Error: continuous value supplied to the discrete scale

Question

I am trying to make a thermal graph for discrete results (each value uses a single color), so that:

df<-data.frame(x=rep(LETTERS[1:10], each=10), y=rep(1:10,10), value=sample(1:8, 100,replace=T)) colors<-c("green", "lightyellow", "yellow", "orange", "orangered", "red", "darkred", "black") ggplot(df, aes(x=x, y=y))+ geom_tile(aes(fill=value), colour="white")+ #scale_fill_gradient(low="green", high="red") scale_fill_manual(values=colors) Error: Continuous value supplied to discrete scale 

Does anyone know how to fix it and apply a color variable to a heat map?

Answer 1

If you want to supply colors manually, you need to map fill to a factor variable.

 ggplot(df, aes(x=x, y=y))+ geom_tile(aes(fill=factor(value)), colour="white")+ scale_fill_manual(name = "Values", values=setNames(colors, 1:8))