Trying to plot a contour map of a film thickness. The substarte is round.
X/Y coordinates are not in a grid so the data table has several empty cells.
Trying to use 'Tool/Options...', 'Chart' tab and selecting the 'Interpolate'
radio button does nothing. The chart treats the empty cells as zero value.
If it would interpolate I would be happy.

I also tried this with a grid (square) X/Y table with a couple of empty
cells and again, it did not interploate.