the closest I got it this:
I cleared data where region are equals but as heatmap requires continous field it's hard to colormap nulls to black. However, you can try to produce better results using conditional formatting as in my blog post here: Conditional Formatting - meowBi (scaffolding technique).
Find workbook attached.
forum201612272.twbx 17.9 KB
Thanks so much for the great answer and your blog. I did see your blog earlier today and now that you are showing it -- it's meant to be. I'll try the techniques - I'm sure they'll work.
All the best