Quick population map

usa_pop.R

library(sf)
library(tidycensus)
library(dplyr)
library(ggplot2)
options(tigris_use_cache = TRUE)

acs_pop <- do.call(
  rbind,
  lapply(
    setdiff(state.abb, c("AK", "HI")),
    \(x) get_acs(
      geography = "block group",
      variables = "B01003_001",
      state = x,
      year = 2019,
      geometry = TRUE,
      cache_table = TRUE
    )
  )
)

usa_pop <- acs_pop %>%
  tidyr::drop_na() %>%
  mutate(in_area = units::drop_units(st_area(.)) * 1e-6,
         estimate = estimate / in_area) 

plot_col <- "#F9F9F9"

usa_pop |> 
  mutate(class = case_when(
    estimate > 10000 ~ 5,
    estimate > 1000  ~ 4,
    estimate > 100   ~ 3,
    estimate > 10    ~ 2,
    TRUE             ~ 1
  ),
  class = factor(class, 
                 levels = 1:5, 
                 labels = c(
                   "[0, 10]",
                   "(10, 100]",
                   "(100, 1,000]",
                   "(1,000, 10,000]",
                   "(10,000, +]"
                   ))) |> 
  ggplot() + 
  geom_sf(aes(fill = factor(class)), color = NA) + 
  scico::scale_fill_scico_d(palette = "lajolla",
                            name = expression("Population per km"^2),
                            guide = guide_legend(title.position = "bottom"),
                            direction = -1) + 
  theme(axis.line = element_blank(),
        axis.ticks = element_blank(),
        panel.grid = element_blank(),
        axis.text = element_blank(),
        axis.title = element_blank(),
        # https://fonts.google.com/specimen/Lato
        text = element_text(family = "Lato", colour = "#191900"),
        strip.background = element_blank(),
        strip.text = element_text(size = 11),
        legend.text = element_text(size = 9),
        legend.title = element_text(hjust = 0, size = 12),
        legend.background = element_blank(),
        legend.spacing = unit(11, "pt"),
        legend.margin = margin(0, 0, 0, 0),
        legend.key = element_blank(),
        legend.key.size = unit(1.1 * 12, "pt"),
        legend.box.margin = margin(0, 0, 0, 0),
        legend.box.background = element_blank(),
        legend.box.spacing = unit(11, "pt"),
        legend.position = "bottom",
        panel.background = element_rect(fill = plot_col, color = plot_col),
        plot.background = element_rect(fill = plot_col, color = plot_col),
        legend.justification = c("center"), 
        legend.key.width = unit(1.7 * 12, "pt"))
ggsave("usa_population.png", width = 16, height = 10, units = "in")