Why do geom_density_2d_filled and geom_contour_filled return a discrete colour scale?

tidyverse
1

This seems inconsistent with the way the rest of ggplot works when a numeric variable is coloured.

library(tidyverse)
ggplot(faithful, aes(x = eruptions, y = waiting)) +
  geom_density_2d_filled()

image
image612×474 14.9 KB

2

I think it is consistent with the concept of contours, because contours are discrete regions of commonality and I'd expect a discrete scale to accompany that.

3

But if you do this...

library(tidyverse)
ggplot(faithful, aes(x = eruptions, y = waiting)) +
  geom_density_2d()

image
image780×454 17.4 KB

4

I cant reproduce your image from that code; I see a single common blue color.

image
image574×462 7.88 KB

5

Oh sorry, add this to the geom

aes(col = after_stat(level))

6

source : ggplot2 3.3.0 (tidyverse.org)
try adding + guides(color=guide_colorsteps())

library(tidyverse)
ggplot(faithful, 
       aes(x = eruptions, y = waiting,
           col=after_stat(level))) +
  geom_density_2d() + guides(color=guide_colorsteps())

image
image574×462 8.77 KB

theres a show.limits = TRUE option you can pass to guide_colorsteps() if you want