Gri is an open-source language for scientific graphics programming. It is command-driven, as opposed to point/click. Some users consider Gri similar to LaTeX, since both provide extensive power as a reward for tolerating a learning curve. The output is industry-standard PostScript as output, suitable for inclusion in other documents.

Gri can make x-y graphs, contour graphs, and image graphs. Fine control is provided over all aspects of drawing, e.g. line widths, colors, fonts, etc. Greek letters and mathematical symbols are available in a TeX-like syntax.

Folks who write 1000-line Gri scripts usually start with something as simple as the following:

open file.dat # open a file
read columns x * y # read the 1st column as x and the 3rd as y
draw curve # draw the data and autoscale the axes
A full manual is also available in HTML (gri-html-doc package), in PDF suitable for printing (gri-pdf-doc package) and on-line by following links from the gri home page:
http://gri.sourceforge.net/