经纬度之间距离计算

 

  /// <summary>
        /// 经纬度之间距离
        /// </summary>
        /// <param name="lng1">经度，通常大于90的</param>
        /// <param name="lat1">纬度，通常小于90的</param>
        /// <param name="lng2"></param>
        /// <param name="lat2"></param>
        /// <param name="gs">可以选默认的：WGS84</param>
        /// <returns></returns>
        public static double DistanceOfTwoPoints(double lng1, double lat1, double lng2, double lat2, GaussSphere gs)
        {
            double radLat1 = Rad(lat1);
            double radLat2 = Rad(lat2);
            double a = radLat1 - radLat2;
            double b = Rad(lng1) - Rad(lng2);
            double s = 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 * (gs == GaussSphere.WGS84 ? 6378137.0 : (gs == GaussSphere.Xian80 ? 6378140.0 : 6378245.0));
            s = Math.Round(s * 10000) / 10000;
            return s;
        }



        private static double Rad(double d)
        {
            return d * Math.PI / 180.0;
        }

        //GaussSphere 为自定义枚举类型
        /// <summary>
        /// 高斯投影中所选用的参考椭球
        /// </summary>
        public enum GaussSphere
        {
            Beijing54,
            Xian80,
            WGS84,
        }