Here I have two 'clusters', and just one legend.
How can I get two "density" legends with two different color gradients?
I have tried group but it does not work.
The following code generated the above graph:
library(ggplot2)
df <- data.frame(x=c(rnorm(1000,1,.1),rnorm(1000,3,.1)),
y=c(rnorm(1000,1,1),rnorm(1000,3,1)),
type=c(rep('a',1000),rep('b',1000)))
plot( ggplot(df) +
stat_bin2d(aes(x,y,fill=..density..,group='type')))