Judy Olson, whose research on the effectiveness of cartographic symbols includes several widely cited studies of color schemes for bivariate maps, provides a concise overview of the decorative and functional uses of color on maps. One of eight visual variables, color is often employed improperly or ineffectively by mapmakers unaware of conventional associations, proven strategies, and the cartographic theory of its use. Olson reviews the appropriate use and relative effectiveness of several color strategies for statistical maps, including qualitative, single-sequence, double-ended (that is, with a light color in the center and darker colors at the ends), shading, and two- and three-variable schemes. She also examines the graphic quality of various display devices, including CRTs, slide generators, large-format filmwriters, pen plotters, ink-jet plotters, scribing and photohead plotters, and laser platemakers.

Given the wide use and misuse of color in computer-generated maps, this short but lucid chapter is an appropriate addition to a book on color and the computer. The references are few but well chosen, and the supporting illustrations included in the tipped-in color-plate insert are visually effective and carefully related to the discussion. The chapter’s principal deficiency is the brevity inherent in an attempt to treat color maps in one of a diverse collection of chapters. Yet the pragmatic focus on a set of guidelines allows Olson to address most of the major blunders perpetrated by amateur or impromptu mapmakers and untrained developers of cartographic software.