PolyCollection pseudocolor plot smoothing/interpolation/shading (Update: workaround by triangulation)

Right now, PolyCollection can set cell face colors through the set_array method. But it gives patchy results. I have attached an example.

Is it possible to smooth PolyCollection plots, using vertex values + gouraud shading, or ideally using some interpolation available to imshow and NonUniformImage?

Or alternatively, is it possible now or in the near future to make contourf for unstructured mesh data?

Update: 20/05/17:

  • I ended up triangulate the domain (by breaking other polygons into triangles) and use the more versatile tri and tricontourf to get what contour-like results.