Country code from a latitude longitude position (without using geocoding services)

Question

How can i get the country code from a latitude longitude position?

I know that there are many geocoding services available, but they don\'t meed my requirement becau

Answer 1

Given the number of countries (polygons) in the world, you may want to subdivide the set of country polygons to do a rough filter first (e.g., if the point is in the western and northern hemispheres, only need to check North American, Central American, and Carribean countries. That may give you a speed improvement.

Also, keep in mind that many countries consist of multiple polygons, just keep that in mind as you code.

I haven't used any of these sources for country boundary data, but checkout: http://geocommons.com/overlays/33578 and http://geospatial.edublogs.org/2010/06/29/world-country-boundary-files/