球体上任意两点之间的所有圆中，大圆距离最小，本程序就是计算球体上两点之间的大圆距离-All circle between any two points on a sphere, a great circle distance minimum, this procedure is to calculate the great circle distance between two points on a sphere

通过经纬度计算球体上两点距离，计算速度很快(Calculating the distance between two points on the sphere through latitude and longitude is very fast)