I tried implementing the formula in Finding distances based on Latitude and Longitude. The applet does good for the two points I am testing: Yet my code is not working. from math import sin, cos, sqrt, atan2 R = 6373.0 lat1 = 52.2296756 lon1 = 21.0122287 lat2 = 52.406374 lon2 = 16.9251681 dlon = lon2 - lon1 dlat = lat2 - lat1 a = (sin(dlat/2))**2 + cos(lat1) * cos(lat2) * (sin(dlon/2))**2 c = 2 * atan2(sqrt(a), sqrt(1-a)) distance = R * c print "Result", distance print "Should be", 278.546 It returns the distance 5447.05546147. Why? Continue reading...