Hello :)

I try to represent the galactic dust in our galaxy with a program in C language. My program works and now I want to do this but I didn't succeed with Gnuplot. Is it possible ?

I want to see the value of the quantity of dust in each "box".

Thank you

Sorry for my bad english.

a = 10    # or whatever
b = 5
f(x,y) = a*x + b*y
set view map
set xrange
set yrange

splot f(x,y) with pm3d

# if you like to have lines also

splot f(x,y) with pm3d, f(x,y) with lines lc rgb "black" notitle

Thank you for the answer !

But I'm sorry, I my explication was not good.

In my program, I have a loop and I put the value of f(x,y) in a file (x and y are in the file too).
I tried:

splot "namefile.txt" with pm3d
set view map
replot

and I have nothing in my plot (no color, no value) but the axis are correct.

Thank you

See the demo for heat maps:
http://gnuplot.sourceforge.net/demo/heatmaps.html