Visualization Analysis and Design

Chapter 10

Map Color and Other Channels

10.1 The Big Picture

This chapter covers the mapping of color and other nonspatial channels in visual encoding design choices, summarized in Figure 10.1. The colloquial term color is best understood in terms of three separate channels: luminance, hue, and saturation. The major design choice for colormap construction is whether the intent is to distinguish between categorical attributes or to encode ordered attributes. Sequential ordered colormaps show a progression of an attribute from a minimum to a maximum value, while diverging ordered colormaps have a visual indication of a zero point in the center where the attribute values diverge to negative on one side and positive on the other. Bivariate colormaps ...