[Gnuplot-info] 2d heatmap and 3d

[Matthias P. <sla...@gm...>]

Hello Gnuplotters!

I have some basic experience with GnuPlot, working on Windows with v4.4.

So far, there's gridded 3D data in a binary file (format: x=short,y=short,z=float32). The data basically looks smth like this:
-100 -100 1.42
-100 -99  2.32
-100 -98  14.22
...
-100 99   2.32
-99 -100  2.58
...

(a 200x200 matrix)

By using a multiplier for x and y when gridding, I am able to scale my graph to any size I like. The gnuplot script is the following:

set size ratio 1
set xrange [-1.52333:1.543333]
set yrange [-1.52333:1.543333]
set zrange [0..200]
set palette rgbformulae 22,13,-21
plot 'datafile.bin' binary format="%short%short%float32" u ($1*0.1):($2*0.1):3 palette w image
pause -1


Is it possible to plot the heatmap without explicit x/y coordinates in binary data file? I'd like to have gnuplot create x/y implicitly from matrix indices. So first value in data file is x,y = (0,0) and second value is (0,1) and so on.
Is it faster to precompute the scaling on z values in a program which creates the binary data file than computing it in Gnuplot? Gnuplot seems to be very slow on my system (Core Duo, E7400, 4 Gig RAM).


Thank you for reading!
Paule
-- 
GMX DSL Doppel-Flat ab 19,99 Euro/mtl.! Jetzt mit 
gratis Handy-Flat! http://portal.gmx.net/de/go/dsl