Using Colors in Plots - R Graphics - page 329

Discussion
Changing a palette is a modification of the color (or fill) scale: it involves a change in the map-
ping from numeric or categorical values to aesthetic attributes. There are two types of scales that
use colors: illscales and colorscales.
With scale_fill_hue() , the colors are taken from around the color wheel in the HCL (hue-
chroma-lightness) color space. The default lightness value is 65 on a scale from 0-100. This is
good for filled areas, but it's a bit light for points and lines. To make the colors darker for points
and lines, as in Figure 12-5 (right), set the value of l (luminance/lightness):
# Basic scatter plot
h <- ggplot(heightweight, aes(x = ageYear, y = heightIn, colour = sex)) +
geom_point()
# Default lightness = 65
h
# Slightly darker
h + scale_colour_hue(l = 45 )
Figure 12-5. Left: points with default lightness; right: with lightness set to 45
The ColorBrewer package provides a number of palettes. You can generate a graphic showing
all of them, as shown in Figure 12-6 :
library(RColorBrewer)
display.brewer.all()