计算两点间距离

        privatestatic doubleGetDistance(double lng1, double lat1, doublelng2, double lat2)

        {

            varradLat1 = Rad(lat1);

            varradLat2 = Rad(lat2);

            vara = radLat1 - radLat2;

            varb = Rad(lng1) - Rad(lng2);

            vars = 2 * Math.Asin(Math.Sqrt(Math.Pow(Math.Sin(a/ 2), 2) + Math.Cos(radLat1) * Math.Cos(radLat2) * Math.Pow(Math.Sin(b / 2), 2)));

            s = s * 6378137.0;// 取WGS84标准参考椭球中的地球长半径(单位:m)

            s = Math.Round(s * 10000) / 10000;

            returns;

        }

 

        privatestatic doubleRad(double d)

        {

            returnd * Math.PI / 180.0;

        }