Heatmaps can be very powerful to make pairwise comparisons (e.g. when you have a list of scenarios). Unfortunately, we do not have many options for colormaps in BOARD right now, which limits their interpretation. For example, I think I would not be able to create the heatmap below in which I compute the difference btw scenarios as (a-b)/b. Personally, I would also appreciate if we could have a color bar as a legend to interpret the color code.

color example code: colormaps_reference.py — Matplotlib 2.0.2 documentation