distance between 2 coordinates

distcompute.py

import math

def distance(origin, destination):
    #assumes origin and destination are (lat, long) pairs where lat and long are decimals
    lat1, lon1 = origin
    lat2, lon2 = destination
    #radius = 6371 # km  <-- use this if metric
    radius = 3961 # miles <-- use this if english / miles
    dlat = math.radians(lat2-lat1)
    dlon = math.radians(lon2-lon1)
    a = math.sin(dlat/2) * math.sin(dlat/2) + math.cos(math.radians(lat1)) \
        * math.cos(math.radians(lat2)) * math.sin(dlon/2) * math.sin(dlon/2)
    c = 2 * math.atan2(math.sqrt(a), math.sqrt(1-a))
    d = radius * c
    return round(d,1)