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rggplot2patchwork

Add legend between patchwork main title and plot titles

Is it possible to have legend below 'main' title' and above plot titles using patchwork?

library(ggplot2)
library(patchwork)

p1 <- ggplot(mtcars, aes(disp, wt, color = factor(gear))) + 
    geom_point() + 
    labs(title = "first plot title")
p2 <- ggplot(mtcars, aes(drat, qsec, color = factor(gear))) + 
    geom_point() + 
    labs(title = "second plot title")

(p1+p2) + 
    plot_layout(guides = "collect") + 
    plot_annotation(title = "main title") & 
    theme(legend.position = "top")

enter image description here

Solution

  • Another way to address this issue is to use the guide_area function within patchwork. The guide area is used to collect all legends if you code it to do so. You can manipulate the guide area as if it is a plot.

    In the example below I added a guide area, placed it in its own row at the top, and then made the relative heights 1:10 so that the guide area takes up less space.

    There are many ways to manipulate a guide area and you may need to adjust the theme as desired to fit different situations.

    p1 <- ggplot(mtcars, aes(disp, wt, color = factor(gear))) + 
  geom_point() + 
  labs(title = "first plot title")

p2 <- ggplot(mtcars, aes(drat, qsec, color = factor(gear))) + 
  geom_point() + 
  labs(title = "second plot title")

guide_area() + (p1+p2) + 
  plot_layout(guides = "collect", 
              nrow = 2, heights = c(1,10)) + 
  plot_annotation(title = "main title") & 
  theme(legend.position = "top")

    enter image description here