Question:
Is there a guideline for how to use multipel linear colormaps in one visualization?
ColorBrewer diverging color scheme seems to work if you want to use only two separate linear colormaps link.
But is it possible to use more than two that are still easily distinguishable?
To be clear, I’m talking about mixing the color spaces in the visualization.
There are tertiary colormaps that can be used if your data consists of three values that sum to 1 at each data-point (for example, the proportion of people <= 14, 15-64, and >65 in each country), but I don’t think that their performance has been very well investigated.
There is some discussion in this Twitter thread.
There are also color scales designed to represent both values and uncertainties (e.g., VSUP, a Value-Suppressing Uncertainty Palette which encodes value with the Viridis color map, and uncertainty with lightness and saturation).
You should also consider using a glyph that is able to represent multiple dimensions as an alternative solution to your problem.
Hi Timon:
I read your inquiry about multiple color maps with great interest. The easiest way to use multiple color maps in a single visualization is to use a series of sequential “single hue” colors maps as shown in ColorBrewer at:
http://colorbrewer2.org/#type=sequential&scheme=Blues&n=8. The challenge with using multiple diverging or even multiple “multi hue” colormaps is that a single particular hue could have double or even multiple meanings at different places in the visualization.