See Cynthia Brewer's work at http://www.personal.psu.edu/cab38/ColorSch/SchHome.html
Color Use Guidelines for Mapping and Visualization
Cynthia A. Brewer
Click for generalized structure with links to discussion of each color scheme type
The scheme guidelines are limited to the use of color to directly represent data that occur at locations in the graphic where colors occur. The types of thematic maps to which these guidelines apply are choropleth maps (for example, census tracts filled with colors representing the percentage of the population from an ethnic group), filled isoline maps (for example, color bands that mark set ranges of terrain elevation), and qualitative areal-extent maps (for example, different colors for different types of vegetation). My hope is that these guidelines and the associated terminology will also guide the work of people grappling with data visualization challenges in diverse disciplines such as physics, medicine, psychology, and graphic arts.
A disorderly jumble of colors produces a map that is little more than a spatially arranged look-up table. The goal of this WWW resource is to help you do better than that by using color with skill. This resource provides a generalized set of color schemes and example maps.