我以前写过一个很棒的灵活函数来做这件事。
color.bar <- function(lut, min, max=-min, nticks=11, ticks=seq(min, max, len=nticks), title='') {
scale = (length(lut)-1)/(max-min)
dev.new(width=1.75, height=5)
plot(c(0,10), c(min,max), type='n', bty='n', xaxt='n', xlab='', yaxt='n', ylab='', main=title)
axis(2, ticks, las=1)
for (i in 1:(length(lut)-1)) {
y = (i-1)/scale + min
rect(0,y,10,y+1/scale, col=lut[i], border=NA)
}
}
那么你可以这样做:
> color.bar(colorRampPalette(c("light green", "yellow", "orange", "red"))(100), -1)
更多示例请参见:http://www.colbyimaging.com/wiki/statistics/color-bars