/// <summary>
/// Computes the ellipsoid.
/// </summary>
/// <returns>The ellipsoid.</returns>
/// <exception cref="System.IO.InvalidDataException">Prime meridian code is invalid.</exception>
private Ellipsoid ComputeEllipsoid()
{
Int32 code = Convert.ToInt32(_currentGeoKeys[GeoKey.GeodeticEllipsoid]);
// EPSG ellipsoid codes
if (code >= 8000 && code <= 8999)
{
return(Ellipsoids.FromIdentifier("EPSG::" + code).FirstOrDefault());
}
// user-defined ellipsoid
if (code == Int16.MaxValue)
{
Double semiMajorAxis = Convert.ToDouble(_currentGeoKeys[GeoKey.GeodeticSemiMajorAxis]);
// either semi-minor axis or the inverse flattening is defined
if (_currentGeoKeys.ContainsKey(GeoKey.GeodeticSemiMinorAxis))
{
Double semiMinorAxis = Convert.ToDouble(_currentGeoKeys[2058]);
return(Ellipsoid.FromSemiMinorAxis(Ellipsoid.UserDefinedIdentifier, Ellipsoid.UserDefinedName, semiMajorAxis, semiMinorAxis));
}
else
{
Double inverseFlattening = Convert.ToDouble(_currentGeoKeys[GeoKey.GeodeticInverseFlattening]);
return(Ellipsoid.FromInverseFlattening(Ellipsoid.UserDefinedIdentifier, Ellipsoid.UserDefinedName, semiMajorAxis, inverseFlattening));
}
}
throw new InvalidDataException("Prime meridian code is invalid.");
}
/// <summary>
/// 空间坐标转大地坐标
/// </summary>
/// <param name="X"></param>
/// <param name="Y"></param>
/// <param name="Z"></param>
/// <param name="ellipsoid"></param>
/// <returns></returns>
public static PointBLH TranslateXYZToBLH(double X, double Y, double Z, Ellipsoids ellipsoid)
{
Ellipsoid ellipsoidTemp = Ellipsoid.Instance(ellipsoid);
double ee = ellipsoidTemp.e * ellipsoidTemp.e;
double p = 180 / Math.PI;
double B, L, H;
L = Math.Atan(Y / X);
if (X < 0)
{
L += Math.PI;
}
double r = Math.Sqrt(X * X + Y * Y);
double B1 = Math.Atan(Z / r);
double B2;
while (true)
{
double W1 = Math.Sqrt(1 - ee * (Math.Sin(B1) * Math.Sin(B1)));
double N1 = ellipsoidTemp.a / W1;
B2 = Math.Atan((Z + N1 * ee * Math.Sin(B1)) / r);
if (Math.Abs(B2 - B1) <= 0.0000000001)
{
break;
}
B1 = B2;
}
B = B2;
double W = Math.Sqrt(1 - ee * (Math.Sin(B2) * Math.Sin(B2)));
double N = ellipsoidTemp.a / W;
H = r / Math.Cos(B2) - N;
return(new PointBLH(B * p, L * p, H));
}
/// <summary>
/// 大地坐标转空间坐标
/// </summary>
/// <param name="B"></param>
/// <param name="L"></param>
/// <param name="H"></param>
/// <param name="ellipsoid"></param>
/// <returns></returns>
public static Point3D TranslateBLHToXYZ(double B, double L, double H, Ellipsoids ellipsoid)
{
double p = 180 / Math.PI;
B = B / p;
L = L / p;
double x = 0, y = 0, z = 0;
Ellipsoid ellipsoidTemp = Ellipsoid.Instance(ellipsoid);
double ee = ellipsoidTemp.e * ellipsoidTemp.e;
double N = ellipsoidTemp.a / (Math.Sqrt(1 - (ee * Math.Sin(B) * Math.Sin(B))));
x = (N + H) * Math.Cos(B) * Math.Cos(L);
y = (N + H) * Math.Cos(B) * Math.Sin(L);
z = (N * (1 - ee) + H) * Math.Sin(B);
return(new Point3D(x, y, z));
}
/// <summary>
/// Инициализирует новый экземпляр класса <see cref="Ellipsoid"/>.
/// </summary>
/// <param name="ell"> Имя эллипсоида из коллекции доступных эллипсоидов. </param>
public Ellipsoid(Ellipsoids ell)
{
double[,] ellParams = new double[, ]
{
// Эллипсоид Красовского
{ 6378245.000, 298.3 },
// Эллипсоид WGS 84
{ 6378137.000, 298.257223563 },
// Эллипсоид ПЗ-90
{ 6378136.000, 298.25784 }
};
this.a = ellParams[(int)ell, 0];
this.f = 1 / ellParams[(int)ell, 1];
e1_2 = 1 - b * b / (a * a);
e2_2 = a * a / (b * b) - 1;
}
/// <summary>
/// 创建常用的标准椭球
/// </summary>
/// <param name="type"></param>
/// <returns></returns>
public static Ellipsoid Instance(Ellipsoids ellipsoidstype)
{
switch (ellipsoidstype)
{
case Ellipsoids.XiAn1980:
return(new Ellipsoid(6378140.0, 6356755.288157528));
case Ellipsoids.CGCS2000:
return(new Ellipsoid(6378137, 6356752.31414035615));
case Ellipsoids.BeiJing1954:
return(new Ellipsoid(6378245.0, 6356863.018773047));
case Ellipsoids.WGS1984:
return(new Ellipsoid(6378137, 6356752.3142451793));
default:
return(new Ellipsoid(6378137, 6356752.31414035615));
}
}
/// <summary>
/// 平面坐标转大地坐标，高斯反算(X值为横坐标，且不带带号)
/// </summary>
/// <param name="X">横坐标值（不带带号）</param>
/// <param name="Y">纵坐标</param>
/// <param name="ZoneWidth">带宽</param>
/// <param name="longitude0">中央经度</param>
/// <param name="ellipsoid">椭球</param>
/// <returns></returns>
public static PointBLH ProjectToBL(double X, double Y, double H, int ZoneWidth, double longitude0, Ellipsoids ellipsoid)
{
//对于有带号的坐标，去除带号(超过六位数，只取六位)
if (X > 10000000)
{
X = X - X / 1000000 * 1000000;
}
Ellipsoid ellipsoidTemp = Ellipsoid.Instance(ellipsoid); //椭球
double longitude1, latitude1, X0, Y0;
double p = 180.0 / Math.PI; //弧度常数
longitude0 = longitude0 / p; // 中央经线
//带内起算坐标
X0 = 500000;
Y0 = 0;
//带内坐标值
double xval = X - X0;
double yval = Y - Y0;
//相关参数
double e2 = 2 * ellipsoidTemp.f - ellipsoidTemp.f * ellipsoidTemp.f;
double e1 = (1.0 - Math.Sqrt(1 - e2)) / (1.0 + Math.Sqrt(1 - e2));
double ee = e2 / (1 - e2);
double M = yval;
double u = M / (ellipsoidTemp.a * (1 - e2 / 4 - 3 * e2 * e2 / 64 - 5 * e2 * e2 * e2 / 256));
double bf = u + (3 * e1 / 2 - 27 * e1 * e1 * e1 / 32) * Math.Sin(2 * u) + (21 * e1 * e1 / 16 - 55 * e1 * e1 * e1 * e1 / 32) * Math.Sin(4 * u) + (151 * e1 * e1 * e1 / 96) * Math.Sin(6 * u) + (1097 * e1 * e1 * e1 * e1 / 512) * Math.Sin(8 * u);
double C = ee * Math.Cos(bf) * Math.Cos(bf);
double T = Math.Tan(bf) * Math.Tan(bf);
double NN = ellipsoidTemp.a / Math.Sqrt(1.0 - e2 * Math.Sin(bf) * Math.Sin(bf));
double R = ellipsoidTemp.a * (1 - e2) / Math.Sqrt((1 - e2 * Math.Sin(bf) * Math.Sin(bf)) * (1 - e2 * Math.Sin(bf) * Math.Sin(bf)) * (1 - e2 * Math.Sin(bf) * Math.Sin(bf)));
double D = xval / NN;
// 计算经度(Longitude) 纬度(Latitude)
longitude1 = longitude0 + (D - (1 + 2 * T + C) * D * D * D / 6 + (5 - 2 * C + 28 * T - 3 * C * C + 8 * ee + 24 * T * T) * D * D * D * D * D / 120) / Math.Cos(bf);
latitude1 = bf - (NN * Math.Tan(bf) / R) * (D * D / 2 - (5 + 3 * T + 10 * C - 4 * C * C - 9 * ee) * D * D * D * D / 24 + (61 + 90 * T + 298 * C + 45 * T * T - 256 * ee - 3 * C * C) * D * D * D * D * D * D / 720);
// 弧度转换为度
double L = longitude1 * p;
double B = latitude1 * p;
return(new PointBLH(B, L, H));
}
/// <summary>
/// 大地坐标转平面坐标，高斯正算(输出X值为横坐标，且不带带号)
/// </summary>
/// <param name="B">纬度</param>
/// <param name="L">经度</param>
/// <param name="ZoneWidth">带宽</param>
/// <param name="longitude0">中央经度</param>
/// <returns></returns>
public static Point2D ProjectToXY(double B, double L, double H, int ZoneWidth, double longitude0, Ellipsoids ellipsoid)
{
Ellipsoid ellipsoidTemp = Ellipsoid.Instance(ellipsoid);//椭球
double longitude1, latitude1;
double p = 180.0 / Math.PI;
longitude0 = longitude0 / p;
// 转换为弧度
longitude1 = L / p;
latitude1 = B / p;
double e2 = 2 * ellipsoidTemp.f - ellipsoidTemp.f * ellipsoidTemp.f;
double ee = e2 * (1.0 - e2);
double NN = ellipsoidTemp.a / Math.Sqrt(1.0 - e2 * Math.Sin(latitude1) * Math.Sin(latitude1));
double T = Math.Tan(latitude1) * Math.Tan(latitude1);
double C = ee * Math.Cos(latitude1) * Math.Cos(latitude1);
double A = (longitude1 - longitude0) * Math.Cos(latitude1);
double M = ellipsoidTemp.a * ((1 - e2 / 4 - 3 * e2 * e2 / 64 - 5 * e2 * e2 * e2 / 256) * latitude1 - (3 * e2 / 8 + 3 * e2 * e2 / 32 + 45 * e2 * e2 * e2 / 1024) * Math.Sin(2 * latitude1) + (15 * e2 * e2 / 256 + 45 * e2 * e2 * e2 / 1024) * Math.Sin(4 * latitude1) - (35 * e2 * e2 * e2 / 3072) * Math.Sin(6 * latitude1));
//计算x y坐标值
double xval = NN * (A + (1 - T + C) * A * A * A / 6 + (5 - 18 * T + T * T + 72 * C - 58 * ee) * A * A * A * A * A / 120);
double yval = M + NN * Math.Tan(latitude1) * (A * A / 2 + (5 - T + 9 * C + 4 * C * C) * A * A * A * A / 24 + (61 - 58 * T + T * T + 600 * C - 330 * ee) * A * A * A * A * A * A / 720);
//起算坐标值
double X0 = 500000;
double Y0 = 0;
xval = xval + X0;
yval = yval + Y0;
return(new Point2D(xval, yval, H));
}
