[pstricks] Map contours plot PStricks

[Henry Proudhon]

Hello,

I want to plot a simple map contours with PStricks and I was wondering if
something exists for this. I explain :

My datas are like x,y,value where value=0,1 or 2
x,y define nodal coordinates between a rectangle region (xstart,ystart) and
(xendyend)

I want to plot countours gathering all 0 values, all 1 values and all 2 values.

I think I can do it by programming a voronoi algorithm but if something already
exists...

Thank you so much for infos...

Henry