c#坐标系转换
坐标系介绍
| 坐标系 | 说明 | 产品 |
|---|---|---|
| WGS84 | 地球坐标系，国际通用坐标系，是最基础的坐标系。 | GPS 谷歌地图 高德地图（境外） |
| GCJ02 | 国家测量局02号标准，俗称火星坐标系，是在WGS84坐标系的基础上经过加密而来。国测局规定，国内出版的各种地图系统（包括电子形式），必须至少采用 GCJ-02 对地理位置进行首次加密的坐标系。 | 腾讯地图 高德地图（境内） |
| BD09 | 百度坐标系，是百度在GCJ02的基础上的二次加密的坐标系。 | 百度地图 |
| 其它 | 类似百度地图，在GCJ02的基础上使用加密算法进行二次加密的坐标系。 | 搜狗地图 |
Show The Code
public class GeoHelper
{
//地球半径，单位米
private const double EARTH_RADIUS = 6378137;
/// <summary>
/// 圆周率 较 Math.PI 精度更大
/// </summary>
private const double PI = 3.1415926535897932384626;
private const double X_PI = PI * 3000.0 / 180.0;
/// <summary>
/// 地理位置是否位于中国以外
/// </summary>
/// <param name="wgLat">WGS-84坐标纬度</param>
/// <param name="wgLng">WGS-84坐标经度</param>
/// <returns>
/// true：国外
/// false：国内
/// </returns>
public static bool OutOfChina(double wgLat, double wgLng)
{
if (wgLng < 72.004 || wgLng > 137.8347)
{
return true;
}
if (wgLat < 0.8293 || wgLat > 55.8271)
{
return true;
}
return false;
}
/// <summary>
/// WGS-84坐标系转火星坐标系 (GCJ-02)
/// </summary>
/// <param name="wgLat">WGS-84坐标纬度</param>
/// <param name="wgLng">WGS-84坐标经度</param>
/// <param name="mgLat">输出：GCJ-02坐标纬度</param>
/// <param name="mgLng">输出：GCJ-02坐标经度</param>
public static void WGS84ToGCJ02(double wgLat, double wgLng, out double mgLat, out double mgLng)
{
if (OutOfChina(wgLat, wgLng))
{
mgLat = wgLat;
mgLng = wgLng;
}
else
{
Delta(wgLat, wgLng, out double dLat, out double dLon);
mgLat = wgLat + dLat;
mgLng = wgLng + dLon;
}
}
/// <summary>
/// 火星坐标系 (GCJ-02)转WGS-84坐标系
/// </summary>
/// <param name="mgLat">GCJ-02坐标纬度</param>
/// <param name="mgLng">GCJ-02坐标经度</param>
/// <param name="wgLat">输出：WGS-84坐标纬度</param>
/// <param name="wgLng">输出：WGS-84坐标经度</param>
public static void GCJ02ToWGS84(double mgLat, double mgLng, out double wgLat, out double wgLng)
{
if (OutOfChina(mgLat, mgLng))
{
wgLat = mgLat;
wgLng = mgLng;
}
else
{
double dLat;
double dLon;
Delta(mgLat, mgLng, out dLat, out dLon);
wgLat = mgLat - dLat;
wgLng = mgLng - dLon;
}
}
/// <summary>
/// 火星坐标系 (GCJ-02)转WGS-84坐标系(精度更高)
/// </summary>
/// <param name="mgLat">GCJ-02坐标纬度</param>
/// <param name="mgLng">GCJ-02坐标经度</param>
/// <param name="wgLat">输出：WGS-84坐标纬度</param>
/// <param name="wgLon">输出：WGS-84坐标经度</param>
public static void GCJ02ToWGS84Exact(double mgLat, double mgLng, out double wgLat, out double wgLon)
{
const double InitDelta = 0.01;
// 精度 小数越多 精度越高
const double Threshold = 0.000001;
double dLat = InitDelta;
double dLon = InitDelta;
double mLat = mgLat - dLat;
double mLon = mgLng - dLon;
double pLat = mgLat + dLat;
double pLon = mgLng + dLon;
double nLat;
double nLon;
int i = 0;
do
{
wgLat = (mLat + pLat) / 2;
wgLon = (mLon + pLon) / 2;
WGS84ToGCJ02(wgLat, wgLon, out nLat, out nLon);
dLat = nLat - mgLat;
dLon = nLon - mgLng;
if ((Math.Abs(dLat) < Threshold) && (Math.Abs(dLon) < Threshold)) break;
if (dLat > 0) pLat = wgLat; else mLat = wgLat;
if (dLon > 0) pLon = wgLon; else mLon = wgLon;
} while (++i <= 30);
}
/// <summary>
/// 百度坐标系 (BD-09)转火星坐标系 (GCJ-02)
/// </summary>
/// <param name="bdLat">百度坐标系纬度</param>
/// <param name="bdLon">百度坐标系经度</param>
/// <param name="mgLat">输出：GCJ-02坐标纬度</param>
/// <param name="mgLon">输出：GCJ-02坐标经度</param>
public static void BD09ToGCJ02(double bdLat, double bdLon, out double mgLat, out double mgLon)
{
double x = bdLon - 0.0065;
double y = bdLat - 0.006;
double z = Math.Sqrt(x * x + y * y) - 0.00002 * Math.Sin(y * X_PI);
double theta = Math.Atan2(y, x) - 0.000003 * Math.Cos(x * X_PI);
mgLat = z * Math.Sin(theta);
mgLon = z * Math.Cos(theta);
}
/// <summary>
/// 火星坐标系 (GCJ-02)转百度坐标系 (BD-09)
/// </summary>
/// <param name="mgLat">GCJ-02坐标纬度</param>
/// <param name="mgLon">GCJ-02坐标经度</param>
/// <param name="bdLat">输出：百度坐标系纬度</param>
/// <param name="bdLon">输出：百度坐标系经度</param>
public static void GCJ02ToBD09(double mgLat, double mgLon, out double bdLat, out double bdLon)
{
double x = mgLon;
double y = mgLat;
double z = Math.Sqrt(x * x + y * y) + 0.00002 * Math.Sin(y * X_PI);
double theta = Math.Atan2(y, x) + 0.000003 * Math.Cos(x * X_PI);
bdLat = z * Math.Sin(theta) + 0.006;
bdLon = z * Math.Cos(theta) + 0.0065;
}
/// <summary>
/// WGS-84坐标系转百度坐标系 (BD-09)
/// </summary>
/// <param name="wgLat">WGS-84坐标纬度</param>
/// <param name="wgLon">WGS-84坐标经度</param>
/// <param name="bdLat">输出：百度坐标系纬度</param>
/// <param name="bdLon">输出：百度坐标系经度</param>
public static void WGS84ToBD09(double wgLat, double wgLon, out double bdLat, out double bdLon)
{
double mgLat;
double mgLon;
WGS84ToGCJ02(wgLat, wgLon, out mgLat, out mgLon);
GCJ02ToBD09(mgLat, mgLon, out bdLat, out bdLon);
}
/// <summary>
/// 百度坐标系 (BD-09)转WGS-84坐标系
/// </summary>
/// <param name="bdLat">百度坐标系纬度</param>
/// <param name="bdLon">百度坐标系经度</param>
/// <param name="wgLat">输出：WGS-84坐标纬度</param>
/// <param name="wgLon">输出：WGS-84坐标经度</param>
public static void BD09ToWGS84(double bdLat, double bdLon, out double wgLat, out double wgLon)
{
double mgLat;
double mgLon;
BD09ToGCJ02(bdLat, bdLon, out mgLat, out mgLon);
GCJ02ToWGS84(mgLat, mgLon, out wgLat, out wgLon);
}
public static double Distance(double LatA, double LonA, double LatB, double LonB)
{
const double EarthR = 6371000.0;
double x = Math.Cos(LatA * PI / 180.0) * Math.Cos(LatB * PI / 180.0) * Math.Cos((LonA - LonB) * PI / 180);
double y = Math.Sin(LatA * PI / 180.0) * Math.Sin(LatB * PI / 180.0);
double s = x + y;
if (s > 1) s = 1;
if (s < -1) s = -1;
return Math.Acos(s) * EarthR;
}
private static void Delta(double Lat, double Lon, out double dLat, out double dLon)
{
const double AXIS = 6378245.0;
const double EE = 0.00669342162296594323;
dLat = TransformLat(Lon - 105.0, Lat - 35.0);
dLon = TransformLon(Lon - 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) / ((AXIS * (1 - EE)) / (magic * sqrtMagic) * PI);
dLon = (dLon * 180.0) / (AXIS / sqrtMagic * Math.Cos(radLat) * PI);
}
private 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;
}
private 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;
}
}
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