How to keep heatmap colors consistent across datasets

The color of each area in heatmap scenario is calculated using area's value position between lowest and highest available value in your current dataset.

As those vary across different dataset, the same value might produce different color.

To keep value-color pair consistent across all your datasets, all you need to do is to add two "dummy" areas to your data: one with the 0 value, the other with the fixed highest value.

I.e. if your values always fall within 0 and 100, you might want to do something like this to your "areas" in data:

areas: [
  { id: "min", value: 0 },
  { id: "max", value: 100 },
  ...
]