I am trying to use griddata to plot some (irregularly) spaced data as a
contour plot, but sometimes ALL the grid it outputs is masked: so no plot.
In the docs I read:
"A masked array is returned if any grid points are outside convex hull
defined by input data (no extrapolation is done)."
but I have no real idea of what does it mean.
Any suggestion to troubleshoot / understand what's going on?