This function computes the geodesic surface distance between two cordinates on the surface of the earth to an accuracy of about 50 meters 这个函数计算地面上两个不同坐标之间的测地线距离，精度达到50米。
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Compute geodesic distance between earth - this function computes the geodesic surface distance between two cordinates on the surface of the earth to an accuracy of about 50 meters 这个函数计算地面上两个不同坐标之间的测地线距离，精度达到50米。
