XKCD: Bad Map Projection: ABS(Longitude)

gistfile1.txt

# recreation of https://xkcd.com/2807/


library(ggplot2)
library(sf)
library("rnaturalearth")
library("rnaturalearthdata")
# library(lwgeom)

world <- ne_countries(scale = "small", returnclass = "sf") |>
  sf::st_as_sf() %>% 
  sf::st_set_crs(value = 4326) 

ggplot(data = world) +
  geom_sf()

# # https://wilkelab.org/practicalgg/articles/Winkel_tripel.html
# crs_wintri <- "+proj=wintri +datum=WGS84 +no_defs +over"
# world_wintri <- st_transform_proj(world, crs = crs_wintri)
# # https://www.happykhan.com/posts/map-projections-in-r/
# grat_wintri <-
#   st_graticule(lat = c(-89.9, seq(-80, 80, 20), 89.9)) %>%
#   st_transform_proj(crs = crs_wintri)


# ggplot(data = world) +
#   geom_sf() +
#   coord_sf(crs= "+proj=robin") 



world_rev <- st_geometry(world)  * matrix(c(-1,0,0,1), 2, 2) 
world2 <- world |>
  st_set_geometry(world_rev) |>
  sf::st_as_sf() |>
  sf::st_set_crs(value = 4326) 
  

ggplot() +
  geom_sf(data = world) +
  geom_sf(data = world2) +
  coord_sf(xlim = c(0, 180))