circle packing

R code of the ggplot2 example

library(ggplot2)
library(dplyr)
library(gapminder)
library(ggraph)
library(tidygraph)

## A three-level tree: the world, its continents, their countries.
countries <- gapminder |>
  filter(year == 2007) |>
  transmute(name = as.character(country), continent, pop) |>
  arrange(continent, desc(pop))
nodes <- bind_rows(tibble(name = "World", pop = 0),
                   tibble(name = levels(countries$continent), continent = levels(countries$continent), pop = 0),
                   countries)
edges <- bind_rows(tibble(from = "World", to = levels(countries$continent)),
                   tibble(from = as.character(countries$continent), to = countries$name))
world <- tbl_graph(nodes = nodes, edges = edges, node_key = "name")

## Countries of over 200 million people are named.
p <- ggraph(world, layout = "circlepack", weight = pop) +
  geom_node_circle(aes(filter = depth == 2, fill = continent), colour = "white", linewidth = 0.2) +
  geom_node_circle(aes(filter = depth == 1), colour = "#535353", linewidth = 0.3) +
  geom_node_text(aes(filter = depth == 2 & pop > 2e8, label = name), size = 2.4) +
  scale_fill_manual(values = continent_colors) +
  coord_equal() +
  labs(title = "Two countries outnumber whole continents in population",
       subtitle = "142 countries in 2007, circles sized by population",
       fill = NULL,
       caption = "Data: Gapminder, via the gapminder R package") +
  theme_lex_viz(grid = "", arrows = "") +
  theme(legend.position = "right", axis.text = element_blank(), axis.title = element_blank())