Color Schemes for Images and Heat Maps

Description

Creata a vector of N contiguous colors.

Usage

redscale(N)
greenscale(N)
bluescale(N)
blueyellow(N)
redgreen(N)

Arguments

Details

The color maps that ship with R (see, for example, terrain.colors) do not include the most common colors maps found in used in publications in the microarray literature. This collection of color maps expands the available options. The functions redscale, greenscale, and bluescale each range from pure black for low values to a pure primary color for high values.

The redgreen color map ranges from pure green at the low end, through black in the middle, to pure red at the high end. Although this is the most common color map used in the microarray literature, it will prove problematic for individuals with red-green color-blindness.

The blueyellow color map ranges from pure blue at the low end, through gray in the middle, to pure yellowe at the high end.

Value

A character vector 'cv' of color names. This can be used to create a user-defined color palette for subsequent graphics by 'palette(cv)' or directly in a 'col=' specification in 'par' or in graphics functions such as 'image' or 'heatmap'.

BUGS

The names redgreen and blueyellow are inconsistent with respect to which color represents low values and which color represents high values. It is too late to fix this.

Author(s)

Kevin R. Coombes <kcoombes@mdanderson.org>

See Also

rainbow, topo.colors, terrain.colors, heat.colors, rgb, image, heatmap, palette.

Examples

data <- matrix(1:1024, nrow=1024)
image(data, col=bluescale(64))
image(data, col=redgreen(32))
image(data, col=redscale(128))
image(data, col=blueyellow(64))
rm(data) # cleanup