Gnuplot

Gnuplot is a versatile program which can generate two- and three dimensional plots of functions and data. The program runs on all major computers and operating systems and can produce output either on screen or as graphics file in many formats.

The program is distributed under a free software license which permits the copying and modification of the source code. Modified versions are only allowed to be distributed as patch files. The program has no connection to the GNU project and does not use the GPL copyleft license.

The program can be used interactively and comes with extensive online help. The user issues text commands in order to produce the plot. It is also possible to write gnuplot scripts which, when executed, generate a plot. For an example script, see logarithmic spiral.

Gnuplot is used as the plotting engine of GNU Octave.

External links:

• Gnuplot Central, contains links to the FAQ and to download locations: http://www.gnuplot.info/
• Gnuplot demo plots: http://www.gnuplot.info/gnuplot/gpdocs/