def haversine(lon1, lat1, lon2, lat2):
<EOL>lon1, lat1, lon2, lat2 = map(radians, [lon1, lat1, lon2, lat2])<EOL>dlon = lon2 - lon1<EOL>dlat = lat2 - lat1<EOL>a = sin(dlat / <NUM_LIT:2>)**<NUM_LIT:2> + cos(lat1) * cos(lat2) * sin(dlon / <NUM_LIT:2>)**<NUM_LIT:2><EOL>c = <NUM_LIT:2> * asin(sqrt(a))<EOL>r = <NUM_LIT>  <EOL>return c * r<EOL>
Calculate the great circle distance between two
points on the earth (specified in decimal degrees)