Re: [Gnuplot-py-users] 2d arrays containing z values using gnuplot in python

[Michael H. <mh...@al...>]

Hi,

The problem is a little bit obscure.  You are passing splot() a 2-D 
array, but it really wants a 3-D array (the third axis would accomodate 
multiple data at each (x,y) point.  Probably this should be handled 
better, but a solution for you is to add a third axis explicitly:

     g.splot(a[..., N.NewAxis])

At least that works for me.

Michael

Mark Thomas wrote:
> I have been producing 2d arrays in python containing z values that I would
> like to plot then turn into animated gifs. Up until now I have been using
> gist (pli) to plot them. However, gist is very limited in the output file
> formats and I can't get any of the output file formats into for example
> Python Imaging Library in order to make animated gifs. So I decided to try
> drawing plots with Gnuplot in python. I have tried various examples that
> work in gnuplot but not when I try to put them into python.
> 
> An example is below (adapted from
> http://gnuplot.sourceforge.net/demo/pm3d.html):
> 
> 
> import Gnuplot
> import numarray as N
> g = Gnuplot.Gnuplot(debug=1)
> # set terminal png transparent nocrop enhanced font arial 8 size 420,320
> # set output 'pm3d.9.png'
> g('set border 4095 lt -1 lw 1.000')
> g('set view map')
> g('set samples 30, 30')
> #g('set isosamples 30, 30')
> g('unset surface')
> g('set style data pm3d')
> g('set style function pm3d')
> g('set ticslevel 0')
> g('set title "colour map, using default rgbformulae 7,5,15 ... traditional
> pm3d (black-blue-red-yellow)" 0.000000,0.000000  font ""')
> g('set xlabel "x" 0.000000,0.000000  font ""')
> g('set xrange [0:30] ')
> g('set ylabel "y" 0.000000,0.000000  font ""')
> g('set yrange [ 0:30]')
> g('set y2range [ * : * ] reverse nowriteback  # (currently
> [-10.0000:10.0000] )')
> g('set zrange [ 0.0001 : 1.00000 ] noreverse nowriteback')
> g('set pm3d at b')
> 
> 
> a = N.zeros([30,30]) +.3
> a[5:10,1:22] = .9
> g.splot(a)
> 
> Any thoughts would be greatly appreciated.