Re: [Closed REQ 6258]: question

[daemon]

> I want to plot a 3D graph (plot of pixel value in z axis,
> row and column numbers in x and y axes respectively).

If you have data that fit in some sort of grid -- N rows, M columns,
NxM data points -- then it's very simple: use a MESH.  If (since) the
rows and columns are lined up with the x and y axes, it's even
simpler.  For example, here's a MESH that represents the function
z(x,y) = x + y^2 as x and y go from -1 to 1, x in 5 steps, y in 3 steps.
The comments, line breaks, and so on are just for readability.  All you
need is to separate items with blanks (no commas).

MESH
5 3

# First row of 5 vertices:  
-1	-1	0		# x y z
-.5	-1	.5
0	-1	1
.5	-1	1.5
1	-1	2

# another row...
-1	0	-1
-.5	0	-.5
0	0	0
.5	0	.5
1	0	1

# last row...
-1	1	0
-.5	1	.5
0	1	1
.5	1	1.5
1	1	2

If the data aren't arranged on some sort of rectangularly-connected
grid, but have the form of some function z(x,y) on scattered
points in the x-y plane, you can use scatter2graph (from
  ftp://ftp.geom.umn.edu/pub/software/scatter2graph.tar.Z
) to take the data and make a surface out of them that's
readable by geomview.

Hope this helps.

  Stuart Levy