plotweather.py 文件源码

def haversine(self, lat1, lon1, lat2, lon2):
        """
        Calculate the great circle distance between two points
        on the earth (specified in decimal degrees)
        """
   #     convert decimal degrees to radians
        lon1, lat1, lon2, lat2 = map(radians, [lon1, lat1, lon2, lat2])

   #     haversine formula
        dlon = lon2 - lon1
        dlat = lat2 - lat1
        a = sin(dlat / 2)**2 + cos(lat1) * cos(lat2) * sin(dlon / 2)**2
        c = 2 * asin(sqrt(a))

   #     6367 km is the radius of the Earth
        km = 6367 * c
        return km