distance_functions.py 文件源码

def spherical_distance(a, b):
    lat1 = a[1]
    lon1 = a[0]
    lat2 = b[1]
    lon2 = b[0]
    R = 6371000.0
    rlon1 = lon1 * math.pi / 180.0
    rlon2 = lon2 * math.pi / 180.0
    rlat1 = lat1 * math.pi / 180.0
    rlat2 = lat2 * math.pi / 180.0
    dlon = (rlon1 - rlon2) / 2.0
    dlat = (rlat1 - rlat2) / 2.0
    lat12 = (rlat1 + rlat2) / 2.0
    sindlat = math.sin(dlat)
    sindlon = math.sin(dlon)
    cosdlon = math.cos(dlon)
    coslat12 = math.cos(lat12)
    f = sindlat * sindlat * cosdlon * cosdlon + sindlon * sindlon * coslat12 * coslat12
    f = math.sqrt(f)
    f = math.asin(f) * 2.0 # the angle between the points
    f *= R
    return f