How to find the nearest land mark from a given longitude and latitude?

Question

I have a table called osm_places with place_name geometry, place_type and many other info related to the city. My database system is PostGIS.

My requirement is:

Given a latitude and longitude (which may or many not be the exact lat and long stored in the database), I need to find the nearest city or place_name from the table osm_places with the help of the input latitude and longitude. Any help is highly appreciated.

Is there a nearest neighbor implementation in php available for this or SQL to handle this?

Answer 1

There is a function in pgRouting called find_node_by_nearest_link_within_distance(), which does exactly what you need. See http://underdark.wordpress.com/2011/10/11/a-look-at-pgrouting-find_node_by_nearest_link_within_distance/

Answer 2

Geonames API can also do this - you will need an account:

Live Demo http://api.geonames.org/findNearbyJSON?lat=47.3&lng=9&username=demo

Example - but you need to use your own account (replace username=demo) http://api.geonames.org/findNearbyJSON?lat=51.507689&lng=-0.127934&username=demo

Documentation http://www.geonames.org/export/web-services.html#extendedFindNearby