simple solution: store the geohashes and compare prefixes, each prefix length is equivalent to a distance. https://en.wikipedia.org/wiki/Geohash#Digits_and_pre

simple solution: store the geohashes and compare prefixes, each prefix length is equivalent to a distance. https://en.wikipedia.org/wiki/Geohash#Digits_and_precision_in_km https://en.wikipedia.org/wiki/Geohash#Digits_and_precision_i... you can use this pure Elixir library https://hex.pm/packages/geohash https://hex.pm/packages/geohash or this NIF that wraps a much faster C library https://hex.pm/packages/geohash_nif https://hex.pm/packages/geohash_nif or use one of the many geo libraries, like this one https://github.com/yltsrc/geocalc https://github.com/yltsrc/geocalc