geo location distance

geo_location.py

import sys, math


def get_bin(lat, lng):
    '''bin position'''
    lat = max(0, lat + 70) if lat < 0 else min(140, lat + 70)
    lng = lng + 180

    return int(2 * lat) + 280 * int(2 * lng)


def calculate_distance(lat1, lng1, lat2, lng2):
    '''Distance between two points on the earth.'''
    earth_radius = 6371.0009
    dLat = math.radians(lat2 - lat1)
    dLng = math.radians(lng2 - lng1)
    sindLat = math.sin(dLat / 2)
    sindLng = math.sin(dLng / 2)
    a = math.pow(sindLat, 2) + math.pow(sindLng, 2) * math.cos(math.radians(lat1)) * math.cos(math.radians(lat2))
    c = 2 * math.atan2(math.sqrt(a), math.sqrt(1-a))
    dist = earth_radius * c

    return dist


if __name__ == '__main__':
    print calculate_distance(0,0,0.5,0)
    print calculate_distance(0,0,0,0.5)
    print calculate_distance(70,0,70,0.5)
    print get_bin(45.46536, -73.66585)
    print get_bin(45.4719057, -73.6349034)