Paginate a faceted graph and save as a single multi-page PDF


July 1, 2023

When you have a plot with just a few facets, it’s easy to fit them all on a single page. But what if you have a whole bunch of facets that you want to visualize? For example, the USArrests dataset has data from all 50 US states.

If we just use the usual facet_wrap or facet_grid from ggplot2, you end up with one massive, smooshed-together image:


plot_1 <- USArrests |>  # dataset on US arrests
  rownames_to_column("State") |>   # This is just so we can see the state names
  ggplot(aes(x = UrbanPop, y = Murder)) +
  geom_point()  +
  facet_wrap(~ State,
             nrow = 5, ncol = 10)


The ggforce library, among its many useful functions, includes facet_wrap_paginate and facet_grid_paginate. These work like facet_wrap and facet_grid, but take an additional page argument. Here we specify that we want 4 rows and 5 columns per page, so for 50 states there will be 2 full pages plus one page with the remaining 10 states:


plot_2 <- plot_1  +
  facet_wrap_paginate(~ State,
             nrow = 4, ncol = 5, page = 2)


Note that we had to specify which page we wanted to print. We can then easily put this into a loop to generate all the necessary pages. The helpful n_pages() will count the pages needed, which we can then use in a loop. This gives us 3 separate plots.

plot_pages <- plot_2 |> 

for (i in 1:plot_pages) {
    plot_1 + facet_wrap_paginate(~ State,
             nrow = 4, ncol = 5, page = i)

That’s better, but for inclusion in a longer document or for sharing the plot, you may want all three pages in a single PDF. This can be accomplished by calling pdf() before the loop and after.1

pdf('many_plots.pdf', width = 11, height = 8.5) #start building pdf
  for (i in 1:plot_pages) {
    print( # don't forget this
      plot_1 +
      facet_wrap_paginate(~State, nrow = 4, ncol = 5, page = i)
  } # end building pdf

The resulting PDF is a single file with 3 pages, as we expect.

(This post was inspired by this conversation on StackOverflow.)


  1. In the past I’ve had issues with getting pdf() to work, especially if I use any fancy fonts in the ggplot theme. If you run into issues, you can replace pdf() with cairo_pdf(..., onefile = TRUE), which seems to work even with exotic fonts.↩︎