Great-circle distance between two countries

Haversine distance (km) between two countries' centroids – the lightweight companion to country_borders() for "how far apart" rather than "do they touch". Works from the bundled country_meta centroids, so unlike most of the spatial toolkit it needs neither sf nor the network.

Usage

distance_between(a, b, origin = "country.name")

Arguments

a, b

Vectors of country names or codes. Either the same length, or one of them length 1 to compare one country against many.

origin

How to read a/b (default "country.name").

Value

A numeric vector of great-circle distances in kilometres (NA for any country that doesn't resolve to a known centroid).

Countries without a bundled centroid

country_meta carries no centroid for three territories Natural Earth does not draw at 1:50m (Bouvet Island, Gibraltar and the U.S. Minor Outlying Islands); those inputs return NA here. Kosovo, which countrycode::codelist does not carry, has a curated row with a centroid.

Examples

distance_between("France", "Germany")
#> [1] 802.3525
distance_between("USA", c("Canada", "Mexico"))
#> [1] 2184.930 1622.586