Gnuplot heatmap XYZ

Question

Hey guys I'm trying to do a real heat map like in A true heat map in R, but in GNUPLOT.

My file is like

3 1 2
3 4 3
3 5 5

4 1 7
4 1 2
4 4 3
4 5 2

5 1 3
5 1 2
5 4 3

.
..
....

and I've tried with

plot "file" using 1:2:3 with image

splot "file" using 1:2:3 p3md

etc..

Also I follow this example http://gnuplot.sourceforge.net/demo/heatmaps.html, but nothing.

Can someone shed some light here please?

Thanks

Answer 1

set pm3d interpolate 2,2
splot "file"

You can adjust level of interpolation by changing the number or even set it as 0 to tell gnuplot to "guess" it. It is not well documented what interpolation method that gnuplot is using, so be careful.

set pm3d interpolate 0,0
splot "file"

Here's the result without interpolation:

Here's the result with interpolation 2,2:

Here's the result with interpolation 0,0:

Answer 2

Use the pm3d option:

set pm3d
splot "file"