在WGS84坐标系下，计算两点（经纬度坐标）之间的距离（单位：km）。

import math

def LLs2Dist(lat1, lon1, lat2, lon2):
    R = 6371
    dLat = (lat2 - lat1) * math.pi / 180.0
    dLon = (lon2 - lon1) * math.pi / 180.0

    a = math.sin(dLat / 2) * math.sin(dLat/2) + math.cos(lat1 * math.pi / 180.0) * math.cos(lat2 * math.pi / 180.0) * math.sin(dLon/2) * math.sin(dLon/2)
    c = 2 * math.atan2(math.sqrt(a), math.sqrt(1-a))
    dist = R * c
    return dist

验证：

x1 = 37.779388
y1 = -122.423246
x2 = 32.719464
y2 = -117.220406

dist = LLs2Dist(y1, x1, y2, x2)
print dist

输出结果为：

642.185478152