plot multiple country maps with fixed size and layout-CodePudding

I am trying to plot a a series of maps (NZ, Australia and Argentina) in a grid, with some parts of the grid being empty. I am using ggplot to create the individual maps and then patchwork to sow together the grid.

I expect the result to be a 3x3 grid with 3x NZ maps on the top row, 2x aus an empty plot on the second row and 1x Argentina 2x empty plots on the 3rd row.

My problem is the plots do not maintain a 3x3 grid and the countries are very different sizes. An example:

library(tidyverse)
library(sf)
library(rnaturalearth)
library(patchwork)


# basic country maps
nz <- ne_countries(country = 'new zealand', type = 'countries', returnclass = "sf")
aus <- ne_countries(country = 'australia', type = 'countries', returnclass = "sf")
arge <- ne_countries(country = 'argentina', type ='countries', returnclass = "sf")

# plot nz
p1 <- ggplot()   
  geom_sf(data = nz)  
  theme_void()

# plot aus
p2 <- ggplot()   
  geom_sf(data = aus)  
  theme_void()

# plot arg
p3 <- ggplot()   
  geom_sf(data = arge)  
  theme_void()


# combine plots
p1   p1   plot_spacer() /
  p2   plot_spacer()   p2 /
  plot_spacer()   plot_spacer()   p3

Whereas the desired output would be like this (with the maps all a similar size):

Any pointers would be much appreciated!

CodePudding user response：

This is a bit of a hack which I use quite often when I have to export maps. The basic idea is to not plot or export the map directly but instead add it to an empty background plot first via patchwork::inset_element.

For the first plot I dropped theme_void from the background plot which shows that all subplots are actually of the same size independent what the size of the map is:

library(tidyverse)
library(sf)
library(rnaturalearth)
library(patchwork)

plist <- dplyr::lst(p1, p2, p3)

plist <- lapply(plist, function(x) {
  ggplot()  
    geom_blank()  
    #theme_void()  
    inset_element(x, left = 0, right = 1, top = 1, bottom = 0)
})

# combine plots
(plist$p1   plist$p1   plist$p1) /
  (plist$p2   plot_spacer()   plist$p2) /
  (plot_spacer()   plot_spacer()   plist$p3)

And here is the final plot using theme_void for the background plots too:

plist <- dplyr::lst(p1, p2, p3)

plist <- lapply(plist, function(x) {
  ggplot()  
    geom_blank()  
    theme_void()  
    inset_element(x, left = 0, right = 1, top = 1, bottom = 0)
})

# combine plots
(plist$p1   plist$p1   plist$p1) /
  (plist$p2   plot_spacer()   plist$p2) /
  (plot_spacer()   plot_spacer()   plist$p3)