Authors: Achim Zeileis, Kurt Hornik
Title: Choosing Color Palettes for Statistical Graphics
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Statistical graphics are often augmented by the use of color
coding information contained in some variable. When this involves
the shading of areas (and not only points or lines) - e.g., as in
bar plots, pie charts, mosaic displays or heatmaps - it is important
that the colors are perceptually based and do not introduce optical
illusions or systematic bias. Here, we discuss how the
perceptually-based Hue-Chroma-Luminance (HCL) color space can be
used for deriving suitable color palettes for coding categorical
data (qualitative palettes) and numerical variables (sequential
and diverging palettes). All palettes are provided in the R package
vcd using the HCL implementation from the colorspace package.