Gnuplot Graphics

New releases (3/2000 and later) of unix TSP include a beta test version of gnuplot graphics, with the PLOT and GRAPH commands. (So far, this is available on Sun, linux, IBM RS/6000 and HP-UX). PLOT and GRAPH will still produce the old character plots in the output file by default. To enable the gnuplot graphics, use:

• OPTIONS DISPLAY=X11GNU;
  produces video plots for every subsequent PLOT/GRAPH command, in persistent windows, under Xwindows. To change the default back to character plots, use OPTIONS DISPLAY=NONE; .
  NOTE: the video plots are untested at this time, although I believe the gnuplot commands are correct. It causes use of the -persist flag in the gnuplot command line, and 'set term=x11' in the gnuplot commands.
• PLOT(PREVIEW,...) or GRAPH(PREVIEW,...)
  produces a video plot for just this command.
• PLOT(DEV=GIF,...) or GRAPH(DEV=GIF,...)
  stores a .gif file with the plot image. This plotting mode was used to test all the graphics. (on linux, the .gif file is clipped a little too aggressively). Both PREVIEW and DEV=GIF can be used in the same command.

Example

     smpl 1,10;
     trend t;
     plot(dev=gif) t;

This stores the file plot1.gif with the plot image. While PLOT is executing, the following temporary files are created and eventually deleted: plot1.gpl, plot1.ppm, and T._ .

GIF examples:

• SAMPSEL - 3 local optima
  GRAPH(LINE,TITLE='...',FILE='sampsel',DEV=GIF) RHO LOGL;
  Produced on the Sun, without any clipping problems.
• Grunfeld panel data - fitted values
  FREQ(PANEL,T=20);
  PLOT(TITLE='...',FILE='grun',DEV=GIF) I IPOOL IFIXED;
  Note: for these stacked panel data, there is a break in the line between each individual. This feature was implemented in TSP on 3/9/01.

Required Programs

• gnuplot
  • (tested with gnuplot version 3.5 on Sun (8/93) and Linux (6/98) )
  • The 6/98 "pre 3.6" version allows for a better graph legend (instead of the datafile name). However, this feature is not used by TSP yet.
  • Download location: unknown, but it seems to be commonly installed. (gnuplot was installed on the RS/6000 and HP-UX systems where I updated the TSP ports).
• ppmtogif
  • Required for DEV=GIF, so the large .ppm file can be translated to the compact .gif file. Try "help set term pbm" within gnuplot for more information.
  • A special "silent" version of ppmtogif is included in the linux .zip file with tsp. It omits 2 messages which occur every time the standard version of ppmtogif is run: "ppmtogif: computing colormap..." and "ppmtogif: 3 colors found".
  • We have located binary versions of ppmtogif for Sun, linux, and IBM RS/6000. We haven't looked for one for HP-UX yet.
  • Download location for portable ppmtogif source: ftp://ftp.x.org/contrib/utilities/netpbm-1mar1994.p1.tar.gz

New options for PLOT and GRAPH

• DEV=CHAR/[NONE]/GIF
  DEV=GIF stores a .gif file with the plot image. Once you use DEV=GIF in a PLOT or GRAPH command, it becomes the default for all subsequent PLOT and GRAPH commands. It could be turned off by using DEV=NONE in a later command. If the default FILE=AUTO is used, the .gif files will be named plot1.gif, plot2.gif, .... For DEV=GIF, gnuplot actually creates a (large) temporary .ppm file first, and tsp uses ppmtogif to translate it to a .gif file.
• FILE=[AUTO]/"filename"
  This controls the prefix filenames used for temporary files, and for .gif files. The default FILE=AUTO makes the prefixes plot1, plot2, .... GRAPH(FILE='x_y',DEV=GIF) X Y; would store x_y.gif .
• SAVE/[NOSAVE]
  Use SAVE if you want to modify the gnuplot commands produced by TSP. For example, you could change the line style to linespoints, or make a nicer legend. In the example given above, plot1.gpl and T._ would be saved. plot1.gpl contains the gnuplot commands, and T._ contains the time axis values and T data values. Edit plot1.gpl and use something like the commands:
  gnuplot -persist plot1.gpl
  ppmtogif plot1.ppm > plot1.gif
  rm plot1.ppm

Old options/features supported for PLOT and GRAPH

• TITLE='string'
• GRAPH(LINE)
• GRAPH(PAIR)
• PLOT handles missing values by making a break in the plot line. NOTE: the gnuplot version of PLOT will not run if there are SMPL gaps; you will get a character plot instead.

Thanks to Lars Kristensson of Stockholm University for suggesting the use of gnuplot, and providing a useful shell script to demonstrate it. Other packages, such as Shazam, have used gnuplot for quite awhile.