Selecting effective colors for your maps is a challenge. In Making Maps I review basic color issues, including how we see and create colors, as well as the complexity of color interactions and some basic color guidelines.
A myriad of color resources for mapping exist. A few of the more useful are below.
ColorBrewer: Cindy Brewer and Mark Harrower’s ColorBrewer is a terrific and easy-to-use web-based tool for choosing appropriate color schemes. While the focus is on colors for choropleth maps, the color schemes are appropriate for other map types and information graphics. Color recommendations are displayed on a map (upon which roads, city symbols, and boundaries can be viewed). Icons indicate if the selected color scheme works well for the color blind, if photocopied, or on a computer projector, LCD, or CRT computer screen. Color schemes are specified in five different color models (CMYK, RGB, HEX, LAB, and AV3), making colors easy to transfer to mapping or graphic design software. Color recommendations are based on Brewer’s extensive color research. Requires Flash 5 or later.
Color Oracle: Up to 12% of the population is colorblind. A common form of colorblindness results in red and green looking the same. It’s a problem, then, if you create a map where red and green distinguish different phenomena. Bernhard Jenny and Nathaniel Vaughn Kelso’s Color Oracle is a free software application that simulates three types of color blindness on your computer screen. With your map on screen, start the software and toggle between different kinds of colorblindness to see if your colors work for people with that type of colorblindness. Simple and useful. Mac, Windows, and Linux versions.
Laurie Garo’s Color Theory web pages review diverse color issues in the context of cartography. Includes exercises and additional resources.
Color Palette Generator and Color Hunter generate color schemes from images. Color Palette Generator allows you to submit the URL of an existing image and generate colors that match the image. You can submit the URL to a map you found on the web with a desirable color scheme and generate a palette of similar colors (in HEX, which is the way color is specified in HTML). Color Hunter contains a myriad of color schemes generated from images. Search for “map” for color schemes that may work on maps (again, specified in HEX).
Color Blender generates a series of related colors from a single color you submit to the site.
Adobe’s Kuler site allows you to create, view, and share color schemes. Like with ColorBrewer, colors are specified in common color models (CMYK, RGB, HEX, LAB) that can be easily used in most mapping and graphic design software.
Various color conversion sites are useful for converting colors from one model to another.
On the cultural connotations of color, see Wikipedia’s Color Symbolism and Psychology.
On a myriad of human issues related to color, see the Color Matters web site.
ColourLovers Blog covers a diverse range of color topics.
Or, ditch the computer and generate your color maps with watercolor and colored pencils, like the maps made by McElfresh Map Company.
Let me know of any other color resources you find especially useful for mapping.