public class TempGps

    {

        public double Tlng;

        public double Tlat;

    }

    public class GPS

    {

        public string oLng;//经度 度分秒坐标

        public string oLat;//纬度 度分秒坐标

        public double lng;//经度 WGS-84

        public double lat;//纬度 WGS-84

        public double gLng;//经度 GCJ-02 中国坐标偏移标准 Google Map、高德、腾讯使用

        public double gLat;//纬度 GCJ-02 中国坐标偏移标准 Google Map、高德、腾讯使用

        public double bLng;//经度 BD-09 百度坐标偏移标准，Baidu Map使用

        public double bLat;//纬度 BD-09 百度坐标偏移标准，Baidu Map使用

        public double PI = Math.PI;

        double xPI = Math.PI * 3000.0 / 180.0;

        public TempGps delta(TempGps t)

        {

            var a = 6378245.0; //  a: 卫星椭球坐标投影到平面地图坐标系的投影因子。

            var ee = 0.00669342162296594323; //  ee: 椭球的偏心率。

            var dLat = this.transformLat(t.Tlng - 105.0, t.Tlat - 35.0);

            var dLng = this.transformLng(t.Tlng - 105.0, t.Tlat - 35.0);

            var radLat = t.Tlat / 180.0 * PI;

            var magic = Math.Sin(radLat);

            magic = 1 - ee * magic * magic;

            var sqrtMagic = Math.Sqrt(magic);

            return new TempGps() { Tlat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * PI),  Tlng= (dLng * 180.0) / (a / sqrtMagic * Math.Cos(radLat) * PI) };

        }

        //WGS-84 to GCJ-02

        public void gcj_encrypt()

        {

            if (this.outOfChina(lng, lat))

            {

                gLng = lng;

                gLat = lat;

            }

            var t = this.delta(new TempGps() { Tlng = lng, Tlat = lat });

            gLng = t.Tlng+lng;

            gLat = t.Tlat+lat;

        }

        //GCJ-02 to WGS-84

        public void gcj_decrypt()

        {

            if (this.outOfChina(gLng, gLat))

            {

                lng = gLng;

                lat = gLat;

            }

            var t = this.delta(new TempGps() { Tlng = gLng, Tlat = gLat });

            lng = gLng-t.Tlng;

            lat = gLat-t.Tlat;

        }

        //GCJ-02 to BD-09

        public void bd_encrypt()

        {

            double x = gLng;

            double y = gLat;

            double z = Math.Sqrt(x * x + y * y) + 0.00002 * Math.Sin(y * xPI);

            double theta = Math.Atan2(y, x) + 0.000003 * Math.Cos(x * xPI);

            bLng = z * Math.Cos(theta) + 0.0065;

            bLat = z * Math.Sin(theta) + 0.006;

        }

        //BD-09 to GCJ-02

        public void bd_decrypt()

        {

            double x = bLng - 0.0065;

            double y = bLat - 0.006;

            double z = Math.Sqrt(x * x + y * y) + 0.00002 * Math.Sin(y * xPI);

            double theta = Math.Atan2(y, x) - 0.000003 * Math.Cos(x * xPI);

            gLng = z * Math.Cos(theta);

            gLat = z * Math.Sin(theta);

        }

        //WGS-84 to 度分秒坐标

        public void wgs_decrypt()

        {

            oLng = TranDegreeToDMs(lng);

            oLat = TranDegreeToDMs(lat);

        }

        //度分秒坐标 to WGS-84

        public void wgs_encrypt()

        {

            lng = TranDMsToDegree(oLng);

            lat = TranDMsToDegree(oLat);

        }

        public double TranDMsToDegree(string _dms)

        {

            string[] dms = _dms.Split('.');

            if (dms.Length > 2)

                return double.Parse(dms[0]) + double.Parse(dms[1]) / 60 + double.Parse(dms[2] + "." + dms[3] ?? "0") / 3600;

            else

                return 0d;

        }

        private static string TranDegreeToDMs(double d)

        {

            int Degree = Convert.ToInt16(Math.Truncate(d));//度

            d = d - Degree;

            int M = Convert.ToInt16(Math.Truncate((d) * 60));//分

            int S = Convert.ToInt16(Math.Round((d * 60 - M) * 60));

            if (S == 60)

            {

                M = M + 1;

                S = 0;

            }

            if (M == 60)

            {

                M = 0;

                Degree = Degree + 1;

            }

            string rstr = Degree.ToString() + ".";

            if (M < 10)

                rstr = rstr + "0" + M.ToString();

            else

                rstr = rstr + M.ToString();

            if (S < 10)

                rstr = rstr + "0" + S.ToString();

            else

                rstr = rstr + S.ToString();

            return rstr;

        }

        private bool outOfChina(double _lng, double _lat)

        {

            if (lng < 72.004 || lng > 137.8347)

                return true;

            if (lat < 0.8293 || lat > 55.8271)

                return true;

            return false;

        }

        private double transformLat(double x, double y)

        {

            double ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.Sqrt(Math.Abs(x));

            ret += (20.0 * Math.Sin(6.0 * x * PI) + 20.0 * Math.Sin(2.0 * x * PI)) * 2.0 / 3.0;

            ret += (20.0 * Math.Sin(y * PI) + 40.0 * Math.Sin(y / 3.0 * PI)) * 2.0 / 3.0;

            ret += (160.0 * Math.Sin(y / 12.0 * PI) + 320 * Math.Sin(y * PI / 30.0)) * 2.0 / 3.0;

            return ret;

        }

        private double transformLng(double x, double y)

        {

            double ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.Sqrt(Math.Abs(x));

            ret += (20.0 * Math.Sin(6.0 * x * PI) + 20.0 * Math.Sin(2.0 * x * PI)) * 2.0 / 3.0;

            ret += (20.0 * Math.Sin(x * PI) + 40.0 * Math.Sin(x / 3.0 * PI)) * 2.0 / 3.0;

            ret += (150.0 * Math.Sin(x / 12.0 * PI) + 300.0 * Math.Sin(x / 30.0 * PI)) * 2.0 / 3.0;

            return ret;

        }

    }

  GPS t = new GPS();

                    t.oLng = dt.Rows[i][1].ToString();

                    t.oLat = dt.Rows[i][2].ToString();

                    t.wgs_encrypt();

                    t.gcj_encrypt();

                    t.bd_encrypt();

                    cells[i+1, 3].PutValue(t.bLng);

                    cells[i+1, 4].PutValue(t.bLat);