By double clicking any location on Google Map a new distance is calculated. Dist arccos sin lat1 sin lat2 cos lat1 cos lat2 cos lon1 - lon2 R 1. Nautical Miles ACOS sinLat_place_1PI180sinLat_place_2PI180 cosLat_place_1PI180cosLat_place_2PI180.
Currently there are 326 cities in the database or 52975 unique two-way combinations.
Dist arccos sin lat1 sin lat2 cos lat1 cos lat2 cos lon1 - lon2 R 1. Double logitudeDiff MathAbslongitude1Rad - longitude2Rad. Nautical Miles ACOS sinLat_place_1PI180sinLat_place_2PI180 cosLat_place_1PI180cosLat_place_2PI180. Given two points with these coordinates.