xyz points and magnitude to intensity or colormap or contourmap

hi!
how do you do contour maps with vtk?
i have 3600 points for each point i have a corresponding magnitude.
i plane to do contour maps that is i plot each point
with a different color (representing its magnitude )
how can i do this with using python, matplotlib or vtk?
does any one have a similar example
please any thing to start wiht wil be good
thanks

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