In response to an earlier question, there appears to be three popular [free] 3d graphing packages available for linux.
K3Dsurf gnuplot qtiplot
If you are running Ubuntu these are available through the {get software}->{science and engineering}->{math} menu or do an internet search.
Let the group know which one you like.
-- Unka George (George McDuffee) .............................. The past is a foreign country; they do things differently there. L. P. Hartley (1895-1972), British author. The Go-Between, Prologue (1953).