class GPSPosition
{
public double Latitude { get; set; }
public double Longitude { get; set; }
}
/// <summary>
/// http://www.oschina.net/code/snippet_260395_39205
/// </summary>
class GPSConverter
{
static readonly double PI = Math.PI;
static readonly double x_pi = Math.PI * 3000.0 / 180.0;
static readonly double a = 6378245.0; //卫星椭球坐标投影到平面地图坐标系的投影因子。
static readonly double ee = 0.00669342162296594323;//椭球的偏心率。
/// <summary>
/// 中国坐标偏移标准，Google Map、高德、腾讯使用 to 百度坐标偏移标准，Baidu Map使用
/// </summary>
/// <param name="lng"></param>
/// <param name="lat"></param>
/// <returns></returns>
public static GPSPosition GCJ02ToBD09(double lng, double lat)
{
double x = lng, y = lat;
var z = Math.Sqrt(x * x + y * y) + 0.00002 * Math.Sin(y * x_pi);
var theta = Math.Atan2(y, x) + 0.000003 * Math.Cos(x * x_pi);
var bdLon = z * Math.Cos(theta) + 0.0065;
var bdLat = z * Math.Sin(theta) + 0.006;
return new GPSPosition()
{
Latitude = bdLat,
Longitude = bdLon
};
}
/// <summary>
/// 中国坐标偏移标准，Google Map、高德、腾讯使用 to 国际标准，GPS坐标（Google Earth使用、或者GPS模块）
/// </summary>
/// <param name="lng"></param>
/// <param name="lat"></param>
/// <returns></returns>
public static GPSPosition GCJ02ToWGS84(double lng, double lat)
{
var initDelta = 0.01;
var threshold = 0.000000001;
double dLat = initDelta, dLon = initDelta;
double mLat = lat - dLat, mLon = lng - dLon;
double pLat = lat + dLat, pLon = lng + dLon;
double wgsLat, wgsLon, i = 0;
while (true)
{
wgsLat = (mLat + pLat) / 2;
wgsLon = (mLon + pLon) / 2;
var tmp = gcj_encrypt(wgsLat, wgsLon);
dLat = tmp.lat - lat;
dLon = tmp.lon - lng;
if ((Math.Abs(dLat) < threshold) && (Math.Abs(dLon) < threshold))
break;
if (dLat > 0) pLat = wgsLat; else mLat = wgsLat;
if (dLon > 0) pLon = wgsLon; else mLon = wgsLon;
if (++i > 10000) break;
}
//console.log(i);
return new GPSPosition()
{
Latitude = wgsLat,
Longitude = wgsLon
};
}
/// <summary>
/// 百度坐标偏移标准，Baidu Map使用 to 中国坐标偏移标准，Google Map、高德、腾讯使用
/// </summary>
/// <param name="bdLon"></param>
/// <param name="bdLat"></param>
/// <returns></returns>
public static GPSPosition BD09ToGCJ02(double bdLon, double bdLat)
{
double x = bdLon - 0.0065, y = bdLat - 0.006;
var z = Math.Sqrt(x * x + y * y) - 0.00002 * Math.Sin(y * x_pi);
var theta = Math.Atan2(y, x) - 0.000003 * Math.Cos(x * x_pi);
var gcjLon = z * Math.Cos(theta);
var gcjLat = z * Math.Sin(theta);
return new GPSPosition()
{
Latitude = gcjLat,
Longitude = gcjLon
};
}
/// <summary>
/// WGS84 转 GCJ02
/// </summary>
/// <param name="lat"></param>
/// <param name="lon"></param>
/// <returns></returns>
public static GPSPosition WGS84ToGCJ02(double lng, double lat)
{
double dLat = transformLat(lng - 105.0, lat - 35.0);
double dLon = transformLon(lng - 105.0, lat - 35.0);
double radLat = 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 = lat + dLat;
double mgLon = lng + dLon;
return new GPSPosition()
{
Latitude = mgLat,
Longitude = mgLon
};
}
/// <summary>
/// WGS84 转 BD09
/// </summary>
/// <param name="lng"></param>
/// <param name="lat"></param>
/// <returns></returns>
public static GPSPosition WGS84ToBD09(double lng, double lat)
{
var temp = WGS84ToGCJ02(lng, lat);
return GCJ02ToBD09(temp.Longitude, temp.Latitude);
}
static dynamic gcj_encrypt(double wgsLat, double wgsLon)
{
if (outOfChina(wgsLat, wgsLon))
return new { lat = wgsLat, lon = wgsLon };
var d = delta(wgsLat, wgsLon);
return new { lat = wgsLat + d.lat, lon = wgsLon + d.lon };
}
static dynamic 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 dynamic delta(double lat, double lon)
{
// Krasovsky 1940
//
// a = 6378245.0, 1/f = 298.3
// b = a * (1 - f)
// ee = (a^2 - b^2) / a^2;
var dLat = transformLat(lon - 105.0, lat - 35.0);
var dLon = transformLon(lon - 105.0, lat - 35.0);
var radLat = lat / 180.0 * PI;
var magic = Math.Sin(radLat);
magic = 1 - ee * magic * magic;
var sqrtMagic = Math.Sqrt(magic);
dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * PI);
dLon = (dLon * 180.0) / (a / sqrtMagic * Math.Cos(radLat) * PI);
return new { lat = dLat, lon = dLon };
}
static double transformLat(double x, double y)
{
var 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)
{
var 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;
}
}
