Get a country for a longitude / latitude point. World Borders Dataset to be found at http://thematicmapping.org/downloads/world_borders.php

country_detect.py

import rtree
import cPickle
import osgeo.ogr
import shapely.wkb
import shapely.speedups

shapely.speedups.enable()

class FastRtree(rtree.Rtree):
	def dumps(self, obj):
		return cPickle.dumps(obj, -1)

def loader():
	fname = './data/TM_WORLD_BORDERS-0.3.shp'
	
	shapefile = osgeo.ogr.Open(fname)
	layer = shapefile.GetLayer(0)

	for i in range(layer.GetFeatureCount()):
		feature  = layer.GetFeature(i)
		geometry = feature.GetGeometryRef()
		shape    = shapely.wkb.loads(geometry.ExportToWkb())

		obj = {
			'code': feature.GetField('ISO2').lower(),
			'name': feature.GetField('NAME'),
			'shape': shape
		}
		yield (i, shape.bounds, obj)

index = FastRtree(loader())

def detect(point):
	for hit in index.intersection((point.x, point.y), objects="raw"):
		if hit['shape'].contains(point):
			return hit

if __name__ == '__main__':
	points = [
		# lon / lat pairs
		('nl', shapely.geometry.Point(5.389, 52.077)),
		('gb', shapely.geometry.Point(-1.131994, 52.866085)),
		('us', shapely.geometry.Point(-102.743529, 42.077339)),
		('an', shapely.geometry.Point(-68.87, 12.123)),
		('ae', shapely.geometry.Point(54.469813, 23.549000 )),
		('zw', shapely.geometry.Point(29.872, -19.0)),
		('vn', shapely.geometry.Point(105.314, 21.491)),
		('ua', shapely.geometry.Point(31.388, 49.016)),
		('no', shapely.geometry.Point(8.74, 61.152)),
		('li', shapely.geometry.Point(9.555, 47.153)),
		('ma', shapely.geometry.Point(-5.758, 32.706)),
		('es', shapely.geometry.Point(4.166025, 39.904935)),
		('es', shapely.geometry.Point(-16.595450, 28.296571)),
		('sd', shapely.geometry.Point(31.289617, 8.033712)),
		('sd', shapely.geometry.Point(27.773992, 14.728712)),
		('gb', shapely.geometry.Point(-6.811516, 58.000624)),
		('gl', shapely.geometry.Point(-41.560707, 74.720801)),
		('sm', shapely.geometry.Point(12.461467, 43.931073))
	]
	for code, point in points:
		result = detect(point)
		assert result['code'] == code