Color Use Guidelines for Mapping and Visualization

I have presented a comprehensive set of color scheme types and corresponding guidelines for the use of hue and lightness for each scheme (Fig. 7.2): The schemes are matched with parallel conceptualizations of data. Examining data with different schemes may reveal different characteristics of distributions and their interrelationships. Software that allows interactive switching between scheme types will facilitate accurate and thorough understanding through data visualization. Random or perceptually ill-fit assignments of colors to combinations of two variables remains a possible “solution” to mapping problems. This solution, however, will mask the interrelationships that the map-maker should be attempting to illuminate by mapping variables together. Better results would be produced by comparing maps of the individual variables (displayed with suitable schemes). The characteristics of both distributions will be rendered indecipherable by failing to organize hue, lightness and saturation in a way that corresponds with logical orderings within the mapped variables. A disorderly jumble of colors produces a map that is little more than a spatially arranged look-up table. The goal of this chapter is to help you do better than that by using color with skill.