[Matplotlib-users] pcolor in action...

[Peter G. <pgr...@ge...>]

Hello Everyone:

Before I reinvent the wheel, I'd thought I'd ask:

I have a set of x,y points in a plane, and to each a corresponding z. 
They are spread out in circular concentric orbits.
I need to do a flat surface plot (via pcolor) of these z values. A 
simple algorithm would be:

#get data for x, y, z.. this would be some fixed points x,y inside
#a box -4<=x<=4 and -4<=y<=4 with a z value for each.

#Create a grid
xi=linspace(-4,4,200)
yi=linspace(-4,4,200)
[Xi,Yi]=meshgrid(xi,yi)

# This is the key step; find a z value for each grid point.
Zi=griddata(x,y,z,Xi,Yi)

pcolor(Xi, Yi, Zi, shading='flat')

show()

The key here is this griddata function. It interpolates the surface at 
the grid points based on the few data points I provide it with (x,y,z). 
It uses Delaunay triangulation, and is part of the standard MATLAB 
distribution (more about it here: 
http://www.mathworks.com/access/helpdesk/help/techdoc/ref/griddata.html#1007265). 
My question is whether anyone has come across its implementation in 
python. I could not find any information in any of the "standard" math 
packages. How do people do this?

Thanks,
Peter