Gri is a language for scientific graphics applications.  By 'language'
I mean that it is a command-driven application, as opposed to a
click/point application.  It is analogous to latex or tex, and shares
the property that extensive power is the reward for tolerating a
modest learning curve.  Gri output is in industry-standard PostScript,
suitable for incorporation in documents prepared by various text
processors.

Gri can make x-y graphs, contour-graphs, and image graphs.  In
addition to high-level capabilities, it has enough low-level
capabilities to allow users to achieve a high degree of customization.
Precise control is extended to all aspects of drawing, including
line-widths, colors, and fonts.  Text includes a subset of the tex
language, so that it is easy to incorporate Greek letters and
mathematical symbols in labels.

Homepage:
http://gri.sourceforge.net/
