Whilst at university, as a geography undergraduate, I was used to hearing the old stereotype that my course was all about ‘colouring in’. Part of me wished it was a case of choosing the right crayons… However, a few years down the line, in the world of geospatial analysis, besides all the fascinating analysis we do, sometimes the basics of picking the right colours is indeed important to make output legible and accessible. Although ArcGIS and other GIS packages provide built in colour transitions and symbologies, sometimes, especially with web development, a surprising amount of time can be taken getting colours correct, whether this be chloropleth maps, print outs or making it colour blindness accessible (see more here from Europa Technologies).
Many of you may already be aware of some of the tools online to assist with this issue, but here is some brief information for the best ones I’ve seen. They all aim to allow you test out colour schemes and provide #HEX colour codes once you have decided.
ColourBrewer 2.0 (http://colorbrewer2.org/)
The most popular tool for ‘colour advice’ is probably ColorBrewer. It is specially designed for cartographers and provides a useful test map window for whatever chloropleth style (multi-hue and single hue) you wish, as well as seeing the effects spread of data and underlying data. Another great advantage is that it has colour blind and print friendly options, where it will remove options that don’t adhere with this. The only downside is that it is hard to see how you can alter the colours, it only seems to allow you to use the preset schemes, though there may be good reason for this.
This isn’t necessarily designed for cartographers, more towards web developers, but it has in my opinion the best interface, giving you a lot of flexibility in choosing multi/single hue spreads, and like all the tools listed, provides option to export the values. There isn’t a test map window like ColorBrewer, however it does allow you to preview the colour themes for template web pages, graphics and animations, as well as factor in different types of colour blindness, 256 colour web pages, gamma saturation and more. In an industry where web development is becoming more relevant for many, it is worth a look.
Colorpicker for data (http://tristen.ca/hcl-picker/)
Finally, this is a bit a wildcard I stumbled upon, but useful open source tool, which in some ways takes some of the best bits of previous two examples. The interface is a simpler, but nonetheless, flexible in a similar way to Paletton, and also provides a different hue types and level of chroma (this makes more sense on the site), and it is easy copy the HEX values and change the number of classes. Although, it doesn’t provide colour blindness and printing checks like ColorBrewer, it does provide a chloropleth map window.
Not the most cutting edge or fascinating element of mapping and GIS, but it is an important consideration and hopefully this may have come in useful. Do you have any other suggestions for this topic? Or anything else? Let me know in the comments.