geolocation - Given the lat/long coordinates, how can we find out the city/country?

Question

For example if we have these set of coordinates

"latitude": 48.858844300000001,
"longitude": 2.2943506,

How can we find out the city/country?

Answer 1

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 fast (easily does thousands of lookups per second)

Disadvantages:

• Not automatically up to date
• Requires extra code if you want to distinguish the case where the nearest city is dozens of miles away
• May give weird results near the poles and the international date line (though there aren't any cities in those places anyway