R ggplot2 - How do I specify out of bounds values' colour

Question

In the plot generated by the following code I would like to alter the colours so that all values < 0.6 are the same as the \"low\" colour and all values greater than 1 ar

Answer 1

Try changing geom_tile to below:

  geom_tile(aes(fill = ifelse(value<0.6,min(m$value,na.rm=TRUE),
                              ifelse(value>1,max(m$value,na.rm=TRUE),
                                     value))))

EDIT: Then don't use min max, so we will get 0.6-1 range:

geom_tile(aes(fill = ifelse(value<0.6,0.6,
                            ifelse(value>1,1,
                                   value))))

Answer 2

As you said youself, you want the oob argument in the scale_fill_gradient. To clamp values, you can use squish from the scales package (scales is installed when ggplot2 is installed):

library(scales)

and later

scale_fill_gradient(low = "red", high = "green", limits=c(0.6, 1), oob=squish)