bonus.py 文件源码

def great_circle_dist(p1, p2):
    """Return the distance (in km) between two points in
    geographical coordinates.
    """
    lon0, lat0 = p1
    lon1, lat1 = p2
    EARTH_R = 6372.8
    lat0 = np.radians(float(lat0))
    lon0 = np.radians(float(lon0))
    lat1 = np.radians(float(lat1))
    lon1 = np.radians(float(lon1))
    dlon = lon0 - lon1
    y = np.sqrt(
        (np.cos(lat1) * np.sin(dlon)) ** 2
        + (np.cos(lat0) * np.sin(lat1)
           - np.sin(lat0) * np.cos(lat1) * np.cos(dlon)) ** 2)
    x = np.sin(lat0) * np.sin(lat1) + \
        np.cos(lat0) * np.cos(lat1) * np.cos(dlon)
    c = np.arctan2(y, x)
    return EARTH_R * c