在ggplot R中使用边框可自定义pch时，如何使geom_errorbar（）与点的填充颜色相同？

Question

I'm using the special pch (21-25) to make a scatter plot with ggplot since I want the fill of the points to vary with factor levels, but I also want the border of the points to be fixed as black. I wish to add an error bar to each of the points and I want the error bar to be the same color as the fill of the points. However, since I'm fixing the colour aesthetic of points to black and geom_errorbar() uses this to plot the color of the error bars I can't seem to figure out how to get the result I want.

Here is a simple example where I'm getting the undesired result (black color in the error bars):

library(ggplot2)
test <- cbind.data.frame(
  x = rnorm(10),
  y = rnorm(10),
  stdv = sd(rnorm(10)),
  fl = c(rep("foo", 5), rep("bar", 5))
)

ggplot(data = test, aes(x = x, y = y, colour = fl, fill = fl, ymin = y - stdv, ymax = y + stdv)) +
  geom_point(shape = 21, size = 3) +
  scale_colour_manual(values = rep("black", nrow(test))) +
  geom_errorbar()

Answer 1

You can try with new_scale_color() from ggnewscale package (for sure this a trick I learnt from @AllanCameron ):

library(ggplot2)
library(ggnewscale)
#Data
test <- cbind.data.frame(
  x = rnorm(10),
  y = rnorm(10),
  stdv = sd(rnorm(10)),
  fl = c(rep("foo", 5), rep("bar", 5))
)
#Plot
ggplot(data = test, aes(x = x, y = y,
                        colour = fl, 
                        fill = fl,
                        ymin = y - stdv,
                        ymax = y + stdv)) +
  geom_point(shape = 21, size = 3) +
  scale_colour_manual(values = rep("black", nrow(test))) +
  new_scale_color()+
  geom_errorbar(aes(color=fl))

Output:

Answer 2

Any reason you're using scale_colour_manual() instead of just using colour = "black" ? If your actual example allows you to use that, then, you don't need ggnewscale:

library(ggplot2)
test <- cbind.data.frame(
  x = rnorm(10),
  y = rnorm(10),
  stdv = sd(rnorm(10)),
  fl = c(rep("foo", 5), rep("bar", 5))
)

ggplot(data = test, aes(x = x, y = y, colour = fl, fill = fl, ymin = y - stdv, ymax = y + stdv)) +
  geom_point(shape = 21, size = 3, colour = "black") +
  geom_errorbar()

^{Created on 2020-12-11 by the reprex package (v0.3.0)}