graphing software for SGI

[Larry Thorne]

We've just moved several of our people from Suns to Personal Iris machines
(4D/25TGs) and they really miss the graphing/plotting package that they
were using called grtool.  This is about the handiest package to graph/plot
2D data that I've seen, and produces all sorts of output (Postscript, etc.,
etc.).  Unfortunately, it only runs on Suns, but the author is planning to
port it to X.

In the meantime, does anyone know of software that runs on SGI machines that
provides 2D graphing capabilities?   I'm looking for something extremely 
versatile & easy to use that produces Postscript output, can be driven by 
parameter files, etc.
 
PD preferred, but I'm willing to consider others.

Thanks in advance!

Larry Thorne
larryt at ae.msstate.edu