjet III and the Design-
     jet 750C. Also, color obviously won't work on the the laserjets
     since they are monochrome devices.

     Defaults: landscape, noextended, color (6 pens), solid,
     univers, 12 point,
               and nopspoints.

     With [1mpcl5 [22minternational characters are handled by the printer;
     you just put the appropriate 8-bit character codes into the
     text strings.  You don't need to bother with [1mset encoding[22m.











GNUPLOT 4.1                                                      252


     HPGL graphics can be imported by many software packages.



     [1m53.34.  Hpljii[0m


     The [1mhpljii [22mterminal driver supports the HP Laserjet Series II
     printer.  The [1mhpdj [22mdriver supports the HP DeskJet 500 printer.
     These drivers allow a choice of resolutions.

     Syntax:
           set terminal hpljii | hpdj {<res>}

     where [1mres [22mmay be 75, 100, 150 or 300 dots per inch; the default
     is 75.  Rasterization at the higher resolutions may require a
     large amount of memory.

     The [1mhp500c [22mterminal is similar to [1mhpdj[22m; [1mhp500c [22madditionally
     supports color and compression.



     [1m53.35.  Hppj[0m


     The [1mhppj [22mterminal driver supports the HP PaintJet and HP3630
     printers.  The only option is the choice of font.

     Syntax:
           set terminal hppj {FNT5X9 | FNT9X17 | FNT13X25}

     with the middle-sized font (FNT9X17) being the default.



     [1m53.36.  Imagen[0m


     The [1mimagen [22mterminal driver supports Imagen laser printers.  It
     is capable of placing multiple graphs on a single page.

     Syntax:
           set terminal imagen {<fontsize>} {portrait | landscape}
                               {[<horiz>,<vert>]}

     where [1mfontsize [22mdefaults to 12 points and the layout defaults to
     [1mlandscape[22m.  [1m<horiz> [22mand [1m<vert> [22mare the number of graphs in the
     horizontal and vertical directions; these default to unity.

     Example:
           set terminal imagen portrait [2,3]











GNUPLOT 4.1                                                      253


     puts six graphs on the page in three rows of two in portrait
     orientation.



     [1m53.37.  Iris4d[0m


     The [1miris4d [22mterminal driver supports Silicon Graphics IRIS 4D
     computers.  Its only option is 8- or 24-bit color depth.  The
     default is 8.

     Syntax:
           set terminal iris4d {8 | 24}

     The color depth is not really a choice -- the value appropriate
     for the hardware should be selected.

     When using 24-bit mode, the colors can be directly specified
     via the file .gnuplot_iris4d that is searched in the current
     directory and then in the home directory specified by the HOME
     environment variable.  This file holds RGB values for the back-
     ground, border, labels and nine plotting colors, in that order.
     For example, here is a file containing the default colors:

           85   85   85     Background   (dark gray)
           0    0    0      Boundary     (black)
           170  0    170    Labeling     (magenta)
           85   255  255    Plot Color 1 (light cyan)
           170  0    0      Plot Color 2 (red)
           0    170  0      Plot Color 3 (green)
           255  85   255    Plot Color 4 (light magenta)
           255  255  85     Plot Color 5 (yellow)
           255  85   85     Plot Color 6 (light red)
           85   255  85     Plot Color 7 (light green)
           0    170  170    Plot Color 8 (cyan)
           170  170  0      Plot Color 9 (brown)

     This file must have exactly 12 lines of RGB triples.  No empty
     lines are allowed, and anything after the third number on a
     line is ignored.



     [1m53.38.  Jpeg[0m



     Syntax:
           set terminal jpeg
                            {{no}interlace}
                            {tiny | small | medium | large | giant}
                            {font <face> {<pointsize>}}










GNUPLOT 4.1                                                      254


                            {size <x>,<y>} {{no}crop}
                            {{no}enhanced}
                            {<color0> <color1> <color2> ...}

     JPEG images are created using libgd, with optional support for
     TrueType fonts via libfreetype.

     The [1minterlace [22moption creates a progressive JPEG image.  Default
     is [1mnointerlace[22m.

     Five basic fonts are supported directly by the gd library.
     These are [1mtiny [22m(5x8 pixels), [1msmall [22m(6x12 pixels), [1mmedium[22m, (7x13
     Bold), [1mlarge [22m(8x16) or [1mgiant [22m(9x15 pixels). These fonts cannot
     be scaled or rotated (pure horizontal or vertical text only).

     If gnuplot was built with support for TrueType (*.ttf) or Adobe
     Type 1 (*.pfa) fonts, they may be selected using the 'font
     <face> {<pointsize>}' option. <face> is either the full path-
     name to the font file, or a font face name that is assumed to
     be the first part of a filename in one of the directories
     listed in the GDFONTPATH environmental variable. That is, 'set
     term jpeg font "Face"' will look for a font file named either
     <somedirectory>/Face.ttf or <somedirectory>/Face.pfa. Both
     TrueType and Adobe Type 1 fonts are fully scalable and may be
     rotated through any angle.  If no font is specified, gnuplot
     checks the environmental variable GNUPLOT_DEFAULT_GDFONT to see
     if there is a preferred default font.

     [1menhanced [22menables the enhanced text processing features, (sub-
     scripts, superscripts and mixed fonts). See [1menhanced [22mfor more
     information.  The full enhanced mode syntax is supported by the
     PNG/JPEG driver itself, but some of these features are depen-
     dent on which version of the underlying libgd library is
     present, and which fonts are available.

     The size <x,y> is given in pixels---it defaults to 640x480.
     The number of pixels can be also modified by scaling with the
     [1mset size [22mcommand.  [1mcrop [22mtrims blank space from the edges of the
     completed plot, resulting in a smaller final image size.
     Default is [1mnocrop[22m.

     Each color must be of the form 'xrrggbb', where x is the lit-
     eral character 'x' and 'rrggbb' are the red, green and blue
     components in hex.  For example, 'x00ff00' is green.  The back-
     ground color is set first, then the border colors, then the X &
     Y axis colors, then the plotting colors.  The maximum number of
     colors that can be set is 256.

     Examples:
           set terminal jpeg medium size 640,480 \
                            xffffff x000000 x404040 \
                            xff0000 xffa500 x66cdaa xcdb5cd \
                            xadd8e6 x0000ff xdda0dd x9500d3    #










GNUPLOT 4.1                                                      255


     defaults

     which uses white for the non-transparent background, black for
     borders, gray for the axes, and red, orange, medium aquamarine,
     thistle 3, light blue, blue, plum and dark violet for eight
     plotting colors.

           set terminal jpeg large font arial size 800,600

     which searches for a TrueType font with face name 'arial' in
     the directory specified by the environment variable GDFONTPATH
     and large (14pt) font size.




     [1m53.39.  Kyo[0m


     The [1mkyo [22mand [1mprescribe [22mterminal drivers support the Kyocera
     laser printer.  The only difference between the two is that [1mkyo[0m
     uses "Helvetica" whereas [1mprescribe [22muses "Courier".  There are
     no options.



     [1m53.40.  Latex[0m


     The [1mlatex [22mand [1memtex [22mdrivers allow two options.

     Syntax:
           set terminal latex | emtex {courier | roman | default}
     {<fontsize>}

     [1mfontsize [22mmay be any size you specify.  The default is for the
     plot to inherit its font setting from the embedding document.

     Unless your driver is capable of building fonts at any size
     (e.g. dvips), stick to the standard 10, 11 and 12 point sizes.

     METAFONT users beware: METAFONT does not like odd sizes.

     All drivers for LaTeX offer a special way of controlling text
     positioning: If any text string begins with '{', you also need
     to include a '}' at the end of the text, and the whole text
     will be centered both horizontally and vertically.  If the text
     string begins with '[', you need to follow this with a position
     specification (up to two out of t,b,l,r), ']{', the text
     itself, and finally '}'.  The text itself may be anything LaTeX
     can typeset as an LR-box.  '\rule{}{}'s may help for best posi-
     tioning.











GNUPLOT 4.1                                                      256


     Points, among other things, are drawn using the LaTeX commands
     "\Diamond" and "\Box".  These commands no longer belong to the
     LaTeX2e core; they are included in the latexsym package, which
     is part of the base distribution and thus part of any LaTeX
     implementation.  Please do not forget to use this package.

     Examples: About label positioning: Use gnuplot defaults (mostly
     sensible, but sometimes not really best):
            set title '\LaTeX\ -- $ \gamma $'
     Force centering both horizontally and vertically:
            set label '{\LaTeX\ -- $ \gamma $}' at 0,0
     Specify own positioning (top here):
            set xlabel '[t]{\LaTeX\ -- $ \gamma $}'
     The other label -- account for long ticlabels:
            set ylabel '[r]{\LaTeX\ -- $ \gamma $\rule{7mm}{0pt}}'



     [1m53.41.  Linux[0m


     The [1mlinux [22mdriver has no additional options to specify.  It
     looks at the environment variable GSVGAMODE for the default
     mode; if not set, it uses 1024x768x256 as default mode or, if
     that is not possible, 640x480x16 (standard VGA).



     [1m53.42.  Macintosh[0m


     Several options may be set in the 'macintosh' driver.

     Syntax:
          set terminal macintosh {singlewin | multiwin} {vertical |
     novertical}
                                 {size <width>, <height> | default}

     'singlewin' limits the output to a single window and is useful
     for animations.  'multiwin' allows multiple windows.  'verti-
     cal' is only valid under the gx option. With this option,
     rotated text
         be drawn vertically. novertical turns this option off.
      size <width>, <height> overrides the graph size set in the
     preferences
         dialog until it is cleared with either 'set term mac size
     default'
         or 'set term mac default'.

      'set term mac size default' sets the window size settings to
     those set in
         the preferences dialog.











GNUPLOT 4.1                                                      257


      'set term mac default' sets all options to their default val-
     ues.
         Default values: nogx, multiwin, novertical.

      If you generate graphs under the multiwin option and then
     switch to singlewin,
      the next plot command will cause one more window to be cre-
     ated. This new
      window will be reused as long as singlewin is in effect. If
     you switch back
      to multiwin, generate some graphs, and then switch to sin-
     glewin again, the
      orginal 'singlewin' window will be resused if it is still
     open. Otherwise
      a new 'singlewin' window will be created. The 'singlewin' win-
     dow is not numbered.



     [1m53.43.  Mf[0m


     The [1mmf [22mterminal driver creates an input file to the METAFONT
     program.  Thus a figure may be used in the TeX document in the
     same way as is a character.

     To use a picture in a document, the METAFONT program must be
     run with the output file from [1mgnuplot [22mas input.  Thus, the user
     needs a basic knowledge of the font creating process and the
     procedure for including a new font in a document.  However, if
     the METAFONT program is set up properly at the local site, an
     unexperienced user could perform the operation without much
     trouble.

     The text support is based on a METAFONT character set.  Cur-
     rently the Computer Modern Roman font set is input, but the
     user is in principal free to choose whatever fonts he or she
     needs.  The METAFONT source files for the chosen font must be
     available.  Each character is stored in a separate picture
     variable in METAFONT.  These variables may be manipulated
     (rotated, scaled etc.) when characters are needed.  The draw-
     back is the interpretation time in the METAFONT program.  On
     some machines (i.e. PC) the limited amount of memory available
     may also cause problems if too many pictures are stored.

     The [1mmf [22mterminal has no options.

















GNUPLOT 4.1                                                      258


          [1m53.43.1.  METAFONT Instructions[0m



          - Set your terminal to METAFONT:
            set terminal mf
          - Select an output-file, e.g.:
            set output "myfigures.mf"
          - Create your pictures. Each picture will generate a sepa-
          rate character. Its default size will be 5*3 inches. You
          can change the size by saying [1mset size 0.5,0.5 [22mor whatever
          fraction of the default size you want to have.

          - Quit [1mgnuplot[22m.

          - Generate a TFM and GF file by running METAFONT on the
          output of [1mgnuplot[22m.  Since the picture is quite large (5*3
          in), you will have to use a version of METAFONT that has a
          value of at least 150000 for memmax.  On Unix systems
          these are conventionally installed under the name bigmf.
          For the following assume that the command virmf stands for
          a big version of METAFONT.  For example:

          - Invoke METAFONT:
              virmf '&plain'
          - Select the output device: At the METAFONT prompt ('*')
          type:
              \mode:=CanonCX;     % or whatever printer you use
          - Optionally select a magnification:
              mag:=1;             % or whatever you wish
          - Input the [1mgnuplot[22m-file:
              input myfigures.mf
          On a typical Unix machine there will usually be a script
          called "mf" that executes virmf '&plain', so you probably
          can substitute mf for virmf &plain.  This will generate
          two files: mfput.tfm and mfput.$$$gf (where $$$ indicates
          the resolution of your device).  The above can be conve-
          niently achieved by typing everything on the command line,
          e.g.: virmf '&plain' '\mode:=CanonCX; mag:=1; input myfig-
          ures.mf' In this case the output files will be named
          myfigures.tfm and myfigures.300gf.

          - Generate a PK file from the GF file using gftopk:
            gftopk myfigures.300gf myfigures.300pk
          The name of the output file for gftopk depends on the DVI
          driver you use.  Ask your local TeX administrator about
          the naming conventions.  Next, either install the TFM and
          PK files in the appropriate directories, or set your envi-
          ronment variables properly.  Usually this involves setting
          TEXFONTS to include the current directory and doing the
          same thing for the environment variable that your DVI
          driver uses (no standard name here...).  This step is nec-
          essary so that TeX will find the font metric file and your










GNUPLOT 4.1                                                      259


          DVI driver will find the PK file.

          - To include your pictures in your document you have to
          tell TeX the font:
            \font\gnufigs=myfigures
          Each picture you made is stored in a single character.
          The first picture is character 0, the second is character
          1, and so on...  After doing the above step, you can use
          the pictures just like any other characters.  Therefore,
          to place pictures 1 and 2 centered in your document, all
          you have to do is:
            \centerline{\gnufigs\char0}
            \centerline{\gnufigs\char1}
          in plain TeX.  For LaTeX you can, of course, use the pic-
          ture environment and place the picture wherever you wish
          by using the \makebox and \put macros.

          This conversion saves you a lot of time once you have gen-
          erated the font; TeX handles the pictures as characters
          and uses minimal time to place them, and the documents you
          make change more often than the pictures do.  It also
          saves a lot of TeX memory.  One last advantage of using
          the METAFONT driver is that the DVI file really remains
          device independent, because no \special commands are used
          as in the eepic and tpic drivers.



     [1m53.44.  Mgr[0m


     The [1mmgr [22mterminal driver supports the Mgr Window system.  It has
     no options.



     [1m53.45.  Mif[0m


     The [1mmif [22mterminal driver produces Frame Maker MIF format version
     3.00.  It plots in MIF Frames with the size 15*10 cm, and plot
     primitives with the same pen will be grouped in the same MIF
     group.  Plot primitives in a [1mgnuplot [22mpage will be plotted in a
     MIF Frame, and several MIF Frames are collected in one large
     MIF Frame.  The MIF font used for text is "Times".

     Several options may be set in the MIF 3.00 driver.

     Syntax:
           set terminal mif {color | colour | monochrome} {polyline
     | vectors}
                            {help | ?}











GNUPLOT 4.1                                                      260


     [1mcolour [22mplots lines with line types >= 0 in colour (MIF sep.
     2--7) and [1mmonochrome [22mplots all line types in black (MIF sep.
     0).  [1mpolyline [22mplots curves as continuous curves and [1mvectors[0m
     plots curves as collections of vectors.  [1mhelp [22mand [1m? [22mprint
     online help on standard error output---both print a short
     description of the usage; [1mhelp [22malso lists the options.

     Examples:
           set term mif colour polylines    # defaults
           set term mif                     # defaults
           set term mif vectors
           set term mif help



     [1m53.46.  Mp[0m



     The [1mmp [22mdriver produces output intended to be input to the Meta-
     post program.  Running Metapost on the file creates EPS files
     containing the plots. By default, Metapost passes all text
     through TeX.  This has the advantage of allowing essentially
     any TeX symbols in titles and labels.

     Syntax:
        set term mp {color | colour | monochrome}
                    {solid | dashed}
                    {notex | tex | latex}
                    {magnification <magsize>}
                    {psnfss | psnfss-version7 | nopsnfss}
                    {prologues <value>}
                    {a4paper}
                    {amstex}
                    {"<fontname>"} {<fontsize>}

     The option [1mcolor [22mcauses lines to be drawn in color (on a
     printer or display that supports it), [1mmonochrome [22m(or nothing)
     selects black lines.  The option [1msolid [22mdraws solid lines, while
     [1mdashed [22m(or nothing) selects lines with different patterns of
     dashes.  If [1msolid [22mis selected but [1mcolor [22mis not, nearly all
     lines will be identical.  This may occasionally be useful, so
     it is allowed.

     The option [1mnotex [22mbypasses TeX entirely, therefore no TeX code
     can be used in labels under this option.  This is intended for
     use on old plot files or files that make frequent use of common
     characters like [1m$ [22mand [1m% [22mthat require special handling in TeX.

     The option [1mtex [22msets the terminal to output its text for TeX to
     process.

     The option [1mlatex [22msets the terminal to output its text for










GNUPLOT 4.1                                                      261


     processing by LaTeX. This allows things like \frac for frac-
     tions which LaTeX knows about but TeX does not.  Note that you
     must set the environment variable TEX to the name of your LaTeX
     executable (normally latex) if you use this option or use [1mmpost[0m
     [1m--tex=<name of LaTeX executable> ...[22m. Otherwise metapost will
     try and use TeX to process the text and it won't work.

     Changing font sizes in TeX has no effect on the size of mathe-
     matics, and there is no foolproof way to make such a change,
     except by globally  setting a magnification factor. This is the
     purpose of the [1mmagnification [22moption. It must be followed by a
     scaling factor. All text (NOT the graphs) will be scaled by
     this factor. Use this if you have math that you want at some
     size other than the default 10pt. Unfortunately, all math will
     be the same size, but see the discussion below on editing the
     MP output. [1mmag [22mwill also work under [1mnotex [22mbut there seems no
     point in using it as the font size option (below) works as
     well.

     The option [1mpsnfss [22muses postscript fonts in combination with
     LaTeX. Since this option only makes sense, if LaTeX is being
     used, the [1mlatex [22moption is selected automatically. This option
     includes the following packages for LaTeX: inputenc(latin1),
     fontenc(T1), mathptmx, helvet(scaled=09.2), courier, latexsym
     and textcomp.

     The option [1mpsnfss-version7 [22muses also postscript fonts in LaTeX
     (option [1mlatex [22mis also automatically selected), but uses the
     following packages with LaTeX: inputenc(latin1), fontenc(T1),
     times, mathptmx, helvet and courier.

     The option [1mnopsnfss [22mis the default and uses the standard font
     (cmr10 if not otherwise specified).

     The option [1mprologues [22mtakes a value as an additional argument
     and adds the line [1mprologues:=<value> [22mto the metapost file. If a
     value of [1m2 [22mis specified metapost uses postscript fonts to gen-
     erate the eps-file, so that the result can be viewed using e.g.
     ghostscript. Normally the output of metapost uses TeX fonts and
     therefore has to be included in a (La)TeX file before you can
     look at it.

     The option [1mnoprologues [22mis the default. No additional line spec-
     ifying the prologue will be added.

     The option [1ma4paper [22madds a [1m[a4paper] [22mto the documentclass. Nor-
     mally letter paper is used (default). Since this option is only
     used in case of LaTeX, the [1mlatex [22moption is selected automati-
     cally.

     The option [1mamstex [22mautomatically selects the [1mlatex [22moption and
     includes the following LaTeX packages: amsfonts, ams-
     math(intlimits). By default these packages are not included.










GNUPLOT 4.1                                                      262


     A name in quotes selects the font that will be used when no
     explicit font is given in a [1mset label [22mor [1mset title[22m.  A name
     recognized by TeX (a TFM file exists) must be used.  The
     default is "cmr10" unless [1mnotex [22mis selected, then it is
     "pcrr8r" (Courier).  Even under [1mnotex[22m, a TFM file is needed by
     Metapost. The file [1mpcrr8r.tfm [22mis the name given to Courier in
     LaTeX's psnfss package.  If you change the font from the [1mnotex[0m
     default, choose a font that matches the ASCII encoding at least
     in the range 32-126.  [1mcmtt10 [22malmost works, but it has a non-
     blank character in position 32 (space).

     The size can be any number between 5.0 and 99.99.  If it is
     omitted, 10.0 is used.  It is advisable to use [1mmagstep [22msizes:
     10 times an integer or half-integer power of 1.2, rounded to
     two decimals, because those are the most available sizes of
     fonts in TeX systems.

     All the options are optional.  If font information is given, it
     must be at the end, with size (if present) last.  The size is
     needed to select a size for the font, even if the font name
     includes size information.  For example, [1mset term mp "cmtt12"[0m
     selects cmtt12 shrunk to the default size 10.  This is probably
     not what you want or you would have used cmtt10.

     The following common ascii characters need special treatment in
     TeX:
        $, &, #, %, _;  |, <, >;  ^, ~,  \, {, and }
     The five characters $, #, &, _, and % can simply be escaped,
     e.g., [1m\$[22m.  The three characters <, >, and | can be wrapped in
     math mode, e.g., [1m$<$[22m.  The remainder require some TeX work-
     arounds.  Any good book on TeX will give some guidance.

     If you type your labels inside double quotes, backslashes in
     TeX code need to be escaped (doubled). Using single quotes will
     avoid having to do this, but then you cannot use [1m\n [22mfor line
     breaks.  As of this writing, version 3.7 of gnuplot processes
     titles given in a [1mplot [22mcommand differently than in other
     places, and backslashes in TeX commands need to be doubled
     regardless of the style of quotes.

     Metapost pictures are typically used in TeX documents.  Meta-
     post deals with fonts pretty much the same way TeX does, which
     is different from most other document preparation programs.  If
     the picture is included in a LaTeX document using the graphics
     package, or in a plainTeX document via epsf.tex, and then con-
     verted to PostScript with dvips (or other dvi-to-ps converter),
     the text in the plot will usually be handled correctly.  How-
     ever, the text may not appear if you send the Metapost output
     as-is to a PostScript interpreter.














GNUPLOT 4.1                                                      263


          [1m53.46.1.  Metapost Instructions[0m



          - Set your terminal to Metapost, e.g.:
             set terminal mp mono "cmtt12" 12

          - Select an output-file, e.g.:
             set output "figure.mp"

          - Create your pictures.  Each plot (or multiplot group)
          will generate a separate Metapost beginfig...endfig group.
          Its default size will be 5 by 3 inches.  You can change
          the size by saying [1mset size 0.5,0.5 [22mor whatever fraction
          of the default size you want to have.

          - Quit gnuplot.

          - Generate EPS files by running Metapost on the output of
          gnuplot:
             mpost figure.mp  OR  mp figure.mp
          The name of the Metapost program depends on the system,
          typically [1mmpost [22mfor a Unix machine and [1mmp [22mon many others.
          Metapost will generate one EPS file for each picture.

          - To include your pictures in your document you can use
          the graphics package in LaTeX or epsf.tex in plainTeX:
             \usepackage{graphics} % LaTeX
             \input epsf.tex       % plainTeX
          If you use a driver other than dvips for converting TeX
          DVI output to PS, you may need to add the following line
          in your LaTeX document:
             \DeclareGraphicsRule{*}{eps}{*}{}
          Each picture you made is in a separate file.  The first
          picture is in, e.g., figure.0, the second in figure.1, and
          so on....  To place the third picture in your document,
          for example, all you have to do is:
             \includegraphics{figure.2} % LaTeX
             \epsfbox{figure.2}         % plainTeX

          The advantage, if any, of the mp terminal over a
          postscript terminal is editable output.  Considerable
          effort went into making this output as clean as possible.
          For those knowledgeable in the Metapost language, the
          default line types and colors can be changed by editing
          the arrays [1mlt[] [22mand [1mcol[][22m.  The choice of solid vs dashed
          lines, and color vs black lines can be change by changing
          the values assigned to the booleans [1mdashedlines [22mand [1mcolor-[0m
          [1mlines[22m.  If the default [1mtex [22moption was in effect, global
          changes to the text of labels can be achieved by editing
          the [1mvebatimtex...etex [22mblock.  In particular, a LaTeX
          preamble can be added if desired, and then LaTeX's built-
          in size changing commands can be used for maximum










GNUPLOT 4.1                                                      264


          flexibility. Be sure to set the appropriate MP configura-
          tion variable to force Metapost to run LaTeX instead of
          plainTeX.



     [1m53.47.  Mtos[0m


     The [1mmtos [22mterminal has no options.  It sends data via a pipe to
     an external program called GPCLIENT.  It runs under MULTITOS,
     Magic 3.x, MagicMAC. and MiNT.  If you cannot find GPCLIENT,
     than mail to dirk@lstm.uni-erlangen.de.



     [1m53.48.  Next[0m


     Several options may be set in the next driver.

     Syntax:
           set terminal next {<mode>} {<type> } {<color>} {<dashed>}
                      {"<fontname>"} {<fontsize>} title {"<newti-
     tle>"}

     where <mode> is  [1mdefault[22m, which sets all options to their
     defaults; <type> is either [1mnew [22mor [1mold[22m, where [1mold [22minvokes the
     old single window; <color> is either [1mcolor [22mor [1mmonochrome[22m;
     <dashed> is either [1msolid [22mor [1mdashed[22m; "<fontname>" is the name of
     a valid PostScript font; <fontsize> is the size of the font in
     PostScript points; and <title> is the title for the GnuTerm
     window.  Defaults are  [1mnew[22m, [1mmonochrome[22m, [1mdashed[22m, "Helvetica",
     14pt.

     Examples:
           set term next default
           set term next 22
           set term next color "Times-Roman" 14
           set term next color "Helvetica" 12 title "MyPlot"
           set term next old

     Pointsizes may be changed with [1mset linestyle[22m.



     [1m53.49.  Openstep (next)[0m


     Several options may be set in the openstep (next) driver.

     Syntax:
           set terminal openstep {<mode>} {<type> } {<color>}










GNUPLOT 4.1                                                      265


     {<dashed>}
                      {"<fontname>"} {<fontsize>} title {"<newti-
     tle>"}

     where <mode> is  [1mdefault[22m, which sets all options to their
     defaults; <type> is either [1mnew [22mor [1mold[22m, where [1mold [22minvokes the
     old single window; <color> is either [1mcolor [22mor [1mmonochrome[22m;
     <dashed> is either [1msolid [22mor [1mdashed[22m; "<fontname>" is the name of
     a valid PostScript font; <fontsize> is the size of the font in
     PostScript points; and <title> is the title for the GnuTerm
     window.  Defaults are  [1mnew[22m, [1mmonochrome[22m, [1mdashed[22m, "Helvetica",
     14pt.

     Examples:
           set term openstep default
           set term openstep 22
           set term openstep color "Times-Roman" 14
           set term openstep color "Helvetica" 12 title "MyPlot"
           set term openstep old

     Pointsizes may be changed with [1mset linestyle[22m.



     [1m53.50.  Pbm[0m


     Several options may be set in the [1mpbm [22mterminal---the driver for
     PBMplus.

     Syntax:
           set terminal pbm {<fontsize>} {<mode>} {size <x>,<y>}

     where <fontsize> is [1msmall[22m, [1mmedium[22m, or [1mlarge [22mand <mode> is
     [1mmonochrome[22m, [1mgray [22mor [1mcolor[22m.  The default plot size is 640 pixels
     wide and 480 pixels high.

     The output of the [1mpbm [22mdriver depends upon <mode>: [1mmonochrome[0m
     produces a portable bitmap (one bit per pixel), [1mgray [22ma portable
     graymap (three bits per pixel) and [1mcolor [22ma portable pixmap
     (color, four bits per pixel).

     The output of this driver can be used with various image con-
     version and manipulation utilities provided by NETPBM.  Based
     on Jef Poskanzer's PBMPLUS package, NETPBM provides programs to
     convert the above PBM formats to GIF, TIFF, MacPaint, Macintosh
     PICT, PCX, X11 bitmap and many others.  Complete information is
     available at http://netpbm.sourceforge.net/.

     Examples:
           set terminal pbm small monochrome                #
     defaults
           set terminal pbm color medium size 800,600










GNUPLOT 4.1                                                      266


           set output '| pnmrotate 45 | pnmtopng > tilted.png'  #
     uses NETPBM



     [1m53.51.  Pdf[0m


     This terminal produces files in the Adobe Portable Document
     Format (PDF), useable for printing or display with tools like
     Acrobat Reader

     Syntax:
           set terminal pdf {monochrome|color|colour}
                            {{no}enhanced}
                            {fname "<font>"} {fsize <fontsize>}
                            {font "<fontname>{,<fontsize>}"}
                            {linewidth <lw>} {rounded|butt}
                            {solid|dashed} {dl <dashlength>}}
                            {size <XX>{unit},<YY>{unit}}

     The default is to use a different color for each line type.
     Selecting [1mmonochome [22mwill use black for all linetypes, in which
     case you probably want to select [1mdashed [22mto distinguish line
     types. Even in in mono mode you can still use explicit colors
     for filled areas or linestyles.

     where <font> is the name of the default font to use (default
     Helvetica) and <fontsize> is the font size (in points, default
     12).  For help on which fonts are available or how to install
     new ones, please see the documentation for your local installa-
     tion of pdflib.

     The [1menhanced [22moption enables enhanced text processing features
     (subscripts, superscripts and mixed fonts). See [1menhanced[22m.

     The width of all lines in the plot can be increased by the fac-
     tor <n> specified in [1mlinewidth[22m. Similarly [1mdashlength [22mis a mul-
     tiplier for the default dash spacing.

     [1mrounded [22msets line caps and line joins to be rounded; [1mbutt [22mis
     the default, butt caps and mitered joins.

     The default size for PDF output is 5 inches by 3 inches. The
     [1msize [22moption changes this to whatever the user requests. By
     default the X and Y sizes are taken to be in inches, but other
     units are possible (currently only cm).
















GNUPLOT 4.1                                                      267


     [1m53.52.  Pm[0m


     The [1mpm [22mterminal driver provides an OS/2 Presentation Manager
     window in which the graph is plotted.  The window is opened
     when the first graph is plotted.  This window has its own
     online help as well as facilities for printing, copying to the
     clipboard and some line type and color adjustments.  The [1mmulti-[0m
     [1mplot [22moption is supported.

     Syntax:
           set terminal pm {server {n}} {persist} {widelines}
     {enhanced} {"title"}

     If [1mpersist [22mis specified, each graph appears in its own window
     and all windows remain open after [1mgnuplot [22mexits.  If [1mserver [22mis
     specified, all graphs appear in the same window, which remains
     open when [1mgnuplot [22mexits.  This option takes an optional numeri-
     cal argument which specifies an instance of the server process.
     Thus multiple server windows can be in use at the same time.

     If [1mwidelines [22mis specified, all plots will be drawn with wide
     lines.  If [1menhanced [22mis specified, sub- and superscripts and
     multiple fonts are enabled using the same syntax as the
     [1menhanced postscript [22moption (see [1mset terminal postscript[0m
     [1menhanced [22mfor details).  Font names for the basic PostScript
     fonts may be abbreviated to single letters.

     If [1mtitle [22mis specified, it will be used as the title of the plot
     window.  It will also be used as the name of the server
     instance, and will override the optional numerical argument.

     Linewidths may be changed with [1mset linestyle[22m.



     [1m53.53.  Png[0m


     Syntax:
           set terminal png
                  {{no}transparent} {{no}interlace}
                  {{no}truecolor} {rounded|butt}
                  {tiny | small | medium | large | giant}
                  {font <face> {<pointsize>}}
                  {size <x>,<y>} {{no}crop}
                  {{no}enhanced}
                  {<color0> <color1> <color2> ...}

     PNG images are created using libgd, with optional support for
     TrueType and Adobe Type 1 fonts via libfreetype. Version 1.8 or
     greater of libgd is required.











GNUPLOT 4.1                                                      268


     [1mtransparent [22minstructs the driver to generate transparent PNGs.
     The first color will be the transparent one. Default is
     [1mnotransparent[22m.

     [1minterlace [22minstructs the driver to generate interlaced PNGs.
     Default is [1mnointerlace[22m.

     [1mbutt [22minstructs the driver to use a line drawing method that
     does not overshoot the desired end point of a line.  This set-
     ting is only applicable for line widths greater than 1.  This
     setting is most useful when drawing horizontal or vertical
     lines.  Default is [1mrounded[22m.  Version 2.0 or greater of libgd is
     required.

     PNG plots may be conveniently viewed by piping the output to
     the 'display' program from the ImageMagick package as follows:
                    set term png
                    set output '| display png:-'

     View the output from successive plot commands interactively by
     hitting <space> in the display window.  To save a particular
     one to disk, left click in the display window and choose [1msave[22m.

     Five basic fonts are supported directly by the gd library.
     These are [1mtiny [22m(5x8 pixels), [1msmall [22m(6x12 pixels), [1mmedium[22m, (7x13
     Bold), [1mlarge [22m(8x16) or [1mgiant [22m(9x15 pixels). These fonts cannot
     be scaled or rotated (pure horizontal or vertical text only).

     If gnuplot was built with support for TrueType (*.ttf) or Adobe
     Type 1 (*.pfa) fonts, they may be selected using the 'font
     <face> {<pointsize>}' option. <face> is either the full path-
     name to the font file, or a font face name that is assumed to
     be the first part of a filename in one of the directories
     listed in the GDFONTPATH environmental variable. That is, 'set
     term png font "Face"' will look for a font file named either
     <somedirectory>/Face.ttf or <somedirectory>/Face.pfa. Both
     TrueType and Adobe Type 1 fonts are fully scalable and may be
     rotated through any angle.  If no font is specified, gnuplot
     checks the environmental variable GNUPLOT_DEFAULT_GDFONT to see
     if there is a preferred default font.

     [1menhanced [22menables the enhanced text processing features, (sub-
     scripts, superscripts and mixed fonts). See [1menhanced [22mfor more
     information.  The full enhanced mode syntax is supported by the
     PNG/JPEG driver itself, but some of these features are depen-
     dent on which version of the underlying libgd library is
     present, and which fonts are available.

     The size <x,y> is given in pixels---it defaults to 640x480.
     The number of pixels can be also modified by scaling with the
     [1mset size [22mcommand.  [1mcrop [22mtrims blank space from the edges of the
     completed plot, resulting in a smaller final image size.
     Default is [1mnocrop[22m.










GNUPLOT 4.1                                                      269


     Each color must be of the form 'xrrggbb', where x is the lit-
     eral character 'x' and 'rrggbb' are the red, green and blue
     components in hex.  For example, 'x00ff00' is green.  The back-
     ground color is set first, then the border colors, then the X &
     Y axis colors, then the plotting colors.  The maximum number of
     colors that can be set is 256.

     Examples:
           set terminal png medium size 640,480 \
                            xffffff x000000 x404040 \
                            xff0000 xffa500 x66cdaa xcdb5cd \
                            xadd8e6 x0000ff xdda0dd x9500d3    #
     defaults

     which uses white for the non-transparent background, black for
     borders, gray for the axes, and red, orange, medium aquamarine,
     thistle 3, light blue, blue, plum and dark violet for eight
     plotting colors.

           set terminal png font arial 14 size 800,600

     which searches for a TrueType font with face name 'arial' in
     the directory specified by the environment variable GDFONTPATH
     and 14pt font size.

           set terminal png transparent xffffff \
                            x000000 x202020 x404040 x606060 \
                            x808080 xA0A0A0 xC0C0C0 xE0E0E0

     which uses white for the transparent background, black for bor-
     ders, dark gray for axes, and a gray-scale for the six plotting
     colors.




     [1m53.54.  Postscript[0m


     Several options may be set in the [1mpostscript [22mdriver.

     Syntax:
           set terminal postscript {default}
           set terminal postscript {landscape | portrait | eps}
                                   {enhanced | noenhanced}
                                   {defaultplex | simplex | duplex}
                                   {fontfile [add | delete] "<file-
     name>"
                                    | nofontfiles}
                                   {level1 | leveldefault}
                                   {color | colour | monochrome}
                                   {solid | dashed}
                                   {dashlength | dl <DL>}










GNUPLOT 4.1                                                      270


                                   {linewidth | lw <LW>}
                                   {rounded | butt}
                                   {palfuncparam <samples>{,<maxde-
     viation>}}
                                   {size <XX>{unit},<YY>{unit}}
                                   {blacktext | colortext | colour-
     text}
                                   {{font} "fontname{,fontsize}"
     {<fontsize>}}
     If you see the error message
           "Can't find PostScript prologue file ... "
     Please see and follow the instructions in [1mpostscript prologue[22m.


     [1mlandscape [22mand [1mportrait [22mchoose the plot orientation.  [1meps [22mmode
     generates EPS (Encapsulated PostScript) output, which is just
     regular PostScript with some additional lines that allow the
     file to be imported into a variety of other applications.  (The
     added lines are PostScript comment lines, so the file may still
     be printed by itself.)  To get EPS output, use the [1meps [22mmode and
     make only one plot per file.  In [1meps [22mmode the whole plot,
     including the fonts, is reduced to half of the default size.

     [1menhanced [22menables enhanced text mode features (subscripts,
     superscripts and mixed fonts). See [1menhanced [22mfor more informa-
     tion.  [1mblacktext [22mforces all text to be written in black even in
     color mode;

     Duplexing in PostScript is the ability of the printer to print
     on both sides of the same sheet of paper.  With [1mdefaultplex[22m,
     the default setting of the printer is used; with [1msimplex [22monly
     one side is printed; [1mduplex [22mprints on both sides (ignored if
     your printer can't do it).

     [1m"<fontname>" [22mis the name of a valid PostScript font; and [1m<font-[0m
     [1msize> [22mis the size of the font in PostScript points.  In addi-
     tion to the standard postscript fonts, an oblique version of
     the Symbol font, useful for mathematics, is defined. It is
     called "Symbol-Oblique".

     [1mdefault [22msets all options to their defaults: [1mlandscape[22m,
     [1mmonochrome[22m, [1mdashed[22m, [1mdl 1.0[22m, [1mlw 1.0[22m, [1mdefaultplex[22m, [1mnoenhanced[22m,
     "Helvetica" and 14pt.  Default size of a PostScript plot is 10
     inches wide and 7 inches high.  The option [1mcolor [22menables color,
     while [1mmonochrome [22mprefers black and white drawing elements. Fur-
     ther, [1mmonochrome [22muses gray [1mpalette [22mbut it does not change color
     of objects specified with an explicit [1mcolorspec[22m.  [1msolid [22mdraws
     all plots with solid lines, overriding any dashed patterns.
     [1mdashlength [22mor [1mdl [22mscales the length of the dashed-line segments
     by <DL>, which is a floating-point number greater than zero.
     [1mlinewidth [22mor [1mlw [22mscales all linewidths by <LW>.

     By default the generated PostScript code uses language features










GNUPLOT 4.1                                                      271


     that were introduced in PostScript Level 2, notably filters and
     pattern-fill of irregular objects such as filledcurves.
     PostScript Level 2 features are conditionally protected so that
     PostScript Level 1 interpreters do not issue errors but,
     rather, display a message or a PostScript Level 1 approxima-
     tion.  The [1mlevel1 [22moption substitutes PostScript Level 1 approx-
     imations of these features and uses no PostScript Level 2 code.
     This may be required by some old printers and old versions of
     Adobe Illustrator.  The flag [1mlevel1 [22mcan be toggled later by
     editing a single line in the PostScript output file to force
     PostScript Level 1 interpretation.  In the case of files con-
     taining level 2 code, the above features will not appear or
     will be replaced by a note when this flag is set or when the
     interpreting program does not indicate that it understands
     level 2 PostScript or higher.

     [1mrounded [22msets line caps and line joins to be rounded; [1mbutt [22mis
     the default, butt caps and mitered joins;

     [1mpalfuncparam [22mcontrols how [1mset palette functions [22mare encoded as
     gradients in the output. Analytic color component functions
     (set via [1mset palette functions[22m) are encoded as linear interpo-
     lated gradients in the postscript output:  The color component
     functions are sampled at <samples> points and all points are
     removed from this gradient which can be removed without chang-
     ing the resulting colors by more than <maxdeviation>. For
     almost every useful palette you may savely leave the defaults
     of <samples>=2000 and <maxdeviation>=0.003 untouched.

     The default size for postscript output is 10 inches x 7 inches.
     The default for eps output is 5 x 3.5 inches.  The [1msize [22moption
     changes this to whatever the user requests. By default the X
     and Y sizes are taken to be in inches, but other units are pos-
     sibly (currently only cm). The BoundingBox of the plot is cor-
     rectly adjusted to contain the resized image.  Screen coordi-
     nates always run from 0.0 to 1.0 along the full length of the
     plot edges as specified by the [1msize [22moption.  NB: [1mthis is a[0m
     [1mchange from the previously recommended method of using the set[0m
     [1msize command prior to setting the terminal type[22m.  The old
     method left the BoundingBox unchanged and screen coordinates
     did not correspond to the actual limits of the plot.

     Fonts listed by [1mfontfile [22mor [1mfontfile add [22mencapsulate the font
     definitions of the listed font from a postscript Type 1 or
     TrueType font file directly into the gnuplot output postscript
     file.  Thus, the enclosed font can be used in labels, titles,
     etc.  See the section [1mpostscript fontfile [22mfor more details.
     With [1mfontfile delete[22m, a fontfile is deleted from the list of
     embedded files.  [1mnofontfiles [22mcleans the list of embedded fonts.

     Examples:
           set terminal postscript default       # old postscript
           set terminal postscript enhanced      # old enhpost










GNUPLOT 4.1                                                      272


           set terminal postscript landscape 22  # old psbig
           set terminal postscript eps 14        # old epsf1
           set terminal postscript eps 22        # old epsf2
           set size 0.7,1.4; set term post portrait color "Times-
     Roman" 14
           set term post "VAGRoundedBT_Regular" 14 fontfile
     "bvrr8a.pfa"

     Linewidths and pointsizes may be changed with [1mset style line[22m.

     The [1mpostscript [22mdriver supports about 70 distinct pointtypes,
     selectable through the [1mpointtype [22moption on [1mplot [22mand [1mset style[0m
     [1mline[22m.

     Several possibly useful files about [1mgnuplot[22m's PostScript are
     included in the /docs/psdoc subdirectory of the [1mgnuplot [22mdistri-
     bution and at the distribution sites.  These are "ps_sym-
     bols.gpi" (a [1mgnuplot [22mcommand file that, when executed, creates
     the file "ps_symbols.ps" which shows all the symbols available
     through the [1mpostscript [22mterminal), "ps_guide.ps" (a PostScript
     file that contains a summary of the enhanced syntax and a page
     showing what the octal codes produce with text and symbol
     fonts), "ps_file.doc" (a text file that contains a discussion
     of the organization of a PostScript file written by [1mgnuplot[22m),
     and "ps_fontfile_doc.tex" (a LaTeX file which contains a short
     documentation concerning the encapsulation of LaTeX fonts with
     a glyph table of the math fonts).

     A PostScript file is editable, so once [1mgnuplot [22mhas created one,
     you are free to modify it to your heart's desire.  See the
     [1mediting postscript [22msection for some hints.




          [1m53.54.1.  Enhanced postscript[0m


          Several terminal types support an enhanced text mode in
          which additional formatting information is embedded in the
          text string.






















GNUPLOT 4.1                                                      273


  +--------------------------------------------------------------+
  |Control     Examples      Explanation                         |
  +--------------------------------------------------------------+
  |   ^           a^x        superscript                         |
  |   _           a_x        subscript                           |
  |   @       @x or a@^b_c   phantom box (occupies no width)     |
  |   &         &{space}     inserts space of specified length   |
  |   ~         ~a{.8-}      overprints '-' on 'a', raised by .8 |
  |                          times the current fontsize          |
  +--------------------------------------------------------------+



Braces can be used to place multiple-character text where a single
character is expected (e.g., 2^{10}).  To change the font and/or
size, use the full form:  {/[fontname][=fontsize | *fontscale]
text}.  Thus {/Symbol=20 G} is a 20-point GAMMA and {/*0.75 K} is a
K at three-quarters of whatever fontsize is currently in effect.
(The '/' character MUST be the first character after the '{'.)

If the encoding vector has been changed by [1mset encoding[22m, the default
encoding vector can be used instead by following the slash with a
dash.  This is unnecessary if you use the Symbol font, how-
ever---since /Symbol uses its own encoding vector, [1mgnuplot [22mwill not
apply any other encoding vector to it.

The phantom box is useful for a@^b_c to align superscripts and sub-
scripts but does not work well for overwriting an accent on a let-
ter.  (To do the latter, it is much better to use 'set encoding
iso_8859_1' to change to the ISO Latin-1 encoding vector, which con-
tains a large variety of letters with accents or other diacritical
marks.)  Since the box is non-spacing, it is sensible to put the
shorter of the subscript or superscript in the box (that is, after
the @).

Space equal in length to a string can be inserted using the '&'
character.  Thus
        'abc&{def}ghi'
would produce
        'abc   ghi'.

The '~' character causes the next character or bracketed text to be
overprinted by the following character or bracketed text.  The sec-
ond text will be horizontally centered on the first.  Thus '~a/'
will result in an 'a' with a slash through it.  You can also shift
the second text vertically by preceding the second text with a num-
ber, which will define the fraction of the current fontsize by which
the text will be raised or lowered.  In this case the number and
text must be enclosed in brackets because more than one character is
necessary.  If the overprinted text begins with a number, put a
space between the vertical offset and the text ('~{abc}{.5 000}');
otherwise no space is needed ('~{abc}{.5---}').  You can change the
font for one or both strings ('~a{.5 /*.2 o}'---an 'a' with a one-










GNUPLOT 4.1                                                      274


fifth-size 'o' on top---and the space between the number and the
slash is necessary), but you can't change it after the beginning of
the string.  Neither can you use any other special syntax within
either string.  You can, of course, use control characters by escap-
ing them (see below), such as '~a{\^}'

You can access special symbols numerically by specifying \character-
code (in octal), e.g., {/Symbol \245} is the symbol for infinity.

You can escape control characters using \, e.g.,  \\, \{, and so on.

But be aware that strings in double-quotes are parsed differently
than those enclosed in single-quotes.  The major difference is that
backslashes may need to be doubled when in double-quoted strings.

Examples (these are hard to describe in words---try them!):
      set xlabel 'Time (10^6 {/Symbol m}s)'
      set title '{/Symbol=18 \362@_{/=9.6 0}^{/=12 x}} \
                 {/Helvetica e^{-{/Symbol m}^2/2} d}{/Symbol m}'

The file "ps_guide.ps" in the /docs/psdoc subdirectory of the [1mgnu-[0m
[1mplot [22msource distribution contains more examples of the enhanced syn-
tax.



          [1m53.54.2.  Editing postscript[0m


          The PostScript language is a very complex language---far
          too complex to describe in any detail in this document.
          Nevertheless there are some things in a PostScript file
          written by [1mgnuplot [22mthat can be changed without risk of
          introducing fatal errors into the file.

          For example, the PostScript statement "/Color true def"
          (written into the file in response to the command [1mset ter-[0m
          [1mminal postscript color[22m), may be altered in an obvious way
          to generate a black-and-white version of a plot.  Simi-
          larly line colors, text colors, line weights and symbol
          sizes can also be altered in straight-forward ways.  Text
          (titles and labels) can be edited to correct misspellings
          or to change fonts.  Anything can be repositioned, and of
          course anything can be added or deleted, but modifications
          such as these may require deeper knowledge of the
          PostScript language.

          The organization of a PostScript file written by [1mgnuplot[0m
          is discussed in the text file "ps_file.doc" in the docs/ps
          subdirectory of the gnuplot source distribution.













GNUPLOT 4.1                                                      275


          [1m53.54.3.  Postscript fontfile[0m


          The [1mfontfile [22mor [1mfontfile add [22moption takes one file name as
          argument and encapsulates this file into the postscript
          output in order to make this font available for text ele-
          ments (labels, tic marks, titles, etc.).  The [1mfontfile[0m
          [1mdelete [22moption also takes one file name as argument. It
          deletes this file name from the list of encapsulated
          files.

          The postscript terminal understands some font file for-
          mats: Type 1 fonts in ASCII file format (extension
          ".pfa"), Type 1 fonts in binary file format (extension
          ".pfb"), and TrueType fonts (extension ".ttf"). Pfa files
          are understood directly, pfb and ttf files are converted
          on the fly if appropriate conversion tools are installed
          (see below). You have to specify the full filename includ-
          ing the extension. Each [1mfontfile [22moption takes exact one
          font file name. This option can be used multiple times in
          order to include more than one font file.

          The font file is searched in the working directory and in
          all directories listed in the fontpath which is determined
          by [1mset fontpath[22m.  In addition, the fontpath can be set
          using the environment variable GNUPLOT_FONTPATH. If this
          is not set a system dependent default search list is used.
          See [1mset fontpath [22mfor more details.

          For using the encapsulated font file you have to specify
          the font name (which normally is not the same as the file
          name). When embedding a font file by using the [1mfontfile[0m
          option in interactive mode, the font name is printed on
          the screen. E.g.
             Font file 'p052004l.pfb' contains the font 'URWPalla-
          dioL-Bold'. Location:
             /usr/lib/X11/fonts/URW/p052004l.pfb

          When using pfa or pfb fonts, you can also find it out by
          looking into the font file. There is a line similar to
          "/FontName /URWPalladioL-Bold def".  The middle string
          without the slash is the fontname, here "URWPalladioL-
          Bold".  For TrueType fonts, this is not so easy since the
          font name is stored in a binary format. In addition, they
          often have spaces in the font names which is not supported
          by Type 1 fonts (in which a TrueType is converted on the
          fly). The font names are changed in order to eliminate the
          spaces in the fontnames. The easiest way to find out which
          font name is generated for use with gnuplot, start gnuplot
          in interactive mode and type in "set terminal postscript
          fontfile '<filename.ttf>'".

          For converting font files (either ttf or pfb) to pfa










GNUPLOT 4.1                                                      276


          format, the conversion tool has to read the font from a
          file and write it to standard output. If the output cannot
          be written to standard output, on-the-fly conversion is
          not possible.

          For pfb files "pfbtops" is a tool which can do this. If
          this program is installed on your system the on the fly
          conversion should work.  Just try to encapsulate a pfb
          file. If the compiled in program call does not work cor-
          rectly you can specify how this program is called by
          defining the environment variable GNUPLOT_PFBTOPFA e.g. to
          "pfbtops %s". The [1m%s [22mwill be replaced by the font file
          name and thus has to exist in the string.

          If you don't want to do the conversion on the fly but get
          a pfa file of the font you can use the tool "pfb2pfa"
          which is written in simple c and should compile with any c
          compiler.  It is available from many ftp servers, e.g.
                    ftp://ftp.dante.de/tex-archive/fonts/utili-
          ties/ps2mf/
          In fact, "pfbtopfa" and "pfb2ps" do the same job.
          "pfbtopfa" puts the resulting pfa code into a file,
          whereas "pfbtops" writes it to standard output.

          TrueType fonts are converted into Type 1 pfa format, e.g.
          by using the tool "ttf2pt1" which is available from
                    http://ttf2pt1.sourceforge.net/
          If the builtin conversion does not work, the conversion
          command can be changed by the environment variable GNU-
          PLOT_TTFTOPFA. For usage with ttf2pt1 it may be set to
          "ttf2pt1 -a -e -W 0 %s - ". Here again, [1m%s [22mstands for the
          file name.

          For special purposes you also can use a pipe (if available
          for your operating system). Therefore you start the file
          name definition with the character "<" and append a pro-
          gram call. This program has to write pfa data to standard
          output. Thus, a pfa file may be accessed by [1mset fontfile[0m
          [1m"< cat garamond.pfa"[22m.

          For example, including Type 1 font files can be used for
          including the postscript output in LaTeX documents. The
          "european computer modern" font (which is a variant of the
          "computer modern" font) is available in pfb format from
          any CTAN server, e.g.
                    ftp://ftp.dante.de/tex-archive/fonts/ps-
          type1/cm-super/
          For example, the file "sfrm1000.pfb" contains the normal
          upright fonts with serifs in the design size 10pt (font
          name "SFRM1000").  The computer modern fonts, which are
          still necessary for mathematics, are available from
                    ftp://ftp.dante.de/tex-archive/fonts/cm/ps-
          type1/bluesky










GNUPLOT 4.1                                                      277


          With these you can use any character available in TeX.
          However, the computer modern fonts have a strange encod-
          ing. (This is why you should not use cmr10.pfb for text,
          but sfrm1000.pfb instead.)  The usage of TeX fonts is
          shown in one of the demos.  The file "ps_fontfile_doc.tex"
          in the /docs/psdoc subdirectory of the [1mgnuplot [22msource dis-
          tribution contains a table with glyphs of the TeX math-
          fonts.

          If the font "CMEX10" is embedded (file "cmex10.pfb") gnu-
          plot defines the additional font "CMEX10-Baseline". It is
          shifted vertically in order to fit better to the other
          glyphs (CMEX10 has its baseline at the top of the sym-
          bols).



          [1m53.54.4.  Postscript prologue[0m


          Each PostScript output file includes a %%Prolog section
          and possibly some additional user-defined sections con-
          taining, for example, character encodings. These sections
          are copied from a set of PostScript prologue files which
          are either compiled in the gnuplot executable or stored
          elsewhere on your computer. This behaviour and the default
          directory where these files live are controlled at the
          time gnuplot is built. However, you can control this
          either by defining an environment variable GNUPLOT_PS_DIR
          or by using the gnuplot command [1mset loadpath[22m. See [1mset[0m
          [1mloadpath[22m.





     [1m53.55.  Pslatex and pstex[0m


     The [1mpslatex [22mdriver generates output for further processing by
     LaTeX, while the [1mpstex [22mdriver generates output for further pro-
     cessing by TeX. [1mpslatex [22muses \specials understandable by dvips
     and xdvi. Figures generated by [1mpstex [22mcan be included in any
     plain-based format (including LaTeX).

     Syntax:
           set terminal [pslatex | pstex] {default}
           set terminal [pslatex | pstex]
                                   {rotate | norotate}
                                   {oldstyle | newstyle}
                                   {auxfile | noauxfile}
                                   {level1 | leveldefault}
                                   {color | colour | monochrome}










GNUPLOT 4.1                                                      278


                                   {solid | dashed}
                                   {dashlength | dl <DL>}
                                   {linewidth | lw <LW>}
                                   {rounded | butt}
                                   {palfuncparam <samples>{,<maxde-
     viation>}}
                                   {size <XX>{unit},<YY>{unit}}
                                   {<font_size>}

     If you see the error message
           "Can't find PostScript prologue file ... "
     Please see and follow the instructions in [1mpostscript prologue[22m.

     The option [1mcolor [22menables color, while [1mmonochrome [22mprefers black
     and white drawing elements. Further, [1mmonochrome [22muses gray
     [1mpalette [22mbut it does not change color of objects specified with
     an explicit [1mcolorspec[22m.  [1msolid [22mdraws all plots with solid lines,
     overriding any dashed patterns.  [1mdashlength [22mor [1mdl [22mscales the
     length of the dashed-line segments by <DL>, which is a float-
     ing-point number greater than zero.  [1mlinewidth [22mor [1mlw [22mscales all
     linewidths by <LW>.

     By default the generated PostScript code uses language features
     that were introduced in PostScript Level 2, notably filters and
     pattern-fill of irregular objects such as filledcurves.
     PostScript Level 2 features are conditionally protected so that
     PostScript Level 1 interpreters do not issue errors but,
     rather, display a message or a PostScript Level 1 approxima-
     tion.  The [1mlevel1 [22moption substitutes PostScript Level 1 approx-
     imations of these features and uses no PostScript Level 2 code.
     This may be required by some old printers and old versions of
     Adobe Illustrator.  The flag [1mlevel1 [22mcan be toggled later by
     editing a single line in the PostScript output file to force
     PostScript Level 1 interpretation.  In the case of files con-
     taining level 2 code, the above features will not appear or
     will be replaced by a note when this flag is set or when the
     interpreting program does not indicate that it understands
     level 2 PostScript or higher.

     [1mrounded [22msets line caps and line joins to be rounded; [1mbutt [22mis
     the default, butt caps and mitered joins;

     [1mpalfuncparam [22mcontrols how [1mset palette functions [22mare encoded as
     gradients in the output. Analytic color component functions
     (set via [1mset palette functions[22m) are encoded as linear interpo-
     lated gradients in the postscript output:  The color component
     functions are sampled at <samples> points and all points are
     removed from this gradient which can be removed without chang-
     ing the resulting colors by more than <maxdeviation>. For
     almost every useful palette you may savely leave the defaults
     of <samples>=2000 and <maxdeviation>=0.003 untouched.

     The default size for postscript output is 10 inches x 7 inches.










GNUPLOT 4.1                                                      279


     The default for eps output is 5 x 3.5 inches.  The [1msize [22moption
     changes this to whatever the user requests. By default the X
     and Y sizes are taken to be in inches, but other units are pos-
     sibly (currently only cm). The BoundingBox of the plot is cor-
     rectly adjusted to contain the resized image.  Screen coordi-
     nates always run from 0.0 to 1.0 along the full length of the
     plot edges as specified by the [1msize [22moption.  NB: [1mthis is a[0m
     [1mchange from the previously recommended method of using the set[0m
     [1msize command prior to setting the terminal type[22m.  The old
     method left the BoundingBox unchanged and screen coordinates
     did not correspond to the actual limits of the plot.

     if [1mrotate [22mis specified, the y-axis label is rotated.
     <font_size> is the size (in pts) of the desired font.

     If [1mauxfile [22mis specified, it directs the driver to put the
     PostScript commands into an auxiliary file instead of directly
     into the LaTeX file.  This is useful if your pictures are large
     enough that dvips cannot handle them.  The name of the auxil-
     iary PostScript file is derived from the name of the TeX file
     given on the [1mset output [22mcommand; it is determined by replacing
     the trailing [1m.tex [22m(actually just the final extent in the file
     name) with [1m.ps [22min the output file name, or, if the TeX file has
     no extension, [1m.ps [22mis appended.  The [1m.ps [22mis included into the
     [1m.tex [22mfile by a \special{psfile=...} command.  Remember to close
     the [1moutput file [22mbefore next plot unless in [1mmultiplot [22mmode.

     Gnuplot versions prior version 4.2 have generated plots of the
     size 5 x 3 inches using the ps(la)tex terminal while the cur-
     rent version generates 5 x 3.5 inches to be consistent with the
     postscript eps terminal.  In addition, the character width is
     now estimated to be 60% of the font size while the old epslatex
     terminal used 50%. To reach the old format specify the option
     [1moldstyle[22m.

     The pslatex driver offers a special way of controlling text
     positioning: (a) If any text string begins with '{', you also
     need to include a '}' at the end of the text, and the whole
     text will be centered both horizontally and vertically by
     LaTeX.  (b) If the text string begins with '[', you need to
     continue it with: a position specification (up to two out of
     t,b,l,r), ']{', the text itself, and finally, '}'. The text
     itself may be anything LaTeX can typeset as an LR-box.
     \rule{}{}'s may help for best positioning.

     The options not described here are identical to the [1mPostscript[0m
     [1mterminal[22m.  Look there if you want to know what they do.

     Examples:
           set term pslatex monochrome dashed rotate       # set to
     defaults
     To write the PostScript commands into the file "foo.ps":
           set term pslatex auxfile










GNUPLOT 4.1                                                      280


           set output "foo.tex"; plot ...; set output
     About label positioning: Use gnuplot defaults (mostly sensible,
     but sometimes not really best):
            set title '\LaTeX\ -- $ \gamma $'
     Force centering both horizontally and vertically:
            set label '{\LaTeX\ -- $ \gamma $}' at 0,0
     Specify own positioning (top here):
            set xlabel '[t]{\LaTeX\ -- $ \gamma $}'
     The other label -- account for long ticlabels:
            set ylabel '[r]{\LaTeX\ -- $ \gamma $\rule{7mm}{0pt}}'

     Linewidths and pointsizes may be changed with [1mset style line[22m.



     [1m53.56.  Pstricks[0m


     The [1mpstricks [22mdriver is intended for use with the "pstricks.sty"
     macro package for LaTeX.  It is an alternative to the [1meepic [22mand
     [1mlatex [22mdrivers.  You need "pstricks.sty", and, of course, a
     printer that understands PostScript, or a converter such as
     Ghostscript.

     PSTricks is available via anonymous ftp from the /pub directory
     at Princeton.edu.  This driver definitely does not come close
     to using the full capability of the PSTricks package.

     Syntax:
           set terminal pstricks {hacktext | nohacktext} {unit |
     nounit}

     The first option invokes an ugly hack that gives nicer numbers;
     the second has to do with plot scaling.  The defaults are [1mhack-[0m
     [1mtext [22mand [1mnounit[22m.



     [1m53.57.  Qms[0m


     The [1mqms [22mterminal driver supports the QMS/QUIC Laser printer,
     the Talaris 1200 and others.  It has no options.



     [1m53.58.  Regis[0m


     The [1mregis [22mterminal device generates output in the REGIS graph-
     ics language.  It has the option of using 4 (the default) or 16
     colors.











GNUPLOT 4.1                                                      281


     Syntax:
           set terminal regis {4 | 16}



     [1m53.59.  Rgip[0m


     The [1mrgip [22mand [1muniplex [22mterminal drivers support RGIP metafiles.
     They can combine several graphs on a single page, but only one
     page is allowed in a given output file.

     Syntax:
           set terminal rgip | uniplex {portrait | landscape}
                                       {[<horiz>,<vert>]} {<font-
     size>}

     permissible values for the font size are in the range 1--8,
     with the default being 1.  The default layout is landscape.
     Graphs are placed on the page in a [1mhoriz[22mx[1mvert [22mgrid, which
     defaults to [1,1].

     Example:
           set terminal uniplex portrait [2,3]

     puts six graphs on a page in three rows of two in portrait ori-
     entation.



     [1m53.60.  Sun[0m


     The [1msun [22mterminal driver supports the SunView window system.  It
     has no options.



     [1m53.61.  Svg[0m


     This terminal produces files in the W3C Scalable Vector Graph-
     ics format.

     Syntax:
           set terminal svg {size <x>,<y> {|fixed|dynamic}}
                            {{no}enhanced}
                            {fname "<font>"} {fsize <fontsize>}
                            {font "<fontname>{,<fontsize>}"}
                            {fontfile <filename>}
                            {rounded|butt} {linewidth <lw>}

     where <x> and <y> are the size of the SVG plot to generate,










GNUPLOT 4.1                                                      282


     [1mdynamic [22mallows a svg-viewer to resize plot, whereas the default
     setting, [1mfixed[22m, will request an absolute size.

     [1mlinewidth <w> [22mincreases the width of all lines used in the fig-
     ure by a factor of <w>.

     <font> is the name of the default font to use (default Arial)
     and <fontsize> is the font size (in points, default 12). Gnu-
     plot does not currently provide a mechanism for embedding fonts
     in the output file, so svg viewing programs may substitute
     other fonts when the file is displayed.

     The svg terminal supports an enhanced text mode, which allows
     font and other formatting commands to be embedded in labels and
     other text strings. The enhanced text mode syntax is shared
     with other gnuplot terminal types. See [1menhanced [22mfor more
     details.

     SVG allows you to embed fonts directly into an SVG document, or
     to provide a hypertext link to the desired font. The [1mfontfile[0m
     option specifies a local file which is copied into the <defs>
     section of the resulting SVG output file.  This file may either
     itself contain a font, or may contain the records necessary to
     create a hypertext reference to the desired font. Gnuplot will
     look for the requested file using the directory list in the
     GNUPLOT_FONTPATH environmental variable.



     [1m53.62.  Svga[0m


     The [1msvga [22mterminal driver supports PCs with SVGA graphics.  It
     can only be used if it is compiled with DJGPP.  Its only option
     is the font.

     Syntax:
           set terminal svga {"<fontname>"}



     [1m53.63.  Tek40[0m


     This family of terminal drivers supports a variety of VT-like
     terminals.  [1mtek40xx [22msupports Tektronix 4010 and others as well
     as most TEK emulators; [1mvttek [22msupports VT-like tek40xx terminal
     emulators; [1mkc-tek40xx [22msupports MS-DOS Kermit Tek4010 terminal
     emulators in color: [1mkm-tek40xx [22msupports them in monochrome;
     [1mselanar [22msupports Selanar graphics; and [1mbitgraph [22msupports BBN
     Bitgraph terminals.  None have any options.












GNUPLOT 4.1                                                      283


     [1m53.64.  Tek410x[0m


     The [1mtek410x [22mterminal driver supports the 410x and 420x family
     of Tektronix terminals.  It has no options.



     [1m53.65.  Texdraw[0m


     The [1mtexdraw [22mterminal driver supports the LaTeX texdraw environ-
     ment.  It is intended for use with "texdraw.sty" and "tex-
     draw.tex" in the texdraw package.

     Points, among other things, are drawn using the LaTeX commands
     "\Diamond" and "\Box".  These commands no longer belong to the
     LaTeX2e core; they are included in the latexsym package, which
     is part of the base distribution and thus part of any LaTeX
     implementation.  Please do not forget to use this package.

     It has no options.



     [1m53.66.  Tgif[0m


     Tgif is an X11-based drawing tool---it has nothing to do with
     GIF.

     The [1mtgif [22mdriver supports different pointsizes (with [1mset point-[0m
     [1msize[22m), different label fonts and font sizes (e.g. [1mset label[0m
     [1m"Hallo" at x,y font "Helvetica,34"[22m) and multiple graphs on the
     page.  The proportions of the axes are not changed.

     Syntax:
           set terminal tgif {portrait | landscape | default}
     {<[x,y]>}
                             {monochrome | color}
                             {{linewidth | lw} <LW>}
                             {solid | dashed}
                             {font "<fontname>"} {<fontsize>}

     where <[x,y]> specifies the number of graphs in the x and y
     directions on the page, [1mcolor [22menables color, [1mlinewidth [22mscales
     all linewidths by <LW>, "<fontname>" is the name of a valid
     PostScript font, and <fontsize> specifies the size of the
     PostScript font.  [1mdefaults [22msets all options to their defaults:
     [1mportrait[22m, [1m[1,1][22m, [1mcolor[22m, [1mlinwidth 1.0[22m, [1mdashed[22m, [1m"Helvetica"[22m, and
     [1m18[22m.

     The [1msolid [22moption is usually prefered if lines are colored, as










GNUPLOT 4.1                                                      284


     they often are in the editor.  Hardcopy will be black-and-
     white, so [1mdashed [22mshould be chosen for that.

     Multiplot is implemented in two different ways.

     The first multiplot implementation is the standard gnuplot mul-
     tiplot feature:

           set terminal tgif
           set output "file.obj"
           set multiplot
           set origin x01,y01
           set size  xs,ys
           plot ...
                ...
           set origin x02,y02
           plot ...
           unset multiplot

     See [1mset multiplot [22mfor further information.

     The second version is the [x,y] option for the driver itself.
     The advantage of this implementation is that everything is
     scaled and placed automatically without the need for setting
     origins and sizes; the graphs keep their natural x/y propor-
     tions of 3/2 (or whatever is fixed by [1mset size[22m).

     If both multiplot methods are selected, the standard method is
     chosen and a warning message is given.

     Examples of single plots (or standard multiplot):
           set terminal tgif                  # defaults
           set terminal tgif "Times-Roman" 24
           set terminal tgif landscape
           set terminal tgif landscape solid

     Examples using the built-in multiplot mechanism:
           set terminal tgif portrait [2,4]  # portrait; 2 plots in
     the x-
                                             # and 4 in the y-direc-
     tion
           set terminal tgif [1,2]           # portrait; 1 plot in
     the x-
                                             # and 2 in the y-direc-
     tion
           set terminal tgif landscape [3,3] # landscape; 3 plots in
     both
                                             # directions















GNUPLOT 4.1                                                      285


     [1m53.67.  Tkcanvas[0m


     This terminal driver generates Tk canvas widget commands based
     on Tcl/Tk (default) or Perl.  To use it, rebuild [1mgnuplot [22m(after
     uncommenting or inserting the appropriate line in "term.h"),
     then

      gnuplot> set term tkcanvas {perltk} {interactive}
      gnuplot> set output 'plot.file'

     After invoking "wish", execute the following sequence of Tcl/Tk
     commands:

      % source plot.file
      % canvas .c
      % pack .c
      % gnuplot .c

     Or, for Perl/Tk use a program like this:

      use Tk;
      my $top = MainWindow->new;
      my $c = $top->Canvas->pack;
      my $gnuplot = do "plot.pl";
      $gnuplot->($c);
      MainLoop;

     The code generated by [1mgnuplot [22mcreates a procedure called "gnu-
     plot" that takes the name of a canvas as its argument.  When
     the procedure is called, it clears the canvas, finds the size
     of the canvas and draws the plot in it, scaled to fit.

     For 2-dimensional plotting ([1mplot[22m) two additional procedures are
     defined: "gnuplot_plotarea" will return a list containing the
     borders of the plotting area "xleft, xright, ytop, ybot" in
     canvas screen coordinates, while the ranges of the two axes
     "x1min, x1max, y1min, y1max, x2min, x2max, y2min, y2max" in
     plot coordinates can be obtained calling "gnuplot_axisranges".
     If the "interactive" option is specified, mouse clicking on a
     line segment will print the coordinates of its midpoint to std-
     out. Advanced actions can happen instead if the user supplies a
     procedure named "user_gnuplot_coordinates", which takes the
     following arguments: "win id x1s y1s x2s y2s x1e y1e x2e y2e
     x1m y1m x2m y2m", the name of the canvas and the id of the line
     segment followed by the coordinates of its start and end point
     in the two possible axis ranges; the coordinates of the mid-
     point are only filled for logarithmic axes.

     The current version of [1mtkcanvas [22msupports neither [1mmultiplot [22mnor
     [1mreplot[22m.












GNUPLOT 4.1                                                      286


     [1m53.68.  Tpic[0m


     The [1mtpic [22mterminal driver supports the LaTeX picture environment
     with tpic \specials.  It is an alternative to the [1mlatex [22mand
     [1meepic [22mterminal drivers.  Options are the point size, line
     width, and dot-dash interval.

     Syntax:
           set terminal tpic <pointsize> <linewidth> <interval>

     where [1mpointsize [22mand [1mlinewidth [22mare integers in milli-inches and
     [1minterval [22mis a float in inches.  If a non-positive value is
     specified, the default is chosen: pointsize = 40, linewidth =
     6, interval = 0.1.

     All drivers for LaTeX offer a special way of controlling text
     positioning: If any text string begins with '{', you also need
     to include a '}' at the end of the text, and the whole text
     will be centered both horizontally and vertically by LaTeX. ---
     If the text string begins with '[', you need to continue it
     with: a position specification (up to two out of t,b,l,r),
     ']{', the text itself, and finally, '}'. The text itself may be
     anything LaTeX can typeset as an LR-box. \rule{}{}'s may help
     for best positioning.

     Examples: About label positioning: Use gnuplot defaults (mostly
     sensible, but sometimes not really best):
            set title '\LaTeX\ -- $ \gamma $'
     Force centering both horizontally and vertically:
            set label '{\LaTeX\ -- $ \gamma $}' at 0,0
     Specify own positioning (top here):
            set xlabel '[t]{\LaTeX\ -- $ \gamma $}'
     The other label -- account for long ticlabels:
            set ylabel '[r]{\LaTeX\ -- $ \gamma $\rule{7mm}{0pt}}'



     [1m53.69.  Unixpc[0m


     The [1munixpc [22mterminal driver supports AT&T 3b1 and AT&T 7300 Unix
     PC.  It has no options.



     [1m53.70.  Unixplot[0m


     The [1munixplot [22mterminal driver generates output in the Unix
     "plot" graphics language.  It has no options.

     This terminal cannot be compiled if the GNU version of plot is










GNUPLOT 4.1                                                      287


     to be used; in that case, use the [1mgnugraph [22mterminal instead.



     [1m53.71.  Atari ST (via VDI)[0m


     The [1mvdi [22mterminal is the same as the [1matari [22mterminal, except that
     it sends output to the screen via the VDI and not into AES-Win-
     dows.

     The [1mvdi [22mterminal has options to set the character size and the
     screen colors.

     Syntax:
           set terminal vdi {<fontsize>} {<col0> <col1> ... <col15>}

     The character size must appear if any colors are to be speci-
     fied.  Each of the (up to 16) colors is given as a three-digit
     hex number, where the digits represent RED, GREEN and BLUE (in
     that order).  The range of 0--15 is scaled to whatever color
     range the screen actually has.  On a normal ST screen, odd and
     even intensities are the same.

     Examples:
           set terminal vdi 4    # use small (6x6) font
           set terminal vdi 6 0  # set monochrome screen to white on
     black
           set terminal vdi 13 0 fff f00 f0 f ff f0f
                      # set first seven colors to black, white, red,
     green,
                      # blue, cyan, and purple and use large font
     (8x16).

     Additionally, if an environment variable GNUCOLORS exists, its
     contents are interpreted as an options string, but an explicit
     terminal option takes precedence.



     [1m53.72.  Vgagl[0m


     The [1mvgagl [22mdriver is a fast linux console driver with full mouse
     and pm3d support.  It looks at the environment variable
     SVGALIB_DEFAULT_MODE for the default mode; if not set, it uses
     a 256 color mode with the highest available resolution.

     Syntax:
        set terminal vgagl \
                     background [red] [[green] [blue]] \
                     [uniform | interpolate] \
                     [mode]










GNUPLOT 4.1                                                      288


     The color mode can also be given with the mode option. Both
     Symbolic names as G1024x768x256 and integers are allowed. The
     [1mbackground [22moption takes either one or three integers in the
     range [0, 255]. If only one integers is supplied, it is taken
     as gray value for the background.  If three integers are
     present, the background gets the corresponding color.  The
     (mutually exclusive) options [1minterpolate [22mand [1muniform [22mcontrol if
     color interpolation is done while drawing triangles (on by
     default).

     To get high resolution modes, you will probably have to modify
     the configuration file of libvga, usually /etc/vga/libvga.conf.
     Using the VESA fb is a good choice, but this needs to be com-
     piled in the kernel.

     The vgagl driver uses the first *available* vga mode from the
     following list:
      - the driver which was supplied when setting vgagl, e.g. `set
     term vgagl
        G1024x768x256` would first check, if the G1024x768x256 mode
     is available.
      - the environment variable SVGALIB_DEFAULT_MODE
      - G1024x768x256
      - G800x600x256
      - G640x480x256
      - G320x200x256
      - G1280x1024x256
      - G1152x864x256
      - G1360x768x256
      - G1600x1200x256




     [1m53.73.  VWS[0m


     The [1mVWS [22mterminal driver supports the VAX Windowing System.  It
     has no options.  It will sense the display type (monochrome,
     gray scale, or color.)  All line styles are plotted as solid
     lines.



     [1m53.74.  Vx384[0m


     The [1mvx384 [22mterminal driver supports the Vectrix 384 and Tandy
     color printers.  It has no options.














GNUPLOT 4.1                                                      289


     [1m53.75.  Windows[0m


     Three options may be set in the [1mwindows [22mterminal driver.

     Syntax:
           set terminal windows {color | monochrome}
                                {enhanced | noenhanced}
                                {{font} "fontname{,fontsize}"
     {<fontsize>}}

     where [1mcolor [22mand [1mmonochrome [22mselect colored or mono output,
     [1menhanced [22menables enhanced text mode features (subscripts,
     superscripts and mixed fonts). See [1menhanced [22mfor more informa-
     tion.  [1m"<fontname>" [22mis the name of a valid Windows font, and
     [1m<fontsize> [22mis the size of the font in points.

     Other options may be set with the graph-menu, the initializa-
     tion file, and [1mset linestyle[22m.  Note that there is one restric-
     tion imposed by the classic Windows GDI interface: modifiable
     linewidth only works with solid lines, not with dotted or
     dashed ones.

     The Windows version normally terminates immediately as soon as
     the end of any files given as command line arguments is reached
     (i.e. in non-interactive mode), unless you specify [1m- [22mas the
     last command line option.  It will also not show the text-win-
     dow at all, in this mode, only the plot.  By giving the
     optional argument [1m-persist [22m(same as for gnuplot under x11; for-
     mer Windows-only options [1m/noend [22mor [1m-noend [22mare still accepted as
     well), will not close gnuplot. Contrary to gnuplot on other
     operating systems, gnuplot's interactive command line is acces-
     sible after the -persist option.




          [1m53.75.1.  Graph-menu[0m


          The [1mgnuplot graph [22mwindow has the following options on a
          pop-up menu accessed by pressing the right mouse button or
          selecting [1mOptions [22mfrom the system menu:

          [1mBring to Top [22mwhen checked brings the graph window to the
          top after every plot.

          [1mColor [22mwhen checked enables color linestyles.  When
          unchecked it forces monochrome linestyles.

          [1mCopy to Clipboard [22mcopies a bitmap and a Metafile picture.

          [1mBackground... [22msets the window background color.










GNUPLOT 4.1                                                      290


          [1mChoose Font... [22mselects the font used in the graphics win-
          dow.

          [1mLine Styles... [22mallows customization of the line colors and
          styles.

          [1mPrint... [22mprints the graphics windows using a Windows
          printer driver and allows selection of the printer and
          scaling of the output.  The output produced by [1mPrint [22mis
          not as good as that from [1mgnuplot[22m's own printer drivers.

          [1mUpdate wgnuplot.ini [22msaves the current window locations,
          window sizes, text window font, text window font size,
          graph window font, graph window font size, background
          color and linestyles to the initialization file [1mWGNU-[0m
          [1mPLOT.INI[22m.



          [1m53.75.2.  Printing[0m


          In order of preference, graphs may be be printed in the
          following ways.

          [1m1. [22mUse the [1mgnuplot [22mcommand [1mset terminal [22mto select a
          printer and [1mset output [22mto redirect output to a file.

          [1m2. [22mSelect the [1mPrint... [22mcommand from the [1mgnuplot graph [22mwin-
          dow.  An extra command [1mscreendump [22mdoes this from the text
          window.

          [1m3. [22mIf [1mset output "PRN" [22mis used, output will go to a tempo-
          rary file.  When you exit from [1mgnuplot [22mor when you change
          the output with another [1mset output [22mcommand, a dialog box
          will appear for you to select a printer port.  If you
          choose OK, the output will be printed on the selected
          port, passing unmodified through the print manager.  It is
          possible to accidentally (or deliberately) send printer
          output meant for one printer to an incompatible printer.



          [1m53.75.3.  Text-menu[0m


          The [1mgnuplot text [22mwindow has the following options on a
          pop-up menu accessed by pressing the right mouse button or
          selecting [1mOptions [22mfrom the system menu:

          [1mCopy to Clipboard [22mcopies marked text to the clipboard.

          [1mPaste [22mcopies text from the clipboard as if typed by the










GNUPLOT 4.1                                                      291


          user.

          [1mChoose Font... [22mselects the font used in the text window.

          [1mSystem Colors [22mwhen selected makes the text window honor
          the System Colors set using the Control Panel.  When unse-
          lected, text is black or blue on a white background.

          [1mUpdate wgnuplot.ini [22msaves the current text window loca-
          tion, text window size, text window font and text window
          font size to the initialisation file [1mWGNUPLOT.INI[22m.

          [1mMENU BAR[0m

          If the menu file [1mWGNUPLOT.MNU [22mis found in the same direc-
          tory as WGNUPLOT.EXE, then the menu specified in [1mWGNU-[0m
          [1mPLOT.MNU [22mwill be loaded.  Menu commands:

          [Menu] starts a new menu with the name on the following
          line.

          [EndMenu] ends the current menu.

          [--] inserts a horizontal menu separator.

          [|] inserts a vertical menu separator.

          [Button] puts the next macro on a push button instead of a
          menu.

          Macros take two lines with the macro name (menu entry) on
          the first line and the macro on the second line.  Leading
          spaces are ignored.  Macro commands:

          [INPUT] --- Input string with prompt terminated by [EOS]
          or {ENTER}

          [EOS] --- End Of String terminator.  Generates no output.

          [OPEN] --- Get name of file to open from list box, with
          title of list box terminated by [EOS], followed by default
          filename terminated by [EOS] or {ENTER}.  This uses COM-
          MDLG.DLL from Windows 3.1.

          [SAVE] --- Get name of file to save.  Similar to [OPEN]

          Macro character substitutions:

          {ENTER} --- Carriage Return '\r'

          {TAB} --- Tab '\011'

          {ESC} --- Escape '\033'










GNUPLOT 4.1                                                      292


          {^A} --- '\001'

          ...

          {^_} --- '\031'

          Macros are limited to 256 characters after expansion.



          [1m53.75.4.  Wgnuplot.ini[0m


          Windows [1mgnuplot [22mwill read some of its options from the
          [1m[WGNUPLOT] [22msection of [1mWGNUPLOT.INI [22min the Windows direc-
          tory.  A sample [1mWGNUPLOT.INI [22mfile:

                [WGNUPLOT]
                TextOrigin=0 0
                TextSize=640 150
                TextFont=Terminal,9
                GraphOrigin=0 150
                GraphSize=640 330
                GraphFont=Arial,10
                GraphColor=1
                GraphToTop=1
                GraphBackground=255 255 255
                Border=0 0 0 0 0
                Axis=192 192 192 2 2
                Line1=0 0 255 0 0
                Line2=0 255 0 0 1
                Line3=255 0 0 0 2
                Line4=255 0 255 0 3
                Line5=0 0 128 0 4

          The [1mGraphFont [22mentry specifies the font name and size in
          points.  The five numbers given in the [1mBorder[22m, [1mAxis [22mand
          [1mLine [22mentries are the [1mRed [22mintensity (0--255), [1mGreen [22minten-
          sity, [1mBlue [22mintensity, [1mColor Linestyle [22mand [1mMono Linestyle[22m.
          [1mLinestyles [22mare 0=SOLID, 1=DASH, 2=DOT, 3=DASHDOT, 4=DASH-
          DOTDOT.  In the sample [1mWGNUPLOT.INI [22mfile above, Line 2 is
          a green solid line in color mode, or a dashed line in
          monochrome mode.  The default line width is 1 pixel.  If
          [1mLinestyle [22mis negative, it specifies the width of a SOLID
          line in pixels.  Line1 and any linestyle used with the
          [1mpoints [22mstyle must be SOLID with unit width.



          [1m53.75.5.  Windows3.0[0m













GNUPLOT 4.1                                                      293


          Windows 3.1 is preferred, but WGNUPLOT will run under Win-
          dows 3.0 with the following restrictions: [1m1. [22mCOMMDLG.DLL
          and SHELL.DLL (available with Windows 3.1 or Borland C++
          3.1) must be in the windows directory.

          [1m2. [22mWGNUPLOT.HLP produced by Borland C++ 3.1 is in Windows
          3.1 format.  You need to use the WINHELP.EXE supplied with
          Borland C++ 3.1.

          [1m3. [22mIt will not run in real mode due to lack of memory.

          [1m4. [22mTrueType fonts are not available in the graph window.

          [1m5. [22mDrag-drop does not work.



     [1m53.76.  Wxt[0m


     The [1mwxt [22mterminal device generates output in a separate window.
     The window is created by the wxWidgets library, where the 'wxt'
     comes from. The actual drawing is done via cairo, a 2D graphics
     library, and pango, a library for laying out and rendering
     text.

     Syntax:
             set term wxt {<n>}
                          {{no}enhanced}
                          {font <font>}
                          {title "title"}
                          {{no}persist}
                          {{no}raise}
                          {{no}ctrl}
                          {close}

     Multiple plot windows are supported: [1mset terminal wxt <n>[0m
     directs the output to plot window number n.

     The default window title is based on the window number. This
     title can also be specified with the keyword "title".

     Plot windows remain open even when the [1mgnuplot [22mdriver is
     changed to a different device.  A plot window can be closed by
     pressing the letter 'q' while that window has input focus, by
     choosing [1mclose [22mfrom a window manager menu, or with [1mset term wxt[0m
     [1m<n> close[22m.

     When you resize a window, the plot is immediately scaled to fit
     in the new size of the window. Unlike other interactive termi-
     nals, the [1mwxt [22mterminal scales the whole plot, including fonts
     and linewidths, and keeps its global aspect ratio constant,
     leaving an empty space painted in gray.  If you type [1mreplot[22m,










GNUPLOT 4.1                                                      294


     click the [1mreplot [22micon in the terminal toolbar or type a new
     [1mplot [22mcommand, the new plot will completely fit in the window
     and the font size and the linewidths will be reset to their
     defaults.

     The active plot window (the one selected by [1mset term wxt <n>[22m)
     is interactive. Its behaviour is shared with other terminal
     types. See [1mmouse [22mfor details. It also has some extra icons,
     which are supposed to be self-explanatory.

     This terminal supports an enhanced text mode, which allows font
     and other formatting commands (subscripts, superscripts, etc.)
     to be embedded in labels and other text strings. The enhanced
     text mode syntax is shared with other gnuplot terminal types.
     See [1menhanced [22mfor more details.

     <font> is in the format "FontFace,FontSize", i.e. the face and
     the size comma-separated in a single string. FontFace is a
     usual font face name, such as 'Arial'. If you do not provide
     FontFace, the wxt terminal will use 'Sans'. FontSize is the
     font size, in points. If you do not provide it, the wxt termi-
     nal will use a size of 10 points.
        For example :
           set term wxt font "Arial,12"
           set term wxt font "Arial" # to change the font face only
           set term wxt font ",12" # to change the font size only
           set term wxt font "" # to reset the font name and size

     The fonts are retrieved from the usual fonts subsystems. Under
     Windows, those fonts are to be found and configured in the
     entry "Fonts" of the control panel. Under UNIX, they are han-
     dled by "fontconfig".

     Pango, the library used to layout the text, is based on utf-8.
     Thus, the wxt terminal has to convert from your encoding to
     utf-8. The default input encoding is based on your 'locale'. If
     you want to use another encoding, make sure gnuplot knows which
     one you are using. See [1mencoding [22mfor more details.

     Pango may give unexpected results with fonts that do not
     respect the unicode mapping. With the Symbol font, for example,
     the wxt terminal will use the map provided by http://www.uni-
     code.org/ to translate character codes to unicode.  Pango will
     do its best to find a font containing this character, looking
     for your Symbol font, or other fonts with a broad unicode cov-
     erage, like the DejaVu fonts. Note that "the Symbol font" is to
     be understood as the Adobe Symbol font, distributed with Acro-
     bat Reader as "SY______.PFB".  Alternatively, the OpenSymbol
     font, distributed with OpenOffice.org as "opens___.ttf", offers
     the same characters. Microsoft has distributed a Symbol font
     ("symbol.ttf"), but it has a different character set with sev-
     eral missing or moved mathematic characters. If you experience
     problems with your default setup (if the demo enhancedtext.dem










GNUPLOT 4.1                                                      295


     is not displayed properly for example), you probably have to
     install one of the Adobe or OpenOffice Symbol fonts, and remove
     the Microsoft one.  Other non-conform fonts, such as
     "wingdings" have been observed working.

     The rendering of the plot can be altered with a dialog avail-
     able from the toolbar. To obtain the best output possible, the
     rendering involves three mechanisms : antialiasing, oversam-
     pling and hinting.  Antialiasing allows to display non-horizon-
     tal and non-vertical lines smoother.  Oversampling combined
     with antialiasing provides subpixel accuracy, so that gnuplot
     can draw a line from non-integer coordinates. This avoids wob-
     bling effects on diagonal lines ('plot x' for example).  Hint-
     ing avoids the blur on horizontal and vertical lines caused by
     oversampling. The terminal will snap these lines to integer
     coordinates so that a one-pixel-wide line will actually be
     drawn on one and only one pixel.

     By default, the window is raised to the top of your desktop
     when a plot is drawn. This can be controlled with the keyword
     "raise".  The keyword "persist" will prevent gnuplot from exit-
     ing before you explicitely close all the plot windows.
     Finally, by default the key <space> raises the gnuplot console
     window, and 'q' closes the plot window. The keyword "ctrl"
     allows you to replace those bindings by <ctrl>+<space> and
     <ctrl>+'q', respectively.  These three keywords (raise, persist
     and ctrl) can also be set and remembered between sessions
     through the configuration dialog.



     [1m53.77.  X11[0m


     [1mgnuplot [22mprovides the [1mx11 [22mterminal type for use with X servers.
     This terminal type is set automatically at startup if the [1mDIS-[0m
     [1mPLAY [22menvironment variable is set, if the [1mTERM [22menvironment vari-
     able is set to [1mxterm[22m, or if the [1m-display [22mcommand line option is
     used.

     Syntax:
        set terminal x11 {<n>}
                         {title "<string>"}
                         {{no}enhanced}
                         {font <fontspec>}
                         {{no}persist} {{no}raise} {solid|dashed}
     {{no}ctrlq}
                         {close}
        set terminal x11 {reset}

     Multiple plot windows are supported: [1mset terminal x11 <n>[0m
     directs the output to plot window number n.  If n is not 0, the
     terminal number will be appended to the window title (unless a










GNUPLOT 4.1                                                      296


     title has been supplied manually) and the icon will be labeled
     [1mGnuplot <n>[22m.  The active window may be distinguished by a
     change in cursor (from default to crosshair).

     The x11 terminal support enhanced text mode (see [1menhanced[22m),
     subject to the available fonts. In order for font size commands
     embedded in text to have any effect, the default x11 font must
     be scalable. Thus the first example below will work as
     expected, but the second will not.

        set term x11 enhanced font "arial,15"
        set title '{/=20 Big} Medium {/=5 Small}'

        set term x11 enhanced font "terminal-14"
        set title '{/=20 Big} Medium {/=5 Small}'

     Plot windows remain open even when the [1mgnuplot [22mdriver is
     changed to a different device.  A plot window can be closed by
     pressing the letter q while that window has input focus, or by
     choosing [1mclose [22mfrom a window manager menu.  All plot windows
     can be closed by specifying [1mreset[22m, which actually terminates
     the subprocess which maintains the windows (unless [1m-persist [22mwas
     specified).  The [1mclose [22mcommand can be used to close individual
     plot windows by number.  However, after a [1mreset[22m, those plot
     windows left due to persist cannot be closed with the command
     [1mclose[22m.  A [1mclose [22mwithout a number closes the current active plot
     window.

     The gnuplot outboard driver, gnuplot_x11, is searched in a
     default place chosen when the program is compiled.  You can
     override that by defining the environment variable GNU-
     PLOT_DRIVER_DIR to point to a different location.

     Plot windows will automatically be closed at the end of the
     session unless the [1m-persist [22moption was given.

     The options [1mpersist [22mand [1mraise [22mare unset by default, which means
     that the defaults (persist == no and raise == yes) or the com-
     mand line options -persist / -raise or the Xresources are
     taken.  If [no]persist or [no]raise are specified, they will
     override command line options and Xresources.  Setting one of
     these options takes place immediately, so the behaviour of an
     already running driver can be modified.  If the window does not
     get raised, see discussion in [1mraise[22m.

     The option [1mtitle "<title name>" [22mwill supply the title name of
     the window for the current plot window or plot window <n> if a
     number is given.  Where (or if) this title is shown depends on
     your X window manager.

     The size or aspect ratio of a plot may be changed by resizing
     the [1mgnuplot [22mwindow.











GNUPLOT 4.1                                                      297


     Linewidths and pointsizes may be changed from within [1mgnuplot[0m
     with [1mset linestyle[22m.

     For terminal type [1mx11[22m, [1mgnuplot [22maccepts (when initialized) the
     standard X Toolkit options and resources such as geometry,
     font, and name from the command line arguments or a configura-
     tion file.  See the X(1) man page (or its equivalent) for a
     description of such options.

     A number of other [1mgnuplot [22moptions are available for the [1mx11[0m
     terminal.  These may be specified either as command-line
     options when [1mgnuplot [22mis invoked or as resources in the configu-
     ration file ".Xdefaults".  They are set upon initialization and
     cannot be altered during a [1mgnuplot [22msession.  (except [1mpersist[0m
     and [1mraise[22m)




          [1m53.77.1.  X11_fonts[0m


          Upon initial startup, the default font is taken from the
          X11 resources as set in the system or user .Xdefaults file
          or on the command line.

          Example:
                gnuplot*font: lucidasans-bold-12
          A new default font may be specified to the x11 driver from
          inside gnuplot using
               `set term x11 font "<fontspec>"`
          The driver first queries the X-server for a font of the
          exact name given.  If this query fails, then it tries to
          interpret <fontspec> as "<font>,<size>,<slant>,<weight>"
          and to construct a full X11 font name of the form
                -*-<font>-<weight>-<s>-*-*-<size>-*-*-*-*-*-<encod-
          ing>

           <font> is the base name of the font (e.g. Times or Sym-
          bol)
           <size> is the point size (defaults to 12 if not speci-
          fied)
           <s> is `i` if <slant>=="italic" `o` if <slant>=="oblique"
          `r` otherwise
           <weight> is `medium` or `bold` if explicitly requested,
          otherwise `*`
           <encoding> is set based on the current character set (see
          `set encoding`).
          So [1mset term x11 font "arial,15,italic" [22mwill be translated
          to -*-arial-*-i-*-*-15-*-*-*-*-*-iso8859-1 (assuming
          default encoding).  The <size>, <slant>, and <weight>
          specifications are all optional.  If you do not specify
          <slant> or <weight> then you will get whatever font










GNUPLOT 4.1                                                      298


          variant the font server offers first.  You may set a
          default enconding via the corresponding X11 resource. E.g.
                gnuplot*encoding: iso8859-15
          The driver also recognizes some common PostScript font
          names and replaces them with possible X11 or TrueType
          equivalents.  This same sequence is used to process font
          requests from [1mset label[22m.

          If your gnuplot was built with configuration option
          --enable-x11-mbfonts, you can specify multi-byte fonts by
          using the prefix "mbfont:" on the font name. An additional
          font may be given, separated by a semicolon.  Since multi-
          byte font encodings are interpreted according to the
          locale setting, you must make sure that the environmental
          variable LC_CTYPE is set to some appropriate locale value
          such as ja_JP.eucJP, ko_KR.EUC, or zh_CN.EUC.

          Example:
                set term x11 font 'mbfont:kana14;k14'
                      # 'kana14' and 'k14' are Japanese X11 font
          aliases, and ';'
                      # is the separator of font names.
                set term x11 font 'mbfont:fixed,16,r,medium'
                      # <font>,<size>,<slant>,<weight> form is also
          usable.
                set title '(mb strings)' font 'mbfont:*-fixed-
          medium-r-normal--14-*'

          The same syntax applies to the default font in Xresources
          settings, for example,
                gnuplot*font: \
                    mbfont:-misc-fixed-medium-r-nor-
          mal--14-*-*-*-c-*-jisx0208.1983-0

          If gnuplot is built with --enable-x11-mbfonts, you can use
          two special PostScript font names 'Ryumin-Light-*' and
          'GothicBBB-Medium-*' (standard Japanese PS fonts) without
          the prefix "mbfont:".




          [1m53.77.2.  Command-line_options[0m


          In addition to the X Toolkit options, the following
          options may be specified on the command line when starting
          [1mgnuplot [22mor as resources in your ".Xdefaults" file (note
          that [1mraise [22mand [1mpersist [22mcan be overridden later by [1mset term[0m
          [1mx11 [no]raise [no]persist)[22m:













GNUPLOT 4.1                                                      299


+-----------------------------------------------------------------------------+
|  `-mono`      forces monochrome rendering on color displays.                |
|  `-gray`      requests grayscale rendering on grayscale or color displays.  |
|               (Grayscale displays receive monochrome rendering by default.) |
|  `-clear`     requests that the window be cleared momentarily before a      |
|               new plot is displayed.                                        |
|  `-tvtwm`     requests that geometry specifications for position of the     |
|               window be made relative to the currently displayed portion    |
|               of the virtual root.                                          |
|  `-raise`     raises plot window after each plot                            |
| `-noraise`    does not raise plot window after each plot                    |
|`-novevents`   does not process mouse and key events                         |
|  `-ctrlq`     closes window on ctrl-q rather than q                         |
| `-persist`    plot windows survive after main gnuplot program exits         |
+-----------------------------------------------------------------------------+


The options are shown above in their command-line syntax.  When
entered as resources in ".Xdefaults", they require a different syn-
tax.

Example:
      gnuplot*gray:  on
      gnuplot*ctrlq: on

[1mgnuplot [22malso provides a command line option ([1m-pointsize <v>[22m) and a
resource, [1mgnuplot*pointsize: <v>[22m, to control the size of points
plotted with the [1mpoints [22mplotting style.  The value [1mv [22mis a real num-
ber (greater than 0 and less than or equal to ten) used as a scaling
factor for point sizes.  For example, [1m-pointsize 2 [22muses points twice
the default size, and [1m-pointsize 0.5 [22muses points half the normal
size.

The [1m-noevents [22mswitch disables all mouse and key event processing
(except for [1mq [22mand [1m<space> [22mfor closing the window). This is useful
for programs which use the x11 driver independent of the gnuplot
main program.

The [1m-ctrlq [22mswitch changes the hot-key that closes a plot window from
[1mq [22mto [1m<ctrl>q[22m. This is useful is you are using the keystroke-capture
feature [1mpause mouse keystroke[22m, since it allows the character [1mq [22mto be
captured just as all other alphanumeric characters. The [1m-ctrlq[0m
switch similarly replaces the <space> hot-key with <ctrl><space> for
the same reason.




          [1m53.77.3.  Monochrome_options[0m


          For monochrome displays, [1mgnuplot [22mdoes not honor foreground
          or background colors.  The default is black-on-white.  [1m-rv[0m










GNUPLOT 4.1                                                      300


          or [1mgnuplot*reverseVideo: on [22mrequests white-on-black.




          [1m53.77.4.  Color_resources[0m


          For color displays, [1mgnuplot [22mhonors the following resources
          (shown here with their default values) or the greyscale
          resources.  The values may be color names as listed in the
          X11 rgb.txt file on your system, hexadecimal RGB color
          specifications (see X11 documentation), or a color name
          followed by a comma and an [1mintensity [22mvalue from 0 to 1.
          For example, [1mblue, 0.5 [22mmeans a half intensity blue.



                 +--------------------------------+
                 |    gnuplot*background: white   |
                 |    gnuplot*textColor: black    |
                 |    gnuplot*borderColor: black  |
                 |    gnuplot*axisColor: black    |
                 |    gnuplot*line1Color: red     |
                 |    gnuplot*line2Color: green   |
                 |    gnuplot*line3Color: blue    |
                 |    gnuplot*line4Color: magenta |
                 |    gnuplot*line5Color: cyan    |
                 |    gnuplot*line6Color: sienna  |
                 |    gnuplot*line7Color: orange  |
                 |    gnuplot*line8Color: coral   |
                 +--------------------------------+



The command-line syntax for these is simple only for background,
which maps directly to the usual X11 toolkit option "-bg".  All oth-
ers can only be set on the command line by use of the generic "-xrm"
resource override option

Examples:

      gnuplot -background coral
to change the background color.

      gnuplot -xrm 'gnuplot*line1Color:blue'
to override the first linetype color.
















GNUPLOT 4.1                                                      301


          [1m53.77.5.  Grayscale_resources[0m


          When [1m-gray [22mis selected, [1mgnuplot [22mhonors the following
          resources for grayscale or color displays (shown here with
          their default values).  Note that the default background
          is black.



                  +-------------------------------+
                  |    gnuplot*background: black  |
                  |    gnuplot*textGray: white    |
                  |    gnuplot*borderGray: gray50 |
                  |    gnuplot*axisGray: gray50   |
                  |    gnuplot*line1Gray: gray100 |
                  |    gnuplot*line2Gray: gray60  |
                  |    gnuplot*line3Gray: gray80  |
                  |    gnuplot*line4Gray: gray40  |
                  |    gnuplot*line5Gray: gray90  |
                  |    gnuplot*line6Gray: gray50  |
                  |    gnuplot*line7Gray: gray70  |
                  |    gnuplot*line8Gray: gray30  |
                  +-------------------------------+






          [1m53.77.6.  Line_resources[0m


          [1mgnuplot [22mhonors the following resources for setting the
          width (in pixels) of plot lines (shown here with their
          default values.)  0 or 1 means a minimal width line of 1
          pixel width.  A value of 2 or 3 may improve the appearance
          of some plots.

























GNUPLOT 4.1                                                      302


                    +---------------------------+
                    |    gnuplot*borderWidth: 2 |
                    |    gnuplot*axisWidth: 0   |
                    |    gnuplot*line1Width: 0  |
                    |    gnuplot*line2Width: 0  |
                    |    gnuplot*line3Width: 0  |
                    |    gnuplot*line4Width: 0  |
                    |    gnuplot*line5Width: 0  |
                    |    gnuplot*line6Width: 0  |
                    |    gnuplot*line7Width: 0  |
                    |    gnuplot*line8Width: 0  |
                    +---------------------------+



[1mgnuplot [22mhonors the following resources for setting the dash style
used for plotting lines.  0 means a solid line.  A two-digit number
[1mjk [22m([1mj [22mand [1mk [22mare >= 1 and <= 9) means a dashed line with a repeated
pattern of [1mj [22mpixels on followed by [1mk [22mpixels off.  For example, '16'
is a dotted line with one pixel on followed by six pixels off.  More
elaborate on/off patterns can be specified with a four-digit value.
For example, '4441' is four on, four off, four on, one off.  The
default values shown below are for monochrome displays or monochrome
rendering on color or grayscale displays.  Color displays default to
dashed:off



                  +------------------------------+
                  |    gnuplot*dashed: off       |
                  |    gnuplot*borderDashes: 0   |
                  |    gnuplot*axisDashes: 16    |
                  |    gnuplot*line1Dashes: 0    |
                  |    gnuplot*line2Dashes: 42   |
                  |    gnuplot*line3Dashes: 13   |
                  |    gnuplot*line4Dashes: 44   |
                  |    gnuplot*line5Dashes: 15   |
                  |    gnuplot*line6Dashes: 4441 |
                  |    gnuplot*line7Dashes: 42   |
                  |    gnuplot*line8Dashes: 13   |
                  +------------------------------+






          [1m53.77.7.  X11 pm3d_resources[0m


          Choosing the appropriate visual class and number of colors
          is a crucial point in X11 applications and a bit awkward,
          since X11 supports six visual types in different depths.










GNUPLOT 4.1                                                      303


          By default [1mgnuplot [22muses the default visual of the screen.
          The number of colors which can be allocated depends on the
          visual class chosen. On a visual class with a depth >
          12bit, gnuplot starts with a maximal number of 0x200 col-
          ors.  On a visual class with a depth > 8bit (but <= 12
          bit) the maximal number of colors is 0x100, on <= 8bit
          displays the maximum number of colors is 240 (16 are left
          for line colors).

          Gnuplot first starts to allocate the maximal number of
          colors as stated above.  If this fails, the number of col-
          ors is reduced by the factor 2 until gnuplot gets all col-
          ors which are requested. If dividing [1mmaxcolors [22mby 2
          repeatedly results in a number which is smaller than [1mmin-[0m
          [1mcolors gnuplot [22mtries to install a private colormap. In
          this case the window manager is responsible for swapping
          colormaps when the pointer is moved in and out the x11
          driver's window.

          The default for [1mmincolors [22mis maxcolors / (num_colormaps >
          1 ? 2 : 8), where num_colormaps is the number of colormaps
          which are currently used by gnuplot (usually 1, if only
          one x11 window is open).

          Some systems support multiple (different) visual classes
          together on one screen. On these systems it might be nec-
          essary to force gnuplot to use a specific visual class,
          e.g. the default visual might be 8bit PseudoColor but the
          screen would also support 24bit TrueColor which would be
          the preferred choice.

          The information about an Xserver's capabilities can be
          obtained with the program [1mxdpyinfo[22m.  For the visual names
          below you can choose one of StaticGray, GrayScale, Static-
          Color, PseudoColor, TrueColor, DirectColor.  If an Xserver
          supports a requested visual type at different depths, [1mgnu-[0m
          [1mplot [22mchooses the visual class with the highest depth
          (deepest).  If the requested visual class matches the
          default visual and multiple classes of this type are sup-
          ported, the default visual is preferred.

          Example: on an 8bit PseudoColor visual you can force a
          private color map by specifying [1mgnuplot*maxcolors: 240 [22mand
          [1mgnuplot*mincolors: 240[22m.



















GNUPLOT 4.1                                                      304


             +-----------------------------------------+
             |    gnuplot*maxcolors:  <integer number> |
             |    gnuplot*mincolors:  <integer number> |
             |    gnuplot*visual:     <visual name>    |
             +-----------------------------------------+






          [1m53.77.8.  X11 other_resources[0m


          By default the contents of the current plot window are
          exported to the X11 clipboard in response to X events in
          the window. Setting the resource 'gnuplot*exportselection'
          to 'off' or 'false' will disable this.

          By default text rotation is done using a method that is
          fast, but can corrupt nearby colors depending on the back-
          ground.  If this is a problem, you can set the resource
          'gnuplot.fastrotate' to 'off'




                +----------------------------------+
                |    gnuplot*exportselection:  off |
                |    gnuplot*fastrotate:  on       |
                |    gnuplot*ctrlq:  off           |
                +----------------------------------+





     [1m53.78.  Xlib[0m


     The [1mxlib [22mterminal driver supports the X11 Windows System.  It
     generates gnuplot_x11 commands, but sends them to the output
     file specified by [1mset output '<filename>'[22m. [1mset term x11 [22mis
     equivalent to [1mset terminal xlib; set output "|gnuplot_x11[0m
     [1m-noevents"[22m.  [1mxlib [22mtakes the same set of options as [1mx11[22m.




     [1m54.  Graphical User Interfaces[0m













GNUPLOT 4.1                                                      305


     Several graphical user interfaces have been written for [1mgnuplot[0m
     and one for win32 is included in this distribution.  In addi-
     tion, there is a Python interface at
              http://py-gnuplot.darwinports.com/

     Also several X11 interfaces exist.  One of them is called xgfe.
     It uses the Qt library and can be found on
              http://www.flash.net/~dmishee/xgfe/xgfe.html

     In addition three Tcl/Tk located at the usual Tcl/Tk reposito-
     ries exist.

     Bruce Ravel (ravel@phys.washington.edu) has written a new ver-
     sion of gnuplot-mode for GNU emacs and XEmacs. This version is
     based on the gnuplot.el file by Gershon Elber.  While the gnu-
     plot CVS repository has its own copy the most recent version of
     this package is available from
               http://feff.phys.washington.edu/~ravel/software/gnu-
     plot-mode/





     [1m55.  Bugs[0m


     Bugs reported since the current release as well as older ones
     may be located via the official distribution site on Source-
     Forge.

     Please e-mail bug reports to the gnuplot-bugs mailing list.  Or
     upload the report to the gnuplot web site on SourceForge.
     Please give complete information on the version of gnuplot you
     are using and, if possible, a test script that demonstrates the
     bug.  See [1mSeeking-assistance[22m.

     The sections below list problems known to be present in gnuplot
     version 4.2 at the time of release.  Some of these are actually
     bugs in external support libraries and may have been fixed
     indepently of any changes in gnuplot.




     [1m56.  Gnuplot limitations[0m


     Floating point exceptions (floating point number too
     large/small, divide by zero, etc.) may occasionally be gener-
     ated by user defined functions.  Some of the demos in particu-
     lar may cause numbers to exceed the floating point range.
     Whether the system ignores such exceptions (in which case










GNUPLOT 4.1                                                      306


     [1mgnuplot [22mlabels the corresponding point as undefined) or aborts
     [1mgnuplot [22mdepends on the compiler/runtime environment.

     The gamma and bessel functions do not work for complex argu-
     ments.

     If a command line contains a "load" command, then anything on
     the line after the "load <filename>" is ignored.

     Only one color palette at a time is active for any given x11
     plot window.  This means that multiplots whose constituent
     plots use different palettes will not display correctly in x11.

     Coordinates specified as "time" wrap at 24 hours, and have a
     precision limited to 1 second.  This is in particular a limita-
     tion in using time format to handle geographic coordinates.

     Error bars are not handled properly in polar/spherical coordi-
     nate plot modes.

     The 'nohidden3d' option that is supposed to exempt individual
     plots from the global property 'set hidden3d' does not work for
     parametric curves.




     [1m57.  Specific terminals[0m


     Some older models of HP plotters do not have a page eject com-
     mand 'PG'.  The current HPGL driver uses this command in
     HPGL_reset.  This may need to be removed for these plotters.
     The current PCL5 driver uses HPGL/2 for text as well as graph-
     ics.  This should be modified to use scalable PCL fonts.




     [1m58.  External libraries[0m


     External library GD (used by PNG/JPEG/GIF drivers): Versions of
     libgd through 2.0.33 contain various bugs in mapping the char-
     acters of Adobe's Symbol font.  Also it is possible to trigger
     a library segfault if an anti-aliased line crosses an upper
     corner of the canvas.

     External library PDFlib (used by PDF driver): Gnuplot can be
     linked against libpdf versions 4, 5, or 6. However, these ver-
     sions differ in their handling of piped I/O.  Therefore gnuplot
     scripts using piped output to PDF may work only for some ver-
     sions of PDFlib.










GNUPLOT 4.1                                                      307


     External library svgalib (used by linux and vgagl driver):
     Requires gnuplot to be suid root (bad!) and has many bugs that
     are specific to the video card or graphics driver used in X11.

     Internationalization (locale settings): Gnuplot uses the C run-
     time library routine setlocale() to control locale-specific
     formatting of input and output number, times, and date strings.
     The locales available, and the level of support for locale fea-
     tures such as "thousands' grouping separator", depend on the
     internationalization support provided by your individual
     machine.




















































GNUPLOT 4.1                                                        i


                            [1mTable of Contents[0m


     Gnuplot . . . . . . . . . . . . . . . . . . . . . . . . . .   1
     Copyright . . . . . . . . . . . . . . . . . . . . . . . . .   1
     Introduction  . . . . . . . . . . . . . . . . . . . . . . .   2
     Seeking-assistance  . . . . . . . . . . . . . . . . . . . .   3
     New features introduced in version 4.2  . . . . . . . . . .   4
     New plot styles . . . . . . . . . . . . . . . . . . . . . .   4
     Histogram . . . . . . . . . . . . . . . . . . . . . . . . .   4
     Label plots . . . . . . . . . . . . . . . . . . . . . . . .   4
     Image data  . . . . . . . . . . . . . . . . . . . . . . . .   5
     Filled curves . . . . . . . . . . . . . . . . . . . . . . .   5
     Vectors . . . . . . . . . . . . . . . . . . . . . . . . . .   5
     Input from binary data files  . . . . . . . . . . . . . . .   5
     New plot elements . . . . . . . . . . . . . . . . . . . . .   5
     RGB colors  . . . . . . . . . . . . . . . . . . . . . . . .   6
     Arbitrary rectangles  . . . . . . . . . . . . . . . . . . .   6
     String handling . . . . . . . . . . . . . . . . . . . . . .   6
     String and text data read from datafiles  . . . . . . . . .   6
     User-defined string variables, operators, and functions . .   6
     Macros  . . . . . . . . . . . . . . . . . . . . . . . . . .   6
     Auto-layout of multiple plots on a page . . . . . . . . . .   7
     Internal variables  . . . . . . . . . . . . . . . . . . . .   7
     New or revised terminal drivers . . . . . . . . . . . . . .   7
     `wxt` . . . . . . . . . . . . . . . . . . . . . . . . . . .   7
     `emf` . . . . . . . . . . . . . . . . . . . . . . . . . . .   7
     `gif`, `jpeg`, `png`  . . . . . . . . . . . . . . . . . . .   7
     `postscript`  . . . . . . . . . . . . . . . . . . . . . . .   8
     `ai`  . . . . . . . . . . . . . . . . . . . . . . . . . . .   8
     `epslatex`, `pslatex`, `pstex`  . . . . . . . . . . . . . .   8
     `windows` . . . . . . . . . . . . . . . . . . . . . . . . .   8
     Canvas size . . . . . . . . . . . . . . . . . . . . . . . .   8
     Backwards compatibility . . . . . . . . . . . . . . . . . .   9
     Features introduced in version 4.0  . . . . . . . . . . . .  10
     Mouse and hotkey support in interactive terminals . . . . .  10
     New terminals . . . . . . . . . . . . . . . . . . . . . . .  10
     New plot style `pm3d` . . . . . . . . . . . . . . . . . . .  11
     Filled boxes  . . . . . . . . . . . . . . . . . . . . . . .  11
     New plot option smooth frequency  . . . . . . . . . . . . .  11
     Improved text options . . . . . . . . . . . . . . . . . . .  12
     More text encodings . . . . . . . . . . . . . . . . . . . .  12
     Arrows  . . . . . . . . . . . . . . . . . . . . . . . . . .  12
     Data file format  . . . . . . . . . . . . . . . . . . . . .  13
     New commands  . . . . . . . . . . . . . . . . . . . . . . .  13
     Other changes and additions . . . . . . . . . . . . . . . .  13
     Accompanying documentation  . . . . . . . . . . . . . . . .  14
     Batch/Interactive Operation . . . . . . . . . . . . . . . .  14
     Command-line-editing  . . . . . . . . . . . . . . . . . . .  15
     Comments  . . . . . . . . . . . . . . . . . . . . . . . . .  16
     Coordinates . . . . . . . . . . . . . . . . . . . . . . . .  17
     Datastrings . . . . . . . . . . . . . . . . . . . . . . . .  17
     Environment . . . . . . . . . . . . . . . . . . . . . . . .  18










GNUPLOT 4.1                                                       ii


     Expressions . . . . . . . . . . . . . . . . . . . . . . . .  20
     Functions . . . . . . . . . . . . . . . . . . . . . . . . .  21
     Random number generator . . . . . . . . . . . . . . . . . .  23
     Operators . . . . . . . . . . . . . . . . . . . . . . . . .  24
     Unary . . . . . . . . . . . . . . . . . . . . . . . . . . .  24
     Binary  . . . . . . . . . . . . . . . . . . . . . . . . . .  25
     Ternary . . . . . . . . . . . . . . . . . . . . . . . . . .  26
     Gnuplot-defined variables . . . . . . . . . . . . . . . . .  27
     User-defined variables and functions  . . . . . . . . . . .  27
     Glossary  . . . . . . . . . . . . . . . . . . . . . . . . .  28
     Linetype, colors, and styles  . . . . . . . . . . . . . . .  29
     Colorspec . . . . . . . . . . . . . . . . . . . . . . . . .  31
     Mouse input . . . . . . . . . . . . . . . . . . . . . . . .  32
     Bind  . . . . . . . . . . . . . . . . . . . . . . . . . . .  32
     Mouse variables . . . . . . . . . . . . . . . . . . . . . .  34
     Plotting  . . . . . . . . . . . . . . . . . . . . . . . . .  35
     Start-up  . . . . . . . . . . . . . . . . . . . . . . . . .  35
     String constants and string variables . . . . . . . . . . .  36
     Substitution and Command line macros  . . . . . . . . . . .  37
     Substitution of system commands in backquotes . . . . . . .  37
     Substitution of string variables as macros  . . . . . . . .  38
     String variables, macros, and command line substitution . .  38
     Syntax  . . . . . . . . . . . . . . . . . . . . . . . . . .  39
     Quote Marks . . . . . . . . . . . . . . . . . . . . . . . .  40
     Time/Date data  . . . . . . . . . . . . . . . . . . . . . .  41
     Commands  . . . . . . . . . . . . . . . . . . . . . . . . .  42
     Cd  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  42
     Call  . . . . . . . . . . . . . . . . . . . . . . . . . . .  43
     Clear . . . . . . . . . . . . . . . . . . . . . . . . . . .  44
     Exit  . . . . . . . . . . . . . . . . . . . . . . . . . . .  44
     Fit . . . . . . . . . . . . . . . . . . . . . . . . . . . .  45
     Adjustable parameters . . . . . . . . . . . . . . . . . . .  46
     Short introduction  . . . . . . . . . . . . . . . . . . . .  47
     Error estimates . . . . . . . . . . . . . . . . . . . . . .  48
     Statistical overview  . . . . . . . . . . . . . . . . . . .  49
     Practical guidelines  . . . . . . . . . . . . . . . . . . .  50
     Control . . . . . . . . . . . . . . . . . . . . . . . . . .  52
     Control variables . . . . . . . . . . . . . . . . . . . . .  52
     Environment variables . . . . . . . . . . . . . . . . . . .  53
     Multi-branch  . . . . . . . . . . . . . . . . . . . . . . .  53
     Starting values . . . . . . . . . . . . . . . . . . . . . .  54
     Tips  . . . . . . . . . . . . . . . . . . . . . . . . . . .  54
     Help  . . . . . . . . . . . . . . . . . . . . . . . . . . .  56
     History . . . . . . . . . . . . . . . . . . . . . . . . . .  56
     If  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  57
     Load  . . . . . . . . . . . . . . . . . . . . . . . . . . .  57
     Lower . . . . . . . . . . . . . . . . . . . . . . . . . . .  58
     Pause . . . . . . . . . . . . . . . . . . . . . . . . . . .  58
     Plot  . . . . . . . . . . . . . . . . . . . . . . . . . . .  60
     Data  . . . . . . . . . . . . . . . . . . . . . . . . . . .  60
     Binary  . . . . . . . . . . . . . . . . . . . . . . . . . .  63
     Binary general  . . . . . . . . . . . . . . . . . . . . . .  63
     Array . . . . . . . . . . . . . . . . . . . . . . . . . . .  65










=1 .if 0 .tl 'GNUPLOT 4.1''%'


     Record  . . . . . . . . . . . . . . . . . . . . . . . . . .  65
     Format  . . . . . . . . . . . . . . . . . . . . . . . . . .  65
     Endian  . . . . . . . . . . . . . . . . . . . . . . . . . .  66
     Filetype  . . . . . . . . . . . . . . . . . . . . . . . . .  66
     Avs . . . . . . . . . . . . . . . . . . . . . . . . . . . .  67
     Edf . . . . . . . . . . . . . . . . . . . . . . . . . . . .  67
     Keywords  . . . . . . . . . . . . . . . . . . . . . . . . .  67
     Scan  . . . . . . . . . . . . . . . . . . . . . . . . . . .  67
     Transpose . . . . . . . . . . . . . . . . . . . . . . . . .  68
     Dx, dy, dz  . . . . . . . . . . . . . . . . . . . . . . . .  68
     Flipx, flipy, flipz . . . . . . . . . . . . . . . . . . . .  69
     Origin  . . . . . . . . . . . . . . . . . . . . . . . . . .  69
     Center  . . . . . . . . . . . . . . . . . . . . . . . . . .  69
     Rotate  . . . . . . . . . . . . . . . . . . . . . . . . . .  69
     Perpendicular . . . . . . . . . . . . . . . . . . . . . . .  70
     Binary examples . . . . . . . . . . . . . . . . . . . . . .  70
     Every . . . . . . . . . . . . . . . . . . . . . . . . . . .  71
     Example datafile  . . . . . . . . . . . . . . . . . . . . .  72
     Index . . . . . . . . . . . . . . . . . . . . . . . . . . .  73
     Smooth  . . . . . . . . . . . . . . . . . . . . . . . . . .  73
     Acsplines . . . . . . . . . . . . . . . . . . . . . . . . .  74
     Bezier  . . . . . . . . . . . . . . . . . . . . . . . . . .  75
     Csplines  . . . . . . . . . . . . . . . . . . . . . . . . .  75
     Sbezier . . . . . . . . . . . . . . . . . . . . . . . . . .  75
     Unique  . . . . . . . . . . . . . . . . . . . . . . . . . .  75
     Frequency . . . . . . . . . . . . . . . . . . . . . . . . .  75
     Special-filenames . . . . . . . . . . . . . . . . . . . . .  75
     Thru  . . . . . . . . . . . . . . . . . . . . . . . . . . .  77
     Using . . . . . . . . . . . . . . . . . . . . . . . . . . .  78
     Using title . . . . . . . . . . . . . . . . . . . . . . . .  80
     Xticlabels  . . . . . . . . . . . . . . . . . . . . . . . .  81
     X2ticlabels . . . . . . . . . . . . . . . . . . . . . . . .  81
     Yticlabels  . . . . . . . . . . . . . . . . . . . . . . . .  81
     Y2ticlabels . . . . . . . . . . . . . . . . . . . . . . . .  81
     Zticlabels  . . . . . . . . . . . . . . . . . . . . . . . .  82
     Errorbars . . . . . . . . . . . . . . . . . . . . . . . . .  82
     Errorlines  . . . . . . . . . . . . . . . . . . . . . . . .  83
     Parametric  . . . . . . . . . . . . . . . . . . . . . . . .  84
     Ranges  . . . . . . . . . . . . . . . . . . . . . . . . . .  84
     Title . . . . . . . . . . . . . . . . . . . . . . . . . . .  86
     With  . . . . . . . . . . . . . . . . . . . . . . . . . . .  87
     Print . . . . . . . . . . . . . . . . . . . . . . . . . . .  89
     Pwd . . . . . . . . . . . . . . . . . . . . . . . . . . . .  90
     Quit  . . . . . . . . . . . . . . . . . . . . . . . . . . .  90
     Raise . . . . . . . . . . . . . . . . . . . . . . . . . . .  90
     Replot  . . . . . . . . . . . . . . . . . . . . . . . . . .  91
     Reread  . . . . . . . . . . . . . . . . . . . . . . . . . .  91
     Reset . . . . . . . . . . . . . . . . . . . . . . . . . . .  92
     Save  . . . . . . . . . . . . . . . . . . . . . . . . . . .  93
     Set-show  . . . . . . . . . . . . . . . . . . . . . . . . .  94
     Angles  . . . . . . . . . . . . . . . . . . . . . . . . . .  94
     Arrow . . . . . . . . . . . . . . . . . . . . . . . . . . .  95
     Autoscale . . . . . . . . . . . . . . . . . . . . . . . . .  97










GNUPLOT 4.1                                                       iv


     Parametric mode . . . . . . . . . . . . . . . . . . . . . .  99
     Polar mode  . . . . . . . . . . . . . . . . . . . . . . . . 100
     Bars  . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
     Bmargin . . . . . . . . . . . . . . . . . . . . . . . . . . 100
     Border  . . . . . . . . . . . . . . . . . . . . . . . . . . 101
     Boxwidth  . . . . . . . . . . . . . . . . . . . . . . . . . 102
     Clabel  . . . . . . . . . . . . . . . . . . . . . . . . . . 103
     Clip  . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
     Cntrparam . . . . . . . . . . . . . . . . . . . . . . . . . 105
     Color box . . . . . . . . . . . . . . . . . . . . . . . . . 107
     Contour . . . . . . . . . . . . . . . . . . . . . . . . . . 108
     Data style  . . . . . . . . . . . . . . . . . . . . . . . . 109
     Datafile  . . . . . . . . . . . . . . . . . . . . . . . . . 109
     Set datafile fortran  . . . . . . . . . . . . . . . . . . . 109
     Set datafile missing  . . . . . . . . . . . . . . . . . . . 110
     Set datafile separator  . . . . . . . . . . . . . . . . . . 111
     Set datafile commentschars  . . . . . . . . . . . . . . . . 111
     Set datafile binary . . . . . . . . . . . . . . . . . . . . 112
     Decimalsign . . . . . . . . . . . . . . . . . . . . . . . . 112
     Dgrid3d . . . . . . . . . . . . . . . . . . . . . . . . . . 113
     Dummy . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
     Encoding  . . . . . . . . . . . . . . . . . . . . . . . . . 115
     Fit . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
     Fontpath  . . . . . . . . . . . . . . . . . . . . . . . . . 117
     Format  . . . . . . . . . . . . . . . . . . . . . . . . . . 118
     Gprintf . . . . . . . . . . . . . . . . . . . . . . . . . . 118
     Format specifiers . . . . . . . . . . . . . . . . . . . . . 119
     Time/date specifiers  . . . . . . . . . . . . . . . . . . . 120
     Function style  . . . . . . . . . . . . . . . . . . . . . . 122
     Functions . . . . . . . . . . . . . . . . . . . . . . . . . 122
     Grid  . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
     Hidden3d  . . . . . . . . . . . . . . . . . . . . . . . . . 123
     Historysize . . . . . . . . . . . . . . . . . . . . . . . . 126
     Isosamples  . . . . . . . . . . . . . . . . . . . . . . . . 126
     Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
     Label . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
     Lmargin . . . . . . . . . . . . . . . . . . . . . . . . . . 134
     Loadpath  . . . . . . . . . . . . . . . . . . . . . . . . . 134
     Locale  . . . . . . . . . . . . . . . . . . . . . . . . . . 135
     Logscale  . . . . . . . . . . . . . . . . . . . . . . . . . 135
     Macros  . . . . . . . . . . . . . . . . . . . . . . . . . . 136
     Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . 136
     Margin  . . . . . . . . . . . . . . . . . . . . . . . . . . 137
     Mouse . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
     X11 mouse . . . . . . . . . . . . . . . . . . . . . . . . . 139
     Multiplot . . . . . . . . . . . . . . . . . . . . . . . . . 140
     Mx2tics . . . . . . . . . . . . . . . . . . . . . . . . . . 142
     Mxtics  . . . . . . . . . . . . . . . . . . . . . . . . . . 142
     My2tics . . . . . . . . . . . . . . . . . . . . . . . . . . 143
     Mytics  . . . . . . . . . . . . . . . . . . . . . . . . . . 143
     Mztics  . . . . . . . . . . . . . . . . . . . . . . . . . . 143
     Offsets . . . . . . . . . . . . . . . . . . . . . . . . . . 143
     Origin  . . . . . . . . . . . . . . . . . . . . . . . . . . 144










GNUPLOT 4.1                                                        v


     Output  . . . . . . . . . . . . . . . . . . . . . . . . . . 144
     Parametric  . . . . . . . . . . . . . . . . . . . . . . . . 145
     Plot  . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
     Pm3d  . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
     Palette . . . . . . . . . . . . . . . . . . . . . . . . . . 151
     Rgbformulae . . . . . . . . . . . . . . . . . . . . . . . . 154
     Defined . . . . . . . . . . . . . . . . . . . . . . . . . . 154
     Functions . . . . . . . . . . . . . . . . . . . . . . . . . 156
     File  . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
     Gamma correction  . . . . . . . . . . . . . . . . . . . . . 157
     Postscript  . . . . . . . . . . . . . . . . . . . . . . . . 158
     Colornames  . . . . . . . . . . . . . . . . . . . . . . . . 159
     Pointsize . . . . . . . . . . . . . . . . . . . . . . . . . 159
     Polar . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
     Print . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
     Object  . . . . . . . . . . . . . . . . . . . . . . . . . . 161
     Rmargin . . . . . . . . . . . . . . . . . . . . . . . . . . 162
     Rrange  . . . . . . . . . . . . . . . . . . . . . . . . . . 162
     Samples . . . . . . . . . . . . . . . . . . . . . . . . . . 162
     Size  . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
     Style . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
     Set style arrow . . . . . . . . . . . . . . . . . . . . . . 165
     Set style data  . . . . . . . . . . . . . . . . . . . . . . 166
     Set style fill  . . . . . . . . . . . . . . . . . . . . . . 167
     Set style function  . . . . . . . . . . . . . . . . . . . . 167
     Set style increment . . . . . . . . . . . . . . . . . . . . 168
     Set style line  . . . . . . . . . . . . . . . . . . . . . . 168
     Plotting styles . . . . . . . . . . . . . . . . . . . . . . 170
     Set style rectangle . . . . . . . . . . . . . . . . . . . . 171
     Boxerrorbars  . . . . . . . . . . . . . . . . . . . . . . . 172
     Boxes . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
     Boxxyerrorbars  . . . . . . . . . . . . . . . . . . . . . . 174
     Candlesticks  . . . . . . . . . . . . . . . . . . . . . . . 174
     Dots  . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
     Filledcurves  . . . . . . . . . . . . . . . . . . . . . . . 176
     Financebars . . . . . . . . . . . . . . . . . . . . . . . . 177
     Fsteps  . . . . . . . . . . . . . . . . . . . . . . . . . . 177
     Histeps . . . . . . . . . . . . . . . . . . . . . . . . . . 178
     Histograms  . . . . . . . . . . . . . . . . . . . . . . . . 178
     Newhistogram  . . . . . . . . . . . . . . . . . . . . . . . 181
     Image . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
     Impulses  . . . . . . . . . . . . . . . . . . . . . . . . . 183
     Labels  . . . . . . . . . . . . . . . . . . . . . . . . . . 183
     Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
     Linespoints . . . . . . . . . . . . . . . . . . . . . . . . 184
     Points  . . . . . . . . . . . . . . . . . . . . . . . . . . 184
     Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
     Rgbimage  . . . . . . . . . . . . . . . . . . . . . . . . . 184
     Vectors . . . . . . . . . . . . . . . . . . . . . . . . . . 185
     Xerrorbars  . . . . . . . . . . . . . . . . . . . . . . . . 185
     Xyerrorbars . . . . . . . . . . . . . . . . . . . . . . . . 185
     Yerrorbars  . . . . . . . . . . . . . . . . . . . . . . . . 186
     Xerrorlines . . . . . . . . . . . . . . . . . . . . . . . . 186










GNUPLOT 4.1                                                       vi


     Xyerrorlines  . . . . . . . . . . . . . . . . . . . . . . . 186
     Yerrorlines . . . . . . . . . . . . . . . . . . . . . . . . 187
     Surface . . . . . . . . . . . . . . . . . . . . . . . . . . 187
     Table . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
     Terminal  . . . . . . . . . . . . . . . . . . . . . . . . . 188
     Termoption  . . . . . . . . . . . . . . . . . . . . . . . . 189
     Tics  . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
     Ticslevel . . . . . . . . . . . . . . . . . . . . . . . . . 190
     Ticscale  . . . . . . . . . . . . . . . . . . . . . . . . . 191
     Timestamp . . . . . . . . . . . . . . . . . . . . . . . . . 191
     Timefmt . . . . . . . . . . . . . . . . . . . . . . . . . . 191
     Title . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
     Tmargin . . . . . . . . . . . . . . . . . . . . . . . . . . 193
     Trange  . . . . . . . . . . . . . . . . . . . . . . . . . . 194
     Urange  . . . . . . . . . . . . . . . . . . . . . . . . . . 194
     Variables . . . . . . . . . . . . . . . . . . . . . . . . . 194
     Version . . . . . . . . . . . . . . . . . . . . . . . . . . 194
     View  . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
     Vrange  . . . . . . . . . . . . . . . . . . . . . . . . . . 195
     X2data  . . . . . . . . . . . . . . . . . . . . . . . . . . 196
     X2dtics . . . . . . . . . . . . . . . . . . . . . . . . . . 196
     X2label . . . . . . . . . . . . . . . . . . . . . . . . . . 196
     X2mtics . . . . . . . . . . . . . . . . . . . . . . . . . . 196
     X2range . . . . . . . . . . . . . . . . . . . . . . . . . . 196
     X2tics  . . . . . . . . . . . . . . . . . . . . . . . . . . 196
     X2zeroaxis  . . . . . . . . . . . . . . . . . . . . . . . . 197
     Xdata . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
     Xdtics  . . . . . . . . . . . . . . . . . . . . . . . . . . 197
     Xlabel  . . . . . . . . . . . . . . . . . . . . . . . . . . 198
     Xmtics  . . . . . . . . . . . . . . . . . . . . . . . . . . 200
     Xrange  . . . . . . . . . . . . . . . . . . . . . . . . . . 200
     Xtics . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
     Xyplane . . . . . . . . . . . . . . . . . . . . . . . . . . 205
     Xzeroaxis . . . . . . . . . . . . . . . . . . . . . . . . . 206
     Y2data  . . . . . . . . . . . . . . . . . . . . . . . . . . 206
     Y2dtics . . . . . . . . . . . . . . . . . . . . . . . . . . 206
     Y2label . . . . . . . . . . . . . . . . . . . . . . . . . . 206
     Y2mtics . . . . . . . . . . . . . . . . . . . . . . . . . . 206
     Y2range . . . . . . . . . . . . . . . . . . . . . . . . . . 207
     Y2tics  . . . . . . . . . . . . . . . . . . . . . . . . . . 207
     Y2zeroaxis  . . . . . . . . . . . . . . . . . . . . . . . . 207
     Ydata . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
     Ydtics  . . . . . . . . . . . . . . . . . . . . . . . . . . 207
     Ylabel  . . . . . . . . . . . . . . . . . . . . . . . . . . 207
     Ymtics  . . . . . . . . . . . . . . . . . . . . . . . . . . 208
     Yrange  . . . . . . . . . . . . . . . . . . . . . . . . . . 208
     Ytics . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
     Yzeroaxis . . . . . . . . . . . . . . . . . . . . . . . . . 208
     Zdata . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
     Zdtics  . . . . . . . . . . . . . . . . . . . . . . . . . . 208
     Zzeroaxis . . . . . . . . . . . . . . . . . . . . . . . . . 208
     Cbdata  . . . . . . . . . . . . . . . . . . . . . . . . . . 209
     Cbdtics . . . . . . . . . . . . . . . . . . . . . . . . . . 209










GNUPLOT 4.1                                                      vii


     Zero  . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
     Zeroaxis  . . . . . . . . . . . . . . . . . . . . . . . . . 209
     Zlabel  . . . . . . . . . . . . . . . . . . . . . . . . . . 210
     Zmtics  . . . . . . . . . . . . . . . . . . . . . . . . . . 210
     Zrange  . . . . . . . . . . . . . . . . . . . . . . . . . . 210
     Ztics . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
     Cblabel . . . . . . . . . . . . . . . . . . . . . . . . . . 211
     Cbmtics . . . . . . . . . . . . . . . . . . . . . . . . . . 211
     Cbrange . . . . . . . . . . . . . . . . . . . . . . . . . . 211
     Cbtics  . . . . . . . . . . . . . . . . . . . . . . . . . . 211
     Shell . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
     Splot . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
     Data-file . . . . . . . . . . . . . . . . . . . . . . . . . 213
     Binary matrix . . . . . . . . . . . . . . . . . . . . . . . 214
     Example datafile  . . . . . . . . . . . . . . . . . . . . . 215
     Matrix_ascii  . . . . . . . . . . . . . . . . . . . . . . . 216
     Matrix  . . . . . . . . . . . . . . . . . . . . . . . . . . 217
     Grid data . . . . . . . . . . . . . . . . . . . . . . . . . 217
     Splot overview  . . . . . . . . . . . . . . . . . . . . . . 218
     System  . . . . . . . . . . . . . . . . . . . . . . . . . . 219
     Test  . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
     Unset . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
     Update  . . . . . . . . . . . . . . . . . . . . . . . . . . 219
     Terminal types  . . . . . . . . . . . . . . . . . . . . . . 220
     Terminal  . . . . . . . . . . . . . . . . . . . . . . . . . 220
     Aed767  . . . . . . . . . . . . . . . . . . . . . . . . . . 220
     Aifm  . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
     Amiga . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
     Apollo  . . . . . . . . . . . . . . . . . . . . . . . . . . 222
     Aqua  . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
     Atari ST (via AES)  . . . . . . . . . . . . . . . . . . . . 222
     Be  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
     Command-line_options  . . . . . . . . . . . . . . . . . . . 224
     Monochrome_options  . . . . . . . . . . . . . . . . . . . . 225
     Color_resources . . . . . . . . . . . . . . . . . . . . . . 225
     Grayscale_resources . . . . . . . . . . . . . . . . . . . . 226
     Line_resources  . . . . . . . . . . . . . . . . . . . . . . 226
     Cgi . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
     Cgm . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
     Font  . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
     Fontsize  . . . . . . . . . . . . . . . . . . . . . . . . . 231
     Linewidth . . . . . . . . . . . . . . . . . . . . . . . . . 231
     Rotate  . . . . . . . . . . . . . . . . . . . . . . . . . . 231
     Solid . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
     Size  . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
     Width . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
     Nofontlist  . . . . . . . . . . . . . . . . . . . . . . . . 232
     Corel . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
     Debug . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
     Dospc . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
     Dumb  . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
     Dxf . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
     Dxy800a . . . . . . . . . . . . . . . . . . . . . . . . . . 234










GNUPLOT 4.1                                                     viii


     Eepic . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
     Emf . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
     Emxvga  . . . . . . . . . . . . . . . . . . . . . . . . . . 237
     Epslatex  . . . . . . . . . . . . . . . . . . . . . . . . . 237
     Epson-180dpi  . . . . . . . . . . . . . . . . . . . . . . . 242
     Excl  . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
     Fig . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
     Ggi . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
     Gif . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
     Gnugraph(GNU plotutils) . . . . . . . . . . . . . . . . . . 247
     Gpic  . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
     Gpr . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
     Grass . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
     Hercules  . . . . . . . . . . . . . . . . . . . . . . . . . 249
     Hp2623a . . . . . . . . . . . . . . . . . . . . . . . . . . 250
     Hp2648  . . . . . . . . . . . . . . . . . . . . . . . . . . 250
     Hp500c  . . . . . . . . . . . . . . . . . . . . . . . . . . 250
     Hpgl  . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
     Hpljii  . . . . . . . . . . . . . . . . . . . . . . . . . . 252
     Hppj  . . . . . . . . . . . . . . . . . . . . . . . . . . . 252
     Imagen  . . . . . . . . . . . . . . . . . . . . . . . . . . 252
     Iris4d  . . . . . . . . . . . . . . . . . . . . . . . . . . 253
     Jpeg  . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
     Kyo . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
     Latex . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
     Linux . . . . . . . . . . . . . . . . . . . . . . . . . . . 256
     Macintosh . . . . . . . . . . . . . . . . . . . . . . . . . 256
     Mf  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257
     METAFONT Instructions . . . . . . . . . . . . . . . . . . . 258
     Mgr . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259
     Mif . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259
     Mp  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
     Metapost Instructions . . . . . . . . . . . . . . . . . . . 263
     Mtos  . . . . . . . . . . . . . . . . . . . . . . . . . . . 264
     Next  . . . . . . . . . . . . . . . . . . . . . . . . . . . 264
     Openstep (next) . . . . . . . . . . . . . . . . . . . . . . 264
     Pbm . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
     Pdf . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266
     Pm  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
     Png . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
     Postscript  . . . . . . . . . . . . . . . . . . . . . . . . 269
     Enhanced postscript . . . . . . . . . . . . . . . . . . . . 272
     Editing postscript  . . . . . . . . . . . . . . . . . . . . 274
     Postscript fontfile . . . . . . . . . . . . . . . . . . . . 275
     Postscript prologue . . . . . . . . . . . . . . . . . . . . 277
     Pslatex and pstex . . . . . . . . . . . . . . . . . . . . . 277
     Pstricks  . . . . . . . . . . . . . . . . . . . . . . . . . 280
     Qms . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280
     Regis . . . . . . . . . . . . . . . . . . . . . . . . . . . 280
     Rgip  . . . . . . . . . . . . . . . . . . . . . . . . . . . 281
     Sun . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281
     Svg . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281
     Svga  . . . . . . . . . . . . . . . . . . . . . . . . . . . 282










GNUPLOT 4.1                                                       ix


     Tek40 . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
     Tek410x . . . . . . . . . . . . . . . . . . . . . . . . . . 283
     Texdraw . . . . . . . . . . . . . . . . . . . . . . . . . . 283
     Tgif  . . . . . . . . . . . . . . . . . . . . . . . . . . . 283
     Tkcanvas  . . . . . . . . . . . . . . . . . . . . . . . . . 285
     Tpic  . . . . . . . . . . . . . . . . . . . . . . . . . . . 286
     Unixpc  . . . . . . . . . . . . . . . . . . . . . . . . . . 286
     Unixplot  . . . . . . . . . . . . . . . . . . . . . . . . . 286
     Atari ST (via VDI)  . . . . . . . . . . . . . . . . . . . . 287
     Vgagl . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
     VWS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288
     Vx384 . . . . . . . . . . . . . . . . . . . . . . . . . . . 288
     Windows . . . . . . . . . . . . . . . . . . . . . . . . . . 289
     Graph-menu  . . . . . . . . . . . . . . . . . . . . . . . . 289
     Printing  . . . . . . . . . . . . . . . . . . . . . . . . . 290
     Text-menu . . . . . . . . . . . . . . . . . . . . . . . . . 290
     Wgnuplot.ini  . . . . . . . . . . . . . . . . . . . . . . . 292
     Windows3.0  . . . . . . . . . . . . . . . . . . . . . . . . 293
     Wxt . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
     X11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
     X11_fonts . . . . . . . . . . . . . . . . . . . . . . . . . 297
     Command-line_options  . . . . . . . . . . . . . . . . . . . 298
     Monochrome_options  . . . . . . . . . . . . . . . . . . . . 299
     Color_resources . . . . . . . . . . . . . . . . . . . . . . 300
     Grayscale_resources . . . . . . . . . . . . . . . . . . . . 301
     Line_resources  . . . . . . . . . . . . . . . . . . . . . . 301
     X11 pm3d_resources  . . . . . . . . . . . . . . . . . . . . 302
     X11 other_resources . . . . . . . . . . . . . . . . . . . . 304
     Xlib  . . . . . . . . . . . . . . . . . . . . . . . . . . . 304
     Graphical User Interfaces . . . . . . . . . . . . . . . . . 305
     Bugs  . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
     Gnuplot limitations . . . . . . . . . . . . . . . . . . . . 305
     Specific terminals  . . . . . . . . . . . . . . . . . . . . 306
     External libraries  . . . . . . . . . . . . . . . . . . . . 306

























