Mapping and Colour blindness

The explosion in spatial data availability and dissemination through online visualisation has produced many interesting maps. A friend of mine, however, recently commented that not enough is done for those with colour blindess.  To see the impact of this I was recommended a great website developed by Stanford University that enables users to check  how clear their images are to colour blind people. I have run this test for a number of maps below.  The top three maps are amongst the most popular maps on CASA’s Maptube Website whilst the fourth map is one of my own. The top two are have undergone the test for Deuteranope colour blindness and the bottom two for Protanope colour blindness.

I was amazed at how indistinguishable seemingly contrasting colours can be. The final map fares best and I think this is because it is simply differing shades of the same colour. If I am honest colour blindness is not something I have seriously considered in my own maps until now so I cannot claim to be a good example. From now on, however, I intend to make a real effort in colour selection for my maps. You can’t go far wrong with the Colorbrewer palettes so I will make the effort to use these as much as possible in the future.

Thanks to Jess Wardlaw for telling me about Vischeck.