Make a square-looking map of U.S. National Parks

national_parks_squared.R

# load libraries
library(tidyverse)
library(rgdal)

# get state data
states_map <- map_data("state") %>%
  # use round to create square border
  mutate_at(.funs = funs(round), .vars = vars(long, lat))

# get park data from https://catalog.data.gov/dataset/national-park-boundariesf0a4c
parks <- readOGR(dsn = "/nps_boundary_shp/", layer = "nps_boundary")

# quick and dirty way to drop parks outside of the continental us
min_lat <- min(states_map$lat)
max_lat <- max(states_map$lat)
min_long <- min(states_map$long)
max_long <- max(states_map$long)

# fortify and edit parks data
parks_f <- fortify(parks) %>%
  filter(long <= max_long & long >= min_long) %>%
  filter(lat <= max_lat & lat >= min_lat) %>%
  # once again use round to create square borders
  # this does some weird things, but i like the effect
  mutate_at(.funs = funs(round), .vars = vars(long, lat))

# make map
ggplot() +
  geom_polygon(data = states_map, aes(x = long, y = lat, group = group), fill = "#343434", alpha = 1, color = "#317873") +
  geom_polygon(data = parks_f, aes(x = long, y = lat, group = group), fill = "lightgrey", color ="lightgrey", size = .75) +
  coord_map("polyconic") +
  theme_void() +
  theme(plot.background = element_rect(fill = "#317873"))