坐标转换C#(Gcj02、wgs84、bd09互转)

using System;
using System.Collections.Generic;
using System.Text;

namespace GMap.NET.Util
{
public static class ConvertGPS
{
private static double pi = 3.1415926535897932384626;
private static double a = 6378245.0;
private static double ee = 0.00669342162296594323;
private static double bd_pi = 3.14159265358979324 * 3000.0 / 180.0;

    static Boolean outOfChina(double lat, double lon)
    {
        if (lon < 72.004 || lon > 137.8347)
            return true;
        if (lat < 0.8293 || lat > 55.8271)
            return true;
        return false;
    }

    static 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;
    }

    static double transformLon(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;
    }

    /** 
    * 84 to 火星坐标系 (GCJ-02) World Geodetic System ==> Mars Geodetic System 
    *  
    * @param lat 
    * @param lon 
    * @return 
    */

    public static PointLatLng gps84_To_Gcj02(PointLatLng Gpoint)
    {
        if (outOfChina(Gpoint.Lat, Gpoint.Lng))
        {
            return new PointLatLng(0, 0);
        }
        double dLat = transformLat(Gpoint.Lng - 105.0, Gpoint.Lat - 35.0);
        double dLon = transformLon(Gpoint.Lng - 105.0, Gpoint.Lat - 35.0);
        double radLat = Gpoint.Lat / 180.0 * pi;
        double magic = Math.Sin(radLat);
        magic = 1 - ee * magic * magic;
        double sqrtMagic = Math.Sqrt(magic);
        dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
        dLon = (dLon * 180.0) / (a / sqrtMagic * Math.Cos(radLat) * pi);
        double mgLat = Gpoint.Lat + dLat;
        double mgLon = Gpoint.Lng + dLon;
        return new PointLatLng(mgLat, mgLon);
    }
    static PointLatLng transform(PointLatLng Gpoint)
    {
        if (outOfChina(Gpoint.Lat, Gpoint.Lng))
        {
            return new PointLatLng(Gpoint.Lat, Gpoint.Lng);
        }
        double dLat = transformLat(Gpoint.Lng - 105.0, Gpoint.Lat - 35.0);
        double dLon = transformLon(Gpoint.Lng - 105.0, Gpoint.Lat - 35.0);
        double radLat = Gpoint.Lat / 180.0 * pi;
        double magic = Math.Sin(radLat);
        magic = 1 - ee * magic * magic;
        double sqrtMagic = Math.Sqrt(magic);
        dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
        dLon = (dLon * 180.0) / (a / sqrtMagic * Math.Cos(radLat) * pi);
        double mgLat = Gpoint.Lat + dLat;
        double mgLon = Gpoint.Lng + dLon;
        return new PointLatLng(mgLat, mgLon);
    }

    /** 
     * * 火星坐标系 (GCJ-02) to 84 * * @param lon * @param lat * @return 
     * */
    public static PointLatLng gcj02_To_Gps84(PointLatLng Gpoint)
    {
        PointLatLng gps = transform(Gpoint);
        double lontitude = Gpoint.Lng * 2 - gps.Lng;
        double latitude = Gpoint.Lat * 2 - gps.Lat;
        return new PointLatLng(latitude, lontitude);
    }
    /** 
     * 火星坐标系 (GCJ-02) 与百度坐标系 (BD-09) 的转换算法 将 GCJ-02 坐标转换成 BD-09 坐标 
     *  
     * @param gg_lat 
     * @param gg_lon 
     */
    public static PointLatLng gcj02_To_Bd09(PointLatLng Gpoint)
    {
        double x = Gpoint.Lng, y = Gpoint.Lat;
        double z = Math.Sqrt(x * x + y * y) + 0.00002 * Math.Sin(y * bd_pi);
        double theta = Math.Atan2(y, x) + 0.000003 * Math.Cos(x * bd_pi);
        double bd_lon = z * Math.Cos(theta) + 0.0065;
        double bd_lat = z * Math.Sin(theta) + 0.006;
        return new PointLatLng(bd_lat, bd_lon);
    }

    /** 
    * * 火星坐标系 (GCJ-02) 与百度坐标系 (BD-09) 的转换算法 * * 将 BD-09 坐标转换成GCJ-02 坐标 * * @param 
    * bd_lat * @param bd_lon * @return 
    */
    public static PointLatLng bd09_To_Gcj02(PointLatLng bdPoint)
    {
        double x = bdPoint.Lng - 0.0065, y = bdPoint.Lat - 0.006;
        double z = Math.Sqrt(x * x + y * y) - 0.00002 * Math.Sin(y * bd_pi);
        double theta = Math.Atan2(y, x) - 0.000003 * Math.Cos(x * bd_pi);
        double gg_lon = z * Math.Cos(theta);
        double gg_lat = z * Math.Sin(theta);
        return new PointLatLng(gg_lat, gg_lon);
    }

    /** 
     * (BD-09)-->84 
     * @param bd_lat 
     * @param bd_lon 
     * @return 
     */
    public static PointLatLng bd09_To_Gps84(PointLatLng bdPoint)
    {

        PointLatLng gcj02 = bd09_To_Gcj02(bdPoint);
        PointLatLng map84 = gcj02_To_Gps84(gcj02);
        return map84;

    }
    /** 
     * 84-->(BD-09)
     * @param bd_lat 
     * @param bd_lon 
     * @return 
     */
    public static PointLatLng Gps84_To_bd09(PointLatLng gpsPoint)
    {
        PointLatLng gcj02 = gps84_To_Gcj02(gpsPoint);
        PointLatLng bd09 = gcj02_To_Bd09(gcj02);
        return bd09;

    }

}

}