Instead of assuming the Earth to be a perfect sphere, this function takes into account the actual polar flattening of the earth and the equatorial bulge, which gives a much more accurate computation between the given coordinates.

• 它没有假设地球是一个完整的球面，而是考虑了地球的极轴扁平率和赤道鼓起率，这样就给出了两个坐标间更精确的距离。