Altitudes heatmap with map overlay?

Hi!
I have a suggestion for an improvement:
With the altitudes.sh heatmap, have output with the map overlay and range - same as the last png from the polar.sh output but instead of signal strength colour, it has altitude colour.

I've been trying to create this myself and making a mess of it without a successful output yet, otherwise I would have given the example here.

Regards,
Cathal.