Find County name for a Lat/Long

Question

I\'m trying to find a webservice that will allow me to get a County name (not Country) for a specific Lat/Long. I would be performing the lookup within a server application (li

Answer 1

Another option:

• Download the cities database from http://download.geonames.org/export/dump/
• Add each city as a lat/long -> Country mapping to a spatial index such as an R-Tree (some DBs also have the functionality)
• Use nearest-neighbour search to find the country corresponding to the closest human settlement for any given point

Advantages:

• Does not depend on aa external server to be available
• Much faster (easily does thousands of lookups per second)

Disadvantages:

• May give wrong answers close to borders, especially in sparsely populated areas