Gnuplot FAQ                                  
                                                                               
This document deals with gnuplot version 4.0 which is the latest official
release as of April 2004.
Its version is $Revision: 1.15 $, dated $Date: 2004/04/14 13:18:59 $.


目次

 ・ 0 Meta - Questions
     □ 0.1 Where do I get this document?
     □ 0.2 Where do I send comments about this document?
   
 ・ 1 General Information
     □ 1.1 What is gnuplot?
     □ 1.2 How did it come about and why is it called gnuplot?
     □ 1.3 What does gnuplot offer?
     □ 1.4 Is gnuplot suitable for scripting?
     □ 1.5 Can I run gnuplot on my computer?
     □ 1.6 Legalities
     □ 1.7 Does gnuplot have anything to do with the FSF and the GNU project?
     □ 1.8 Where do I get further information?
   
 ・ 2 Setting it up
     □ 2.1 What is the current version of gnuplot?
     □ 2.2 Where can I get gnuplot?
     □ 2.3 Where can I get current development version of gnuplot?
     □ 2.4 How do I get gnuplot to compile on my system?
     □ 2.5 What documentation is there, and how do I get it?
     □ 2.6 Worked examples
     □ 2.7 How do I modify gnuplot, and apply 'patches'?
   
 ・ 3 Working with it.
     □ 3.1 How do I get help?
     □ 3.2 How do I print out my graphs?
     □ 3.3 How do I include my graphs in <word processor>?
     □ 3.4 How do I edit or post-process a gnuplot graph?
     □ 3.5 How do I change symbol size, line thickness and the like?
     □ 3.6 How do I generate plots in GIF format?
     □ 3.7 Can I animate my graphs?
     □ 3.8 How do I plot implicit defined graphs?
     □ 3.9 How to fill an area between two curves
     □ 3.10 Pm3d splot from a datafile does not draw anything
     □ 3.11 Drawing a (color) map, i.e. 2D projection of 3D data
     □ 3.12 How to overlay dots/points scatter plot onto a pm3d map/surface
     □ 3.13 How to draw black contour plot, and contours with labels
     □ 3.14 How to overlay contour plot over pm3d map/surface
     □ 3.15 Color facets with pm3d
     □ 3.16 Palette for printing my color map on color as well as blank&white
        printer?
   
 ・ 4 Wanted features
     □ 4.1 What's new in gnuplot 3.7, 4.0 etc?
     □ 4.2 Does gnuplot support a driver for <graphics format>?
     □ 4.3 Does gnuplot have hidden line removal?
     □ 4.4 Does gnuplot support bar-charts/histograms/boxes?
     □ 4.5 Does gnuplot support pie charts?
     □ 4.6 Does gnuplot quarterly time charts?
     □ 4.7 Can I put multiple pages on one page?
     □ 4.8 Does gnuplot support multiple y-axes on a single plot?
     □ 4.9 Can I put both commands and data into a single file?
     □ 4.10 Can I put Greek letters and super/subscripts into my labels?
     □ 4.11 How do I include accented characters
     □ 4.12 Can I do 1:1 scaling of axes?
     □ 4.13 Can I put different text sizes into my plots?
     □ 4.14 How do I skip data points?
     □ 4.15 How do I plot every nth point?
     □ 4.16 How do I plot a vertical line?
     □ 4.17 How do I plot data files
     □ 4.18 How do I replot multiplot drawing
   
 ・ 5 Miscellaneous
     □ 5.1 I've found a bug, what do I do?
     □ 5.2 Can I use gnuplot routines for my own programs?
     □ 5.3 What extensions have people made to gnuplot? Where can I get them?
     □ 5.4 I need an integration, fft, iir-filter,...!
     □ 5.5 Can I do heavy-duty data processing with gnuplot? or What is beyond
        gnuplot?
     □ 5.6 Mouse in my interactive terminal does not work
     □ 5.7 How to use hotkeys in my interactive terminals
     □ 5.8 I have ported gnuplot to another system, or patched it. What do I
        do?
     □ 5.9 I want to help in developing the next version of gnuplot. What can
        I do?
     □ 5.10 Open questions for inclusion into the FAQ?
   
 ・ 6 Making life easier
     □ 6.1 How do I plot two functions in non-overlapping regions?
     □ 6.2 How do I run my data through a filter before plotting?
     □ 6.3 How do I make it easier to use gnuplot with L^ATEX?
     □ 6.4 How do I save and restore my settings?
     □ 6.5 How do I plot lines (not grids) using splot?
     □ 6.6 How do I plot a function f(x,y) that is bounded by other functions
        in the x-y plane?
     □ 6.7 How do I turn off <feature> in a plot?
     □ 6.8 How do I call gnuplot from my own programs?
     □ 6.9 What if I need h-bar (Planck's constant)?
     □ 6.10 How do a produce blank output page?
   
 ・ 7 Common problems
     □ 7.1 Gnuplot is not plotting any points under X11! How come?
     □ 7.2 My isoline data generated by a Fortran program is not handled
        correctly. What can I do?
     □ 7.3 Why does gnuplot ignore my very small numbers?
     □ 7.4 Gnuplot is not plotting on the screen when run from command line
        via 'gnuplot filename.gp'
     □ 7.5 My formulas (like 1/3) are giving me nonsense results! What's going
        on?
     □ 7.6 Set output 'filename' isn't outputting everything it should!
     □ 7.7 When using the L^ATEX-terminal, there is an error during the L^
        ATEX-run!
     □ 7.8 The exit command does not work as documented!
     □ 7.9 I can't find the demos and example files at the URLs in the
        documentation!
     □ 7.10 Calling gnuplot in a pipe or with a gnuplot-script doesn't produce
        a plot!
   
 ・ 8 Credits

0 Meta - Questions

0.1 Where do I get this document?

The newest version of this document is on the web at http://www.gnuplot.info/
faq/.

This document was/is posted sometimes to the newsgroups  ~
comp.graphics.apps.gnuplot.

0.2 Where do I send comments about this document?

Send comments, suggestions etc via email to the developer mailing list 
gnuplot-beta@lists.sourceforge.net. Please contribute your suggestions with
respect to the file faq.tex available from http://cvs.sourceforge.net/
viewcvs.py/gnuplot/faq/.

1 General Information

1.1 What is gnuplot?

gnuplot is a command-driven interactive function plotting program. It can be
used to plot functions and data points in both two- and three-dimensional plots
in many different formats. It is designed primarily for the visual display of
scientific data. gnuplot is copyrighted, but freely distributable; you don't
have to pay for it.

1.2 How did it come about and why is it called gnuplot?

The authors of gnuplot are: Thomas Williams, Colin Kelley, Russell Lang, Dave
Kotz, John Campbell, Gershon Elber, Alexander Woo and many others.

The following quote comes from Thomas Williams:

    I was taking a differential equation class and Colin was taking
    Electromagnetics, we both thought it'd be helpful to visualize the
    mathematics behind them. We were both working as sys admin for an EE VLSI
    lab, so we had the graphics terminals and the time to do some coding. The
    posting was better received than we expected, and prompted us to add some,
    albeit lame, support for file data.

    Any reference to GNUplot is incorrect. The real name of the program is
    "gnuplot". You see people use "Gnuplot" quite a bit because many of us have
    an aversion to starting a sentence with a lower case letter, even in the
    case of proper nouns and titles. gnuplot is not related to the GNU project
    or the FSF in any but the most peripheral sense. Our software was designed
    completely independently and the name "gnuplot" was actually a compromise.
    I wanted to call it "llamaplot" and Colin wanted to call it "nplot." We
    agreed that "newplot" was acceptable but, we then discovered that there was
    an absolutely ghastly pascal program of that name that the Computer Science
    Dept. occasionally used. I decided that "gnuplot" would make a nice pun and
    after a fashion Colin agreed.

1.3 What does gnuplot offer?

 ・ Plotting two-dimensional functions and data points in many different styles
    (points, lines, error bars)
 ・ Plotting three-dimensional data points and surfaces in many different
    styles (contour plot, mesh)
 ・ Algebraic computation in integer, float and complex arithmetic
 ・ User-defined functions and hot-keys
 ・ Support for a large number of operating systems, graphics file formats and
    output devices
 ・ Extensive on-line help
 ・ TEX-like text formatting for labels, titles, axes, data points
 ・ Interactive command line editing and history (most platforms)

1.4 Is gnuplot suitable for scripting?

Yes. Gnuplot can read in files containing additional commands during an
interactive session, or it can be run in batch mode by piping a pre-existing
file or a stream of commands to stdin. Gnuplot is used as a back-end graphics
driver by such higher-level mathematical packages as Octave, and can easily be
wrapped in a cgi script for use as a web-driven plot generator.

1.5 Can I run gnuplot on my computer?

Gnuplot is available for a number of platforms. These are: Unix (X11 and
NeXTSTEP), Linux, VMS, OS/2, MS-DOS, Amiga, MS-Windows, OS-9/68k, Atari ST,
BeOS, and Macintosh.

Please notify the FAQ-maintainer of any further ports you might be aware of.

You should be able to compile the gnuplot source more or less out of the box on
any reasonable standard (ANSI/ISO C, POSIX) environment.

1.6 Legalities

Gnuplot is freeware authored by a collection of volunteers, who cannot make any
legal statement about the compliance or non-compliance of gnuplot or its uses.
There is also no warranty whatsoever. Use at your own risk.

Citing from the README of a mathematical subroutine package by R. Freund:

    For all intent and purpose, any description of what the codes are doing
    should be construed as being a note of what we thought the codes did on our
    machine on a particular Tuesday of last year. If you're really lucky, they
    might do the same for you someday. Then again, do you really feel *that*
    lucky?

1.7 Does gnuplot have anything to do with the FSF and the GNU project?

Gnuplot is neither written nor maintained by the FSF. It is not covered by the
General Public License, either. It used to be distributed by the FSF, however,
due to licensing issues it is no longer.

Gnuplot is freeware in the sense that you don't have to pay for it. However it
is not freeware in the sense that you would be allowed to distribute a modified
version of your gnuplot freely. Please read and accept the Copyright file in
your distribution.

1.8 Where do I get further information?

See the main gnuplot web page http://www.gnuplot.info and references therein,
mainly gnuplot links http://gnuplot.sourceforge.net/links.html.

Some documentation and tutorials are available in other languages than English.
See http://gnuplot.sourceforge.net/help.html, section "Localized learning pages
about gnuplot", for the most up-to-date list.

2 Setting it up

2.1 What is the current version of gnuplot?

The current released version of gnuplot is 4.0.


2.2 Where can I get gnuplot?

The best place is definitely http://www.gnuplot.info. From there you find
various pointers to other sites.

The source distribution ("gnuplot-4.0.0.tar.gz" or a similar name) is available
from the official distribution site and its mirrors.

The main server is ftp.gnuplot.info in /pub/gnuplot/. This server is mirrored
by several others, among those are

 ・ mirror.aarnet.edu.au in /pub/gnuplot/
 ・ ftp.dartmouth.edu in /pub/gnuplot/
 ・ ftp.irisa.fr in /pub/gnuplot/
 ・ ftp.gnuplot.vt.edu in /pub/gnuplot/

As of June 1999, the gnuplot distribution is also mirrored at the Comprehensive
TeX Archive Network (CTAN) in the graphics/gnuplot directory. See

 ・ http://www.ctan.org/.

The following platform-specific sites below still exist, but may or may not
still hold gnuplot executables.

 ・ Source and binary distributions for the Amiga are available on Aminet 
    ftp.wustl.edu in  aminet/ and its mirrors, for example ftp.uni-kl.de,
    oes.orst.edu or ftp.luth.se.
   
 ・ MS-DOS and MS-Windows binaries are available from the above servers and are
    called for example gp37dos.zip, gp37dj.zip, gp37w16.zip, gp37mgw.zip,
    gnuplot3.7cyg.zip. OS/2 binaries are called gp37os2.zip.
   
 ・ The NeXTSTEP front end can be found at next-ftp.peak.org in /pub/next/
    binaries/plotting/Gnuplot1.2_bin.tar.Z.
   
 ・ A version for OS-9/68K can be found at cabrales.cs.wisc.edu in /pub/OSK/
    GRAPHICS/gnuplot32x.tar.Z; it includes both an X-Window Systems and a non -
    X-Window Systems version.
   
 ・ Versions for the Atari ST and TT, which include some GEM windowing support,
    are available from ftp.uni-kl.de in /pub/atari/graphics/, as gplt35st.zip
    and gplt35tt.zip. They work best under MiNT.
   
 ・ Executable files, plus documentation in Japanese, exist for the X680x0 on 
    ftp.csis.oita-u.ac.jp in /pub/x68k/fj.binaries.x68000/vol2.
   
2.3 Where can I get current development version of gnuplot?

The development version of gnuplot is availble as a cvs source tree online for
direct browsing from http://www.sourceforge.net/projects/gnuplot/, section
"CVS". You can download all current sources according to the documentation
therein; for example by a sequence of commands like

  export CVSROOT=:pserver:anonymous@cvs.gnuplot.sourceforge.net:/cvsroot/gnuplot
  cvs login
  cvs -z3 checkout gnuplot

Further, before the ./configure command of gnuplot compilation phase, you have
to execute ./prepare to create the up-to-date configure files.

There are no official preliminary binary releases of gnuplot: you have to
compile it yourself. However, you may find unofficial binary releases for some
platforms, like OS/2, Windows or Macintosh.

Important note: questions related to the development version should go to 
gnuplot-beta@lists.sourceforge.net.

2.4 How do I get gnuplot to compile on my system?

As you would any other installation. Read the files README.1ST and README.

 ・ For Unix, use ./configure (or ./configure -prefix=$HOME/usr for an
    installation for a single user), make and finally make install or make
    install-strip, the latter for smaller executables without debugging
    information. If you want to make a RPM package, then replace the latest
    step by checkinstall or checkinstall make install-strip, supposing the
    package checkinstall on your machine.
 ・ For DOS, if you are using bash and DJGPP, you can just run djconfig.sh.
 ・ For other platforms, copy the relevant makefile (e.g. makefile.os2 for OS/
    2, or makefile.mgw or makefile.cyg for Windows) from config/ to src/,
    optionally update options in the makefile's header, then change directory
    to src and run make.

2.5 What documentation is there, and how do I get it?

The documentation is included in the source distribution. Look at the docs
subdirectory, where you'll find

 ・ a Unix man page, which says how to start gnuplot
 ・ a help file, which also can be printed as a manual
 ・ a tutorial on using gnuplot with L^ATEX
 ・ a quick reference summary sheet for TEX only

The documentation is built during installation if you have L^ATEX installed on
your system, look in the directories docs and tutorial. make pdf in the docs
subdirectory will make a gnuplot.pdf hypertext file ready for browsing or
printing.

Online gnuplot documentation is available at http://gnuplot.sourceforge.net/
documentation.html.

(Obsolete?) PostScript copies of the documentation can be ftp'd from 
ftp.gnuplot.info in /pub/gnuplot, as manual.ps.Z and tutorial.ps.Z.
Documentation about gnuplot is available at the gnuplot distribution sites in
the files gpdoc.zip and gpdoc2.zip.

2.6 Worked examples

There is a directory of worked examples in the the source distribution. These
examples, and the resulting plots, may also be found at http://
gnuplot.sourceforge.net/demo/.

2.7 How do I modify gnuplot, and apply 'patches'?

For this, you will need to recompile gnuplot.

Modifications people make are either done by replacing files, such as terminal
drivers, or by 'patching'. If a file is a replacement, it will probably tell
you in its README or in the lines at the beginning.

To patch a file, you need the patch utility, and possibly also automake and
autoconf. On many UNIX systems these will already be installed; If they aren't,
you can find them wherever GNU software is archived. Typical command for
applying a patch is patch -p0 <newfunctionality.diff.

There is repository of contributed patches in the "Patches" section on
gnuplot's sourceforge site http://www.sourceforge.net/projects/gnuplot/.

3 Working with it.

3.1 How do I get help?

Read this document.

Give the help command at the initial prompt. After that, keep looking through
the keywords. Good starting points are plot and set.

Read the manual, if you have it.

Look through the demo subdirectory; it should give you some ideas.

Ask your colleagues, the system administrator or the person who set up gnuplot.

If all these fail, please upgrade to the newest version of gnuplot or urge your
system-administrator to do so. Then post a question to ~
comp.graphics.apps.gnuplot or send mail to the gatewayed mailing list 
gnuplot-info@lists.sourceforge.net. Do not forget to cite the version number
and the operating system. If you want to subscribe to the mailing list, send a
mail to majordomo@lists.sourceforge.net with the body of the message being
subscribe info-gnuplot. Please don't do this if you can get  ~
comp.graphics.apps.gnuplot directly. If you post a question there, it is
considered good form to solicit e-mail replies and post a summary.

3.2 How do I print out my graphs?

The kind of output produced is determined by the set terminal command; for
example, set terminal postscript will produce the graph in PostScript format.
Output can be redirected using the set output command.

As an example, the following prints out a graph of sin(x) on a Unix machine
running the X-Window System.

gnuplot> plot [-6:6] sin(x)
gnuplot> set terminal postscript
Terminal type set to 'postscript'
Options are 'landscape monochrome "Courier" 14'
gnuplot> set output "sin.ps"
gnuplot> replot
gnuplot> set output              # set output back to default
gnuplot> set terminal x11        # ditto for terminal type
gnuplot> ! lp -ops sin.ps        # print PS File (site dependent)
request id is lprint-3433 (standard input)
lp: printed file sin.ps on fg20.rz.uni-karlsruhe.de (5068 Byte)
!
gnuplot>

Using the platform-independent way of restoring terminal by set term push/pop
commands, do it by

gnuplot> set terminal postscript eps color lw 15 "Helvetica" 20
gnuplot> set out 'a.eps'
gnuplot> replot
gnuplot> set term pop

The command set term pop without a previous corresponding set term push
switches the terminal back to the startup terminal, e.g. x11, pm or win.

In Microschrott Windows you click in the upper left corner of the graph window
and print directly from there.

3.3 How do I include my graphs in <word processor>?

Basically, you save your plot to a file in a format your word processor can
understand (using set term and set output, see above), and then you read in the
plot from your word processor. Vector formats (PostScript, emf, svg, pdf, TEX,
L^ATEX, etc) should be preferred, as you can scale your graph later to the
right size.

Details depend on which word processor you use; use set term to get a list of
available file formats.

Many word processors can use Encapsulated PostScript for graphs. This can be
generated by the set terminal postscript eps [color] command. Note that it is a
good idea to check and correct the bounding box of the graphs in the eps files
(manually or by the fixbb script from gnuplot webpage), as you have to correct
this box for any eps figure produced by whichever program. Some (most?) word
processors do not preview the actual image in the eps file, and you have to add
the preview image yourself. You can use the GSView viewer for this (available
for OS/2, Windows and X11), or some Unix ps tool. Note that the preview image
increases size of the eps file; the smallest increase you may get by choosing
Tiff 6 Packbits.

Into some office applications, like OpenOffice.org, or into applications in the
Windows world, you can insert vectorial images produces by the emf terminal
type.

With TEX, it depends on what you use to print your dvi files. If you use dvips
or dvi2ps, you can use Encapsulated PostScript. For emTeX (popular for OS/2 and
MS-DOS), you can use emTeX, otherwise use the L^ATEX terminal type, which
generates a picture environment. You can also use epslatex to separate the
graphics and text parts. Other possibilities include pslatex or pstex
terminals, and metafont or metapost terminals.

With TEX processed by pdftex or pdflatex, you can use png, jpeg and pdf
terminal types. You can also use the postscript eps terminal and convert the
eps file externally to pdf by epstopdf. Another choice is the epslatex
terminal, after converting the eps part to pdf as above (the TEX part can
remain unchanged).

Most word processors can import bitmap images (png, pbm, etc). The disadvantage
of this approach is that the resolution of your plot is limited by the size of
the plot at the time it is generated by gnuplot, which is generally a much
lower resolution than the document will eventually be printed in.

Under IBM OS/2, MacOS and Micro$oft Windows you can use the clipboard to copy
your graph and paste it into your favourite word processor.

The mif terminal type produces output for FrameMaker.

3.4 How do I edit or post-process a gnuplot graph?

This depends on the terminal type you use.

 ・ X11 toolkits: You can use the terminal type fig and use the xfig drawing
    program to edit the plot afterwards. You can obtain the xfig program from
    its web site http://www.xfig.org. More information about the text-format
    used for fig can be found in the fig-package.
   
    You may use the tgif terminal, which creates output suitable for reading
    within tgif (http://bourbon.cs.umd.edu:8001/tgif/), an interactive 2-D
    drawing tool under X11.
   
 ・ You may use the svg terminal (scalable vector graphics), which can be
    further edited by a svg editor, e.g. Sodipodi (http://
    sodipodi.sourceforge.net), Sketch (http://sketch.sourceforge.net) or Dia (
    http://http://www.lysator.liu.se/ alla/dia).
   
 ・ PostScript or PDF output can be edited directly by tools such as Adobe
    Illustrator or Acrobat, or can be converted to a variety of other editable
    vector formats by the pstoedit package. Pstoedit is available at http://
    www.pstoedit.net.
   
 ・ The mif terminal type produces an editable FrameMaker document.
   
 ・ Bitmapped graphics (e.g. png, jpeg, pbm) can be edited using tools such as
    ImageMagick or Gimp. In general, you should use a vector graphics program
    to post-process vector graphic formats, and a pixel-based editing program
    to post-process pixel graphics.
   
3.5 How do I change symbol size, line thickness and the like?

Gnuplot offers a variety of commands to set line and point properties,
including color, thickness, point shape, etc. The command test will display a
test page for the currently selected terminal type showing the available
pre-defined combinations of color, size, shape, etc. The set style command can
be used to define additional combinations.

3.6 How do I generate plots in GIF format?

GIF support was provided by an external library, libgd. Version 1.6 of the gd
library dropped support for gif in favour of the superior png format. More
recent versions of libgd also support jpeg output. If your installation of
gnuplot is linked to the gd library, you will get support for whatever formats
(gif, png, jpeg) are in that version of libgd.

Thus, nowadays, the usual way is to output the image as png and then use your
favourite program to convert it into gif, either using command line (e.g.
convert f.png f.gif or nconvert -out gif f.png) or by any GUI program. Another
possibility is to output the image as (encapsulated) postscript and convert
(export) it into gif or png by ghostscript, e.g. convert -density 150 f.eps
f.gif or by any ghostscript-based GUI like gsview, gv or kghostview.

3.7 Can I animate my graphs?

First have a look at animate.dem in the demo directory of gnuplot. Basically,
animated graphs are a sequence of plots in a suitable format.

Then have a look at the tool whirlgif 3.04, available at http://www.danbbs.dk/
 dino/whirlgif. It reads run-length encoded gifs and packs them into a minimal
animation. On the web-pages you will find a manual and an example.

You can also write a small script to get gnuplot to output a family of GIF
files, then have it execute some animator such as gifsicle: http://www.lcdf.org
/ eddietwo/gifsicle or gifmerge http://the-labs.com/GIFMerge.

mpeg_encode will encode a sequence of images into an mpeg format movie.

3.8 How do I plot implicit defined graphs?

Implicit graphs or curves cannot be plotted directly in gnuplot. However there
is a workaround.

gnuplot> # as example. Place your definition in the following line
gnuplot> f(x,y) = y - x**2 / tan(y)
gnuplot> set contour base
gnuplot> set cntrparam levels discrete 0.0
gnuplot> set nosurface
gnuplot> set term table
gnuplot> set out 'curve.dat'
gnuplot> splot f(x,y)
gnuplot> set out
gnuplot> set term pop
gnuplot> plot 'curve.dat' w l

The trick is to draw the single contour line z=0 of the surface z=f(x,y), and
store the resulting contour curve to a gnuplot datafile.

3.9 How to fill an area between two curves

A plot with filled area between two given curves requires a parametric plot
with filledcurves closed. The example below demonstrates this for two curves f
(x) and g(x) with a tricky "folded" parameter t:

set parametric
f(x)=cos(x)
g(x)=sin(x)
xmax=pi/4
set xrange [0:xmax]
set trange [0:2*xmax]
path(t) = ( t<= xmax ? f(t) : g(2*xmax-t) )
fold(t) = (t <=xmax ? t : 2*xmax - t)
plot fold(t),path(t) with filledcurves closed

Note that the above code fills area between the two curves, not area satisfying
inequality g(x)<f(x). If you want the latter, you should use the ternary
operator in path(t) to return an undefined value (0/0) if the inequality is not
satisfied.

See the documentation for help parametric, help filledcurves, and help ternary.


3.10 Pm3d splot from a datafile does not draw anything

You do set pm3d; splot 'a.dat' and no plot but colorbox appears. Obviously,
there is no blank line in between two subsequent scans (isolines) in the data
file. Add blank lines! If you are curious what this means, then don't hesitate
to look to files like demo/glass.dat or demo/triangle.dat in the gnuplot demo
directory.

You can find useful the following awk script (call it e.g. addblanks.awk) which
adds blank lines to a data file whenever number in the first column changes:

/[:blank:]*#/ {next} # ignore comments (lines starting with #)
NF < 3 {next} # ignore lines which don't have at least 3 columns
$1 != prev {printf "\n"; prev=$1} # print blank line
{print} # print the line

Then, either preprocess your data file by command awk -f addblanks.awk <a.dat
or plot the datafile under a unixish platform by gnuplot> splot "<awk -f
addblanks.awk a.dat".

3.11 Drawing a (color) map, i.e. 2D projection of 3D data

Use set view map; unset surface or set pm3d map rather than set view 180,0. The
latter facilitates drawing matrices or data files as maps, even without the
necessity for matrix-like data organization (gridding). It is possible to
decrease the output postscript file size by postprocessing it by
pm3dCompress.awk or pm3dConvertToImage.awk.

Note there is a new plotting style with image for plotting 2D color images with
support for almost arbitrary text or binary files in "Patches" section on
gnuplot's sourceforge site http://www.sourceforge.net/projects/gnuplot/.

3.12 How to overlay dots/points scatter plot onto a pm3d map/surface

Use the explicit (see also implicit) switch of the pm3d style:

gnuplot> set pm3d explicit
gnuplot> splot x with pm3d, x*y with points

3.13 How to draw black contour plot, and contours with labels

Drawing contour plot in one colour requires to write contours into a temporary
file using the table terminal:

set contour base; set cntrparam levels 15; unset surface; set view map
splot x*x+y*y; pause -1
set term table; set out 'contour.dat'
replot; set out; set term pop

Now, for drawing it in 2D, do

reset
plot 'contour.dat' with line -1

end for contours in 3D do

reset
# Change single blank lines to double blank lines
!awk "NF<2{printf\"\n\"}{print}" <contour.dat >contour1.dat
plot 'contour1.dat' with line -1

See also the following question "How to overlay contour plot over pm3d map/
surface".

Labelling contours by their z-value can be achieved by a suitable script
generating automatically the appropriate set label commands; you can find one
at gnuplot scripts page http://gnuplot.sourceforge.net/scripts/index.html#
tricks-here.

3.14 How to overlay contour plot over pm3d map/surface

It is necessary to write contours into a temporary file using the table
terminal, and then use this file in the final drawing without set contours. The
following example demonstrates this for a map; for surface, remove set pm3d map
and put set ticslevel 0.

# Write contours of function  x*x-y*y  to a (temporary) file
set term table
set out 'contour.dat'
set contour base; set cntrparam level 20
unset surface
splot x*x-y*y
set out; set term pop

# Change single blank lines to double blank lines
!awk "NF<2{printf\"\n\"}{print}" <contour.dat >contour1.dat

# Draw the plot
reset
set palette gray
set palette gamma 2.5
set pm3d map
set pm3d explicit
splot x*x+y*y with pm3d, 'contour1.dat' with line -1
!rm contour.dat contour1.dat

The last command deletes the two temporary files.

3.15 Color facets with pm3d

It is possible to draw colors facets of a 3D objects, organized in such a file:

# triangle 1
x0 y0 z0 <c0>
x1 y1 z1 <c1>

x2 y2 z2 <c2>
x2 y2 z2 <c2>


# triangle 2
x y z
...

Notice the positioning single and double blank line. <c> is an optional color.

Then plot it by (either of splot's):

set pm3d
set style data pm3d
splot 'facets.dat'
splot 'facets_with_color.dat' using 1:2:3:4

Note that you avoid surface lines by set style data pm3d or splot ... with
pm3d.

In the above example, pm3d displays triangles as independent surfaces. They are
plotted one surface after another as found in the data file. Parts overlapping
in 2D projection are overdrawn.

Gnuplot is not 3D modeling program. Its hidden routines apply for points and
lines, but not for faces. Without handling the data as a collection of faces,
there would be no surface anything could be hidden behind. The 'hidden3d'
algorithm works by using the input data in two ways: first, to set up a
collection of triangles (made from a mesh of quadrangles) that form the
surface, second as a collection of edges. It then goes through all those edges,
checking what parts of them are not hidden behind any faces, and draws those.

Consequently, gnuplot won't draw your surface or 3D object as a virtual
reality. It works OK for set pm3d map but for true 3D you would be probably
more happy writing a convertor of your facets into a VRML file.

3.16 Palette for printing my color map on color as well as blank&white printer?

I think it is this one, for example: set palette rgbformulae -25,-24,-32. Can
somebody prove this?

4 Wanted features

4.1 What's new in gnuplot 3.7, 4.0 etc?

Too many things to be named here. Please refer to the NEWS file in the source
distribution, or the News section in the gnuplot documentation.

4.2 Does gnuplot support a driver for <graphics format>?

To see a list of the available graphic drivers for your installation of
gnuplot, type set term.

Some graphics drivers are included in the normal distribution, but are
uncommented by default. If you want to use them, you'll have to change file
gnuplot/src/term.h, and recompile.

4.3 Does gnuplot have hidden line removal?

Version 3.7 supports hidden line removal on all platforms; use the command set
hidden3d.

The 16-bit binaries of gnuplot support the hidden line removal only partially
as the hidden-line algorithm may hit the 640k memory limit.

4.4 Does gnuplot support bar-charts/histograms/boxes?

Use the style with boxes for bar charts. To get filled boxes, use set style
fill.

Bernhard Reiter wrote an AWK script to post-process fig-terminal output. Please
have a look at http://www.usf.uni-osnabrueck.de/ breiter/tools/gnuplot/
barcharts.en.html.

There is a large patch (#606169) against the development version on SourceForge
awaiting inclusion in a future release of gnuplot. This adds a new plotting
style with histograms, and supports both clustered histograms and stacked
histograms.

4.5 Does gnuplot support pie charts?

It's not possible in gnuplot, but have a look at http://
www.usf.uni-osnabrueck.de/ breiter/tools/piechart/piecharts.en.html

4.6 Does gnuplot quarterly time charts?

It's not possible in gnuplot, but have a look at http://ricardo.ecn.wfu.edu/
 cottrell/qplot. The corresponding file qplot.zip can be obtained from the
contrib directory on any gnuplot server.

4.7 Can I put multiple pages on one page?

Yes. set multiplot.

If you use the postscript terminal and plot one graph per page you can use the
program mpage (http://www.mesa.nl/pub/mpage) to print multiple logical pages
per physical page. A similar program is the psnup program in the psutils
package. This package is available at any CTAN mirror.

4.8 Does gnuplot support multiple y-axes on a single plot?

Yes. You can have 2 x- and 2 y-axes per plot. The additional axes are called x2
and y2. See help plot.

4.9 Can I put both commands and data into a single file?

This is possible by the new plot "-" possibility. The plot "-" command allows
to read the data to be plot from standard input or the current batch job.

gnuplot> plot "-"
1 1
2 4
3 9
e

4.10 Can I put Greek letters and super/subscripts into my labels?

The enhanced option in some terminals (currently postscript, Presentation
Manager, png, pdf, and x11) lets you use sub- and superscripts. It also allows
to use Greek letters and symbols via symbol fonts, to the extent that these are
supported by the underlying font libraries on your system. Versions through
2.0.15 of libgd (needed for png and jpeg) must be patched in order to handle
symbol fonts.

You might try using the L^ATEX terminal type and putting text like "\\alpha_{3}
" or '\alpha_{3}' . If you include your gnuplot-graphs into a L^ATEX document
you can use the L^ATEX-package psfrag to typeset any characters into your
graphs.

One more possibility is to use the MetaPost terminal. It supports TEX syntax
and is converted onto encapsulated PostScript by mpost.

4.11 How do I include accented characters

To obtain accented characters like u: or n in your labels you should use 8bit
character codes together with the appropriate encoding option. See the
following example:

gnuplot> set encoding iso_8859_1
gnuplot> set title "M\374nchner Bierverbrauch \374ber die Jahre"
gnuplot> plot "bier.dat" u 1:2

Consequently, you can type labels in Czech, French, Hungarian, Russian... by
means of an appropriate set encoding. However, you cannot mix two encodings in
one file (e.g. accents for west and east latin encodings). That you can only do
with a TEX output.

4.12 Can I do 1:1 scaling of axes?

Use set size square.

4.13 Can I put different text sizes into my plots?

Some terminals can, others can't. Some allow you to choose a font size for the
entire plot. Terminals supporting the "enhanced text" mode (like postscript,
pm, x11, png, pdf) allow you to change fonts and text sizes within a plot. Look
at the help for these terminals.

4.14 How do I skip data points?

By specifying ? as a data value, as in

        1 2
        2 3
        3 ?
        4 5

See also set missing. See also set datafile commentschars for specifying
comment characters in data files.

4.15 How do I plot every nth point?

This can be specified with various options for the command plot, for example
plot 'a.dat' every 2.

4.16 How do I plot a vertical line?

Depending on context, the main methods are:

 ・ set arrow .... .... nohead where you have to compute explicitly the start
    and the end of the arrow.
 ・ generate (inlined) datapoints and plot them
 ・ switch to parametric mode

4.17 How do I plot data files

Easily: by a command plot 'a.dat'. In 3D, use splot 'a.dat' - but don't forget
to put a blank line in between two subsequent scans (isolines), otherwise you
will get an error that the data is not gridded; see also question 3.10. If your
data are not gridded, then use set dgrid3d {many options}.

4.18 How do I replot multiplot drawing

You cannot directly: gnuplot supports replot command, not remultiplot. You have
to write the complete sequence of commands since set multiplot till unset
multiplot into a script file. Then you can load the script into gnuplot as many
times as you need for replotting the drawing to different terminals or output
files.

5 Miscellaneous

5.1 I've found a bug, what do I do?

First, try to see whether it actually is a bug, or whether it is a feature
which may be turned off by some obscure set-command.

Next, see whether you have an old version of gnuplot; if you do, chances are
the bug has been fixed in a newer release.

Fixes for bugs reported since the release of the current version are held in
the patches directory at gnuplot distribution sites. Before submitting a bug
report, please check whether the bug in question has already been fixed.

If, after checking these things, you still are convinced that there is a bug,
proceed as follows. If you have a fairly general sort of bug report, posting
to ~comp.graphics.apps.gnuplot is probably the way to go. If you have
investigated a problem in detail, especially if you have a context or unified
diff that fixes the problem, please e-email a report to 
gnuplot-bug@lists.sourceforge.net.

The bug-gnuplot list is for reporting and collecting bug fixes, the  ~
comp.graphics.apps.gnuplot newsgroup will be more help for finding work arounds
or actually solving gnuplot related problems. If you do send in a bug report,
be sure and include the version of gnuplot (including patchlevel) as shown by
the command show version long, terminal driver, operating system, an exact
description of the bug and input which can reproduce the bug. Failure to
indicate these details can render a solution to your problem almost impossible.
Also, any context diffs should be referenced against the latest official
version of gnuplot if at all possible.

5.2 Can I use gnuplot routines for my own programs?

On systems supporting pipes, you can pipe commands to gnuplot from other
programs. Many applications with gnuplot as the graphics engine, like Octave (
http://www.octave.org), uses this method. This also works from a cgi script to
drive gnuplot from a forms-based web page.

John Campbell jdc@nauvax.ucc.nau.edu modified a much earlier version of gnuplot
(3.5) to be a library of C subroutines callable from a C program. Gnuplot
itself has changed radically since then, and we are not aware of any plans to
create a similar library based on the current version.

5.3 What extensions have people made to gnuplot? Where can I get them?

Many extensions or patches are available on the "Patches" page of the gnuplot
development site http://sourceforge.net/tracker/?group_id=2055&atid=302055. The
current development version will generally include some of these being debugged
for inclusion in a later official release of gnuplot.

Older extensions, which may or may not work with the current version, are
available from ftp.ucc.ie in /pub/gnuplot/contrib/.

Some extensions available:

 ・ barchart_via_fig: awk scripts to produce barcharts with filled boxes.
 ・ date-errorbar: allows dates in the hi/lo fields for errorbars.
 ・ perltk: A perl/tk canvas widget.
 ・ polyg.patch: Implements a polygon plotting style.
 ・ xgfe: graphical front end using the Qt widgets available at http://
    www.tug.org/tex-archive/graphics/gnuplot/contrib/.
 ・ Gnuplot.py: A python package to create graphs from within python. More
    information at http://gnuplot-py.sourceforge.net.

5.4 I need an integration, fft, iir-filter,...!

Gnuplot has been and is a plotting program, not a data processing or
mathematical program suite. Therefore gnuplot can't do that. Look into the demo
file "bivariat.dem" for a basic implementation of an integration.

For more sophisticated data-processing read the next section.

5.5 Can I do heavy-duty data processing with gnuplot? or What is beyond
gnuplot?

gnuplot alone is not suited very well for this. One thing you might try is
fudgit, an interactive multi-purpose fitting program written by Martin-D.
Lacasse (isaac@frodo.physics.mcgill.ca). It can use gnuplot as its graphics
back end and is available from ftp.physics.mcgill.ca in /pub/Fudgit/
fudgit_2.33.tar.Z and from the main Linux server, tsx-11.mit.edu and its
numerous mirrors around the world as /pub/linux/sources/usr.bin/
fudgit-2.33.tar.z. Versions are available for AIX, Data General, HP-UX, IRIX 4,
Linux, NeXT, Sun3, Sun4, Ultrix, OS/2 and MS-DOS. The MS-DOS version is
available on simtel20 mirrors (simtel20 itself has closed down) in the "math"
subdirectory as fudg_231.zip.

Carsten Grammes has written a fitting program which has been merged into
gnuplot 3.7.

Michael Courtney has written a program called lsqrft, which uses the
Levenberg-Marquardt - algorithm for fitting data to a function. It is available
from hobbes.nmsu.edu in /pub/os2/apps/analysis/lsqrft15.zip; sources, which
should compile on Unix, and executables for MS-DOS and OS/2 are available.
There is an interface to the OS/2 presentation manager.

You might also want to look at the applications developed by the Software Tools
Group (STG) at the National Center for Supercomputing Applications. Ftp to
ftp.ncsa.uiuc.edu and get the file README.BROCHURE for more information.

You can also try pgperl, an integration of the PGPLOT plotting package with
Perl 5. Information can be found at http://www.ast.cam.ac.uk/AAO/local/www/kgb/
pgperl, the source is available from ftp.ast.cam.ac.uk in /pub/kgb/pgperl/ or 
linux.nrao.edu in /pub/packages/pgperl/.

Another possibility is Octave. To quote from its README: Octave is a high-level
language, primarily intended for numerical computations. Octave is licensed
under GPL, and in principle, it is a free Matlab clone. It provides a
convenient command line interface for solving linear and nonlinear problems
numerically. The latest released version of Octave is always available from 
http://www.octave.org. By the way, octave uses gnuplot as its plotting engine,
so you get a data-processing program on top of gnuplot.

Finally, there is scilab at http://www-rocq.inria.fr/scilab/ doing about the
same as matlab. It is free but copyrighted software.

5.6 Mouse in my interactive terminal does not work

If your mouse is not working, try to hit 'm' in the interactive terminal to
switch mousing on/off. See below for the list of supported interactive
terminals.

If it still does not run, then either gnuplot has not been configured or
compiled with mouse support, or you have not properly installed it, or running
an older version of gnuplot (check your PATH).

If your gnuplot is running as the plotting engine of Octave under X11, then
please put gset mouse into your $HOME/.octaverc. According to gnuplot's help
x11, gnuplot under x11 running through a pipe needs set mouse to be executed
before launching the x11 plot window.

5.7 How to use hotkeys in my interactive terminals

There are several hotkeys available in interactive terminals. Currently the
following interactive terminals support hotkeys and mousing: OS/2 Presentation
Manager, X11, Windows, and GGI. Hit 'h' in the terminal to get list of hotkeys.
See help new or the What is New in 4.0 section in the docs for a brief guide
over mousing and hotkeys. Further, you may read help mouse and help bind for
more information.

5.8 I have ported gnuplot to another system, or patched it. What do I do?

If your patch is small, mail it to gnuplot-beta@lists.sourceforge.net, with a
thorough description of what the patch is supposed to do, which version of
gnuplot it is relative to, etc. Well, please do it always with respect to the
current development version of gnuplot (see 'cvs' above).

Nowadays, the preferred way of submitting, commenting and upgrading patches are
via 'Patches' section on http://www.sourceforge.net/projects/gnuplot/. You may
want to send a note to gnuplot-beta@lists.sourceforge.net for more lively
discussion.

5.9 I want to help in developing the next version of gnuplot. What can I do?

Join the gnuplot beta test mailing list by sending a mail containing the line
subscribe gnuplot-beta in the body (not the subject) of the mail to 
Majordomo@lists.sourceforge.net.

Also check with http://sourceforge.net/projects/gnuplot about latest source for
beta releases for development.

5.10 Open questions for inclusion into the FAQ?

gnuplot-beta@lists.sourceforge.net.

Please submit your questions (along with the answer) to 
gnuplot-beta@lists.sourceforge.net.

6 Making life easier

6.1 How do I plot two functions in non-overlapping regions?

Use a parametric plot. An example:

gnuplot> set parametric
gnuplot> a=1
gnuplot> b=3
gnuplot> c=2
gnuplot> d=4
gnuplot> x1(t) = a+(b-a)*t
gnuplot> x2(t) = c+(d-c)*t
gnuplot> f1(x) = sin(x)
gnuplot> f2(x) = x**2/8
gnuplot> plot [t=0:1] x1(t),f1(x1(t)) title "f1", x2(t), f2(x2(t)) title "f2"

You can also use gnuplot's ability to ignore mathematically undefined
expressions: the expression 1/0 is silently ignored, thus a construction like

gnuplot> set xran [-10:10]
gnuplot> plot (abs(x)>0.5?1/0: x**2)

plots a quadratic function only for |x| < 0.5.

6.2 How do I run my data through a filter before plotting?

If your system supports the popen() function, as Unix does, you should be able
to run the output through another process, for example a short awk program,
such as

gnuplot> plot "< awk ' { print $1, $3/$2 } ' file.in"

The plot command is very powerful and is able to do some arithmetic on
datafiles. See help plot.

The above filtering works seamlessly under Unixes and OS/2. It can work under
MS Windows as well, but that is for experienced users: (A) When gnuplot has
been compiled by cygwin with the unixish way of ./configure; make with X11
terminal instead of the 'windows' terminal. You have to run this under an
X-server. This procedure is out of knowledge for usual users, but powerful for
others. (B) Compile gnuplot yourself by makefile.mgw or makefile.cyg and set
PIPES=1 therein. The drawback is that each wgnuplot.exe will be accompanied by
a boring shell box.

6.3 How do I make it easier to use gnuplot with L^ATEX?

There is a set of L^ATEX macros and shell scripts that are meant to make your
life easier when using gnuplot with L^ATEX. This package can be found on 
ftp.dartmouth.edu in pub/gnuplot/latex.shar, by David Kotz. For example, the
program "plotskel" can turn a gnuplot-output file plot.tex into a skeleton file
skel.tex, that has the same size as the original plot but contains no graph.
With the right macros, the skeleton can be used for preliminary L^ATEX passes,
reserving the full graph for later passes, saving tremendous amounts of time.

6.4 How do I save and restore my settings?

Use the save and load commands for this; see help save and help load for
details.

You can save the current terminal and restore it later without touching the
filesystem by set term push and set term pop, respectively.

6.5 How do I plot lines (not grids) using splot?

If the data in a data file for splot is arranged in such a way that each one
has the same number of data points (using blank lines as delimiters, as usual),
splot will plot the data with a grid. If you want to plot just lines, use a
different number of data entries (you can do this by doubling the last data
point, for example). Don't forget to set parametric mode, of course.

6.6 How do I plot a function f(x,y) that is bounded by other functions in the
x-y plane?

An example:

gnuplot> f(x,y) = x**2 + y **2
gnuplot> x(u) = 3*u
gnuplot> yu(x) = x**2
gnuplot> yl(x) = -x**2
gnuplot> set parametric
gnuplot> set cont
gnuplot> splot [0:1] [0:1] u,yl(x(u))+(yu(x(u)) - yl(x(u)))*v,\
> f(x(u), (yu(x(u)) - yl(x(u)))*v)

6.7 How do I turn off <feature> in a plot?

Most gnuplot features are controlled by a corresponding set/unset command. If a
feature is enabled by default, or by using set <feature>, then you should be
able to turn it by using set no<feature>. However, the prefered syntax in
version 4.0 is unset <feature>.

6.8 How do I call gnuplot from my own programs?

On unix-like systems, commands to gnuplot can be piped via stdin. Output from
gnuplot's print command can be read via a named pipe. On M$ Windows platforms,
due to the lacking standard input (stdin) in GUI programs, you need to use the
helper program pgnuplot which should be included in your gnuplot for M$W
distribution package. Reading gnuplot output may be impossible.

6.9 What if I need h-bar (Planck's constant)?

There is no predefined variable like pi. However to put h-bar as a character
into the label, you must use the PostScript terminal. You can play around with
constructs like @{/=56 -} {/=24 h} or {/=8 @{/Symbol=24 -} _{/=14 h}} In the
latter, the "-" (a long one in /Symbol) is non-spacing and 24-pt. The 14-pt "h"
is offset by an 8-pt space (which is the space preceding the "_") but smaller,
since it's written as a subscript. But these don't look too much like the hbar
we're used to, since the bar is horizontal instead of sloped. I don't see a way
to get that. I tried using an accent (character 264 in iso-latin-1 encoding),
but I haven't found a way to scale and position the pieces correctly.

One more possibility would be {/=14 @^{/Symbol=10 -}{/=14 h}}.

(This is a hint by Richard Crawford).

6.10 How do a produce blank output page?

Well, you probably don't want a blank page, but page with a just a title
(overprinting title in another graph in multiplot page):

reset; unset xtics; unset ytics
unset border; unset key
set title 'Title on an empty page'
plot [][0:1] 2

7 Common problems

7.1 Gnuplot is not plotting any points under X11! How come?

On VMS, you need to make several symbols:

        $ gnuplot_x11 :== $disk:[directory]gnuplot_x11
        $ gnuplot :== $disk:[directory]gnuplot.exe
        $ def/job GNUPLOT$HELP disk:[directory]gnuplot.hlb

Then run gnuplot from your command line, and use set term x11.

If you run gnuplot on Unix systems, be sure that the newest gnuplot_x11 is the
first in your search path. Command which gnuplot_x11 will help you.

7.2 My isoline data generated by a Fortran program is not handled correctly.
What can I do?

Update to the newest gnuplot. Gnuplot 3.7 is able to read Fortran-style files
where a blank line can contain more than a linefeed.

7.3 Why does gnuplot ignore my very small numbers?

Gnuplot treats all numbers less than 1e-08 as zero, by default. Thus, if you
are trying to plot a collection of very small numbers, they may be plotted as
zero. Worse, if you're plotting on a log scale, they will be off scale. Or, if
the whole set of numbers is "zero", your range may be considered empty:

gnuplot> plot 'test1'
Warning: empty y range [4.047e-19:3e-11], adjusting to [-1:1]
gnuplot> set yrange [4e-19:3e-11]
gnuplot> plot 'test1'
              ^
y range is less than `zero`

The solution is to change gnuplot's idea of "zero":

gnuplot> set zero 1e-20

For more information, type help set zero.

7.4 Gnuplot is not plotting on the screen when run from command line via
'gnuplot filename.gp'

Obviously, it draws (unless there is an error in the script file), but the plot
dissappears immediately when the script is completed.

Solution 1: Put a pause -1 after the plot command in the file, or at the file
end.

Solution 2: Use command gnuplot filename.gp - (yes, dash is the last parameter)
to stay in the interactive regime when the script completes.

Solution 3A: On an X-Window System system, you can also use the -persist
option, the X11 window is then not closed. Close the X11 window by typing "q"
when the focus is on it.

Solution 3B: On M$ Windows, you can also use either -persist or /noend.

Solution 4: For OS/2 PM terminal, use set term pm persist or set term pm
server. For X11 terminal, use set term x11 persist.

7.5 My formulas (like 1/3) are giving me nonsense results! What's going on?

Gnuplot does integer, and not floating point, arithmetic on integer
expressions. For example, the expression 1/3 evaluates to zero. If you want
floating point expressions, supply trailing dots for your floating point
numbers. Example:

gnuplot> print 1/3
                0
gnuplot> print 1./3.
                0.333333

This way of evaluating integer expressions is shared by both C and Fortran.

7.6 Set output 'filename' isn't outputting everything it should!

You may need to flush the output with a closing set output.

7.7 When using the L^ATEX-terminal, there is an error during the L^ATEX-run!

Please upgrade to at least gnuplot 3.7. The L^ATEX2$\epsilon$-core no longer
includes the commands "$\backslash$Diamond" and "$\backslash$Box"; 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.

7.8 The exit command does not work as documented!

This is an old bug and is fixed in newer releases.

7.9 I can't find the demos and example files at the URLs in the documentation!

The examples have been removed from the NASA site mentioned in older
documentation. You can currently find the version 3.7 examples at http://
www.gnuplot.vt.edu/gnuplot/gpdocs. Version 4.0 examples are at http://
gnuplot.sourceforge.net/demo.

7.10 Calling gnuplot in a pipe or with a gnuplot-script doesn't produce a plot!

You can call gnuplot by using a short Perl-script like the following:

#!/usr/local/bin/perl -w
open (GP, "|/usr/local/bin/gnuplot -persist") or die "no gnuplot";
# force buffer to flush after each write
use FileHandle;
GP->autoflush(1);
print GP,"set term x11;plot '/tmp/data.dat' with lines\n";
close GP

Gnuplot closes its plot window on exit. The close GP command is executed, and
the plot window is closed even before you have a chance to look at it.

There are three solutions to this: first, use the pause -1 command in gnuplot
before closing the pipe. Second, close the pipe only if you are sure that you
don't need gnuplot and its plot window anymore. Last, you can use the command
line option -persist: this option leaves the X-Window System plot window open.

8 Credits

Gnuplot 3.7's main contributors are (in alphabetical order) Hans-Bernhard
Broeker, John Campbell, Robert Cunningham, David Denholm, Gershon Elber, Roger
Fearick, Carsten Grammes, Lucas Hart, Lars Hecking, Thomas Koenig, David Kotz,
Ed Kubaitis, Russell Lang, Alexander Lehmann, Alexander Mai, Carsten Steger,
Tom Tkacik, Jos Van der Woude, James R. Van Zandt, and Alex Woo. Additional
substantial contributors to version 4.0 include Ethan Merritt, Petr Mikuli'k
and Johannes Zellner.

This list was initially compiled by John Fletcher with contributions from
Russell Lang, John Campbell, David Kotz, Rob Cunningham, Daniel Lewart and Alex
Woo. Reworked by Thomas Koenig from a draft by Alex Woo, with corrections and
additions from Alex Woo, John Campbell, Russell Lang, David Kotz and many
corrections from Daniel Lewart. Again reworked for gnuplot 3.7 by Alexander Mai
and Juergen v.Hagen with corrections by Lars Hecking, Hans-Bernhard Broecker
and other people. Revised for gnuplot 4.0 release by Petr Mikuli'k and Ethan
Merritt.

この文書について...

Gnuplot FAQ

この文書はLaTeX2HTML 翻訳プログラム Version 2002-2-1 (1.70)

Copyright (C) 1993, 1994, 1995, 1996, Nikos Drakos, Computer Based Learning
Unit, University of Leeds,
Copyright (C) 1997, 1998, 1999, Ross Moore, Mathematics Department, Macquarie
University, Sydney.

を日本語化したもの( 2002-2-1 (1.70) JA patch-2.0 版)

Copyright (C) 1998, 1999, Kenshi Muto, Debian Project.
Copyright (C) 2001, 2002, Shige TAKENO, Niigata Inst.Tech.

を用いて生成されました。

コマンド行は以下の通りでした。:
latex2html -split 0 -show_section_numbers -html_version 4.0 -nonavigation
faq.tex.

翻訳は Shigeharu TAKENO によって 2005年 3月 18日に実行されました。
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Shigeharu TAKENO 2005年 3月 18日