CODEWITHSUNDEEP
rggplot2na
lydia_english
lydia_english

Reputation: 33

ggplot2: geom_point is sometimes removing NA values depending on the aesthetic used

I'm plotting correlation coefficients r and sample sizes n from a correlation matrix on the same plot (r in the upper triangle, n in the lower triangle). Usually I have no issue with ggplot2 removing my NAs before plotting, but in this situation it's only removing NA values some of the time and I don't know why. I'm using version 3.2.1 of ggplot2.

An example dataframe: 

library(ggplot2)
library(dplyr)

ex <- data.frame(x1 = c(rep("2010", 3), rep("2011", 3), rep("2012", 3)),
                 x2 = rep(c("2010", "2011", "2012"), 3),
                 r = c(NA, 0.5, 0.2, NA, NA, 0.1, NA, NA, NA),
                 n = c(NA, NA, NA, 25, NA, NA, 70, 50, NA))

When I run this graph, with size as an aesthetic, NAs are automatically removed from both geoms: 

ex %>%
  ggplot(aes(x1, x2))+
  geom_point(aes(size = r))+
  geom_text(aes(label = n))

But, when I run this graph, with color as an aesthetic, NAs are only removed from geom_text, not geom_point:

ex %>%
  ggplot(aes(x1, x2))+
  geom_point(aes(color = r), size = 6)+
  geom_text(aes(label = n))

This stackoverflow question, isn't applicable because I do not want to filter out rows. I also tried changing x1, x2, and r to a character based on this, but it didn't work either 

ex %>%
  ggplot(aes(as.character(x1), as.character(x2)))+
  geom_point(aes(color = as.character(r)), size = 6, na.rm = T) +
  geom_text(aes(label = n))

Is there a way to make the color aesthetic ignore NAs?

Upvotes: 3

Views: 1912

Answers (1)

George Savva
George Savva

Reputation: 5336

You can set the na.value value for colour scales. If you set it to NA then the missing points aren't shown:

ex %>%
  ggplot(aes(x1, x2))+
  geom_point(aes(color = r), size = 6)+
  geom_text(aes(label = n)) + 
  scale_color_gradient(na.value = NA)

ggplotwithnacolour

Upvotes: 3

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