Modern maps with sf & projections

The legacy maps polygons are an unprojected plate carrée: they badly distort area and split Russia, Fiji and New Zealand across the antimeridian. The sf backend fixes all of this — real projections, equal-area options, and an antimeridian-safe pipeline. These features require the optional sf and rnaturalearth packages.

install.packages(c("sf", "rnaturalearth", "rnaturalearthdata"))

An equal-area, projected choropleth

world_data(2020, c(gdp = "NY.GDP.PCAP.KD"), geometry = "sf") |>
  world_map(gdp, style = "quantile", projection = "equal_earth",
            title = "GDP per capita (Equal Earth projection)")

world_map() auto-detects the sf backend and applies the projection through ggplot2::coord_sf(). Available projections include "equal_earth" (the default — equal-area and good-looking), "robinson", "mollweide", "natural_earth" and "plate_carree".

Just the canvas

world_geometry() returns projected, region-subset, antimeridian-safe geometry without any data — country polygons, label-ready centroids, coastlines, a graticule or an ocean rectangle:

africa <- world_geometry("countries", geometry = "sf", region = "Africa",
                         projection = "equal_earth")
ggplot(africa) +
  geom_sf(fill = "grey85", colour = "grey40", linewidth = 0.1) +
  theme_world_map()

The live sf map is not shown because sf is not installed in this build.

Recentring and the antimeridian

A Pacific-centred world is one argument away; the sf pipeline runs sf::st_break_antimeridian() before projecting, so nothing streaks across the frame:

world_geometry("countries", geometry = "sf", recenter = 150)

Region subsetting

region accepts a continent, a group name ("EU", "OECD", …), a vector of iso3c codes, or a bounding box c(xmin, ymin, xmax, ymax), and picks a sensible projection for it.

Simplifying for the web

High-resolution geometry can be thinned for fast plotting with simplify_geometry() (which uses rmapshaper when available).

world_geometry(geometry = "sf", scale = "large") |>
  simplify_geometry(keep = 0.1)