Get the distance between two latitude/longitude points in km (example)

Here is a python script to convert lat/lng point to meters. It expects the points to be entered in as decimal degrees. It outputs the distance in km.

For example:

python distlatlng.py 36.12 -86.67 33.94 -118.40
the distance in km is 2887.25995061

#uses the haversine formula
# based on code from http://www.movable-type.co.uk/scripts/latlong.html
import math, sys

def main(*args):
 if len(args) < 5:
  print args[0]," lng1 lat1 lng2 lat2 (finds distance between two lat/lng pairs)"
  return
 lat1 = float(args[1]) 
 lng1 = float(args[2])
 lat2 = float(args[3])
 lng2 = float(args[4])
 radius = 6372.8 # earth's mean radium in km
 dlat = math.radians(lat2-lat1)
 dlng = math.radians(lng2-lng1)
 a = math.sin(dlat/2) * math.sin(dlat/2) + math.cos(math.radians(lat1)) * math.cos(math.radians(lat2)) * math.sin(dlng/2)*math.sin(dlng/2)
 c = 2*math.atan2(math.sqrt(a),math.sqrt(1-a))
 dist = radius*c 
 print "the distance in km is " , dist
 
 
if __name__ == "__main__":
 main(*sys.argv)