CODEWITHSUNDEEP
rggplot2heatmap
djneuron
djneuron

Reputation: 81

Need to create ggplot heatmap with NA-only data, but get "Error: Must request at least one colour from a hue palette."

I need to create one-row heatmap, that occasionally will be derived from NA-only column, but has to be displayed anyway. In the example below generating heatmap from p2 column will render "Error: Must request at least one colour from a hue palette.". Is there any way to force ggplot to display an "empty" heatmap?

library(ggplot2)
id <- letters[1:5]
p1 <- factor(c(1,NA,2,NA,3))
p2 <- factor(c(NA,NA,NA,NA,NA))
dat <- data.frame(id=id, p1=p1, p2=p2)

ggplot(dat, aes(x=id,y="identity")) + geom_tile(aes(fill = p1), colour = "white") #works fine

ggplot(dat, aes(x=id,y="identity")) + geom_tile(aes(fill = p2), colour = "white") #renders error

Upvotes: 3

Views: 302

Answers (1)

Dave Gruenewald
Dave Gruenewald

Reputation: 5689

I think if you explicitly tell ggplot how to handle NA values using the na.value inside a scale_fill_manual call. This should take care of your issue, or at least head you in the right direction:

ggplot(dat, aes(x=id,y="identity")) + 
  geom_tile(aes(fill = p2), colour = "white") + 
  scale_fill_manual(values = "white", 
                    na.value = "black")

You can change the values argument to better handle the colors you like

Upvotes: 5

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