Here is a javascript function: function measure(lat1, lon1, lat2, lon2){ // generally used geo measurement function var R = 6378.137; // Radius of earth in KM var dLat = lat2 * Math.PI / 180 – lat1 * Math.PI / 180; var dLon = lon2 * Math.PI / 180 – lon1 * Math.PI / 180; var … Read more
Another option: Download the cities database from http://download.geonames.org/export/dump/ Add each city as a lat/long -> City mapping to a spatial index such as an R-Tree (some DBs also have the functionality) Use nearest-neighbour search to find the closest city for any given point Advantages: Does not depend on an external server to be available Very … Read more
Update: 04/2018: Vincenty distance is deprecated since GeoPy version 1.13 – you should use geopy.distance.distance() instead! The answers above are based on the Haversine formula, which assumes the earth is a sphere, which results in errors of up to about 0.5% (according to help(geopy.distance)). Vincenty distance uses more accurate ellipsoidal models such as WGS-84, and … Read more