Question

I am trying to generate a heatmap in R for a dataset, which has a broad value range. The dataset mostly contains zeros which shall be colored white. Most of the remaining value are range between 1 and 200 with a decreasing density. A few values range between 201 and 16000.

I would like to create colored bins for the heatmap in advance, for instance:
0 white
1-20 green
21-70 yellow
71-200 orange
201-16000 red

Any ideas on that?

Thx!

Answer 1

The function heatmap.2 in gplots has built-in breaks definition.

library(gplots)
x <-matrix(c(seq(0,90,10),runif(90,0,16000)),10)
my.breaks <-c(0,1,20,70,200,16000)
my.col=c("white","green","yellow","orange","red")
heatmap.2(x, col = my.col, breaks=my.breaks)