color.scale {plotrix} | R Documentation |
Transform numeric values into colors.
color.scale(x,redrange,greenrange,bluerange)
x |
a numeric vector, matrix or data frame |
redrange,greenrange,bluerange |
color ranges into which
to scale x |
color.scale
calculates a sequence of colors by a linear
transformation of the numeric values supplied into the ranges
for red, green and blue. If only one number is supplied for a
color range, that color remains constant for all values of x
.
If more than two values are supplied, the x
values will be
split into equal ranges (one less than the number of colors) and
the transformation carried out on each range. Values for a color
range must be between 0 and 1.
A vector or matrix of hexadecimal color values.
The function is useful for highlighting a numeric dimension or adding an extra "dimension" to a plot.
Jim Lemon
# go from green through yellow to red with no blue x<-rnorm(20) y<-rnorm(20) # use y for the color scale plot(x,y,col=color.scale(y,c(0,1,1),c(1,1,0),0),main="Color scale plot", pch=16,cex=2)