/// <summary>
/// Converts Geodetic coords to Geocentric cartesian.
/// </summary>
/// <param name="GeodeticLat">Geodetic lat in degrees.</param>
/// <param name="GeodeticLon">Geodetic lon in degrees.</param>
/// <param name="GeodeticHeight">Geodetic height in meters.</param>
/// <param name="GeocentricX">Geocentric x.</param>
/// <param name="GeocentricY">Geocentric y.</param>
/// <param name="GeocentricZ">Geocentric z.</param>
/// <param name="R">R.</param>
public static void GeodeticToGeocentric(double GeodeticLat, double GeodeticLon, double GeodeticHeight,
out double GeocentricX, out double GeocentricY, out double GeocentricZ,
RefEllipsoid R)
{
GeodeticLat = DegToRad(GeodeticLat);
GeodeticLon = DegToRad(GeodeticLon);
double MajorAxis, MinorAxis;
GetEllipsoidAxis(R, out MajorAxis, out MinorAxis);
double Esq = (Math.Pow(MajorAxis, 2) - Math.Pow(MinorAxis, 2)) / Math.Pow(MajorAxis, 2);
double V = MajorAxis / Math.Sqrt(1 - (Esq * Math.Pow(Math.Sin(GeodeticLat), 2)));
GeocentricX = (V + GeodeticHeight) * Math.Cos(GeodeticLat) * Math.Cos(GeodeticLon);
GeocentricY = (V + GeodeticHeight) * Math.Cos(GeodeticLat) * Math.Sin(GeodeticLon);
GeocentricZ = ((1 - Esq) * V + GeodeticHeight) * Math.Sin(GeodeticLat);
}
public static void GeocentricToGeodetic(double x, double y, double z,
out double lat, out double lon, out double alt, RefEllipsoid R)
{
double a, b, t;
GetEllipsoidAxis(R, out a, out b);
double e2 = 1.0 - (b * b) / (a * a); // 1st eccentricity sqrd
double ed2 = (a * a) / (b * b) - 1.0; // 2nd eccentricity sqrd
double a2 = a * a;
double b2 = b * b;
double z2 = z * z;
double e4 = e2 * e2;
double r2 = x * x + y * y;
double r = Math.Sqrt(r2);
double E2 = a2 - b2;
double F = 54.0 * b2 * z2;
double G = r2 + (1.0 - e2) * z2 - e2 * E2;
double C = e4 * F * r2 / (G * G * G);
double S = Math.Pow(1.0 + C + Math.Sqrt(C * C + 2.0 * C), 1.0 / 3.0);
t = S + 1.0 / S + 1.0;
double P = F / (3.0 * t * t * G * G);
double Q = Math.Sqrt(1.0 + 2.0 * e4 * P);
double r0 = -(P * e2 * r) / (1.0 + Q) + Math.Sqrt(0.5 * a2 * (1.0 + 1.0 / Q) - (P * (1 - e2) * z2) / (Q * (1.0 + Q)) - 0.5 * P * r2);
t = r - e2 * r0;
double U = Math.Sqrt(t * t + z2);
double V = Math.Sqrt(t * t + (1.0 - e2) * z2);
t = b2 / (a * V);
alt = U * (1.0 - t);
lat = Math.Atan2(z + ed2 * t * z, r);
lon = Math.Atan2(y, x);
// convert to degrees
lat = RadToDeg(lat);
lon = RadToDeg(lon);
}
public static void GetEllipsoidAxis(RefEllipsoid R, out double MajorAxis, out double MinorAxis)
{
switch (R)
{
case RefEllipsoid.Airy:
MajorAxis = 6377563.396;
MinorAxis = 6356256.909;
// 1/F 299.324965
break;
case RefEllipsoid.Airy_Modified:
MajorAxis = 6377340.189;
MinorAxis = 6356034.448;
// 1/F 299.324965
break;
case RefEllipsoid.Australian_National:
MajorAxis = 6378160.000;
MinorAxis = 6356774.719;
// 1/F 298.250000
break;
case RefEllipsoid.Bessel_1841:
MajorAxis = 6377397.155;
MinorAxis = 6356078.963;
// 1/F 299.152813
break;
case RefEllipsoid.Bessel_1841_Namibia:
MajorAxis = 6377483.865;
MinorAxis = 6356078.963;
// 1/F 299.152813
break;
case RefEllipsoid.Clarke_1866:
MajorAxis = 6378206.400;
MinorAxis = 6356583.800;
// 1/F 294.978698
break;
case RefEllipsoid.Clarke_1880:
MajorAxis = 6378249.145;
MinorAxis = 6356514.870;
// 1/F 293.465000
break;
case RefEllipsoid.Everest_Sabah_Sarawak:
MajorAxis = 6377298.556;
MinorAxis = 6356097.550;
// 1/F 300.801700
break;
case RefEllipsoid.Everest_1830:
MajorAxis = 6377276.345;
MinorAxis = 6356075.413;
// 1/F 300.801700
break;
case RefEllipsoid.Everest_1948:
MajorAxis = 6377304.063;
MinorAxis = 6356103.039;
// 1/F 300.801700
break;
case RefEllipsoid.Everest_1956:
MajorAxis = 6377301.243;
MinorAxis = 6356100.228;
// 1/F 300.801700
break;
case RefEllipsoid.Everest_1969:
MajorAxis = 6377295.664;
MinorAxis = 6356094.668;
// 1/F 300.801700
break;
case RefEllipsoid.Fischer_1960:
MajorAxis = 6378166.000;
MinorAxis = 6356784.284;
// 1/F 298.300000
break;
case RefEllipsoid.Fischer_1960_Modified:
MajorAxis = 6378155.000;
MinorAxis = 6356773.320;
// 1/F 298.300000
break;
case RefEllipsoid.Fischer_1968:
MajorAxis = 6378150.000;
MinorAxis = 6356768.337;
// 1/F 298.300000
break;
case RefEllipsoid.GRS_1980:
MajorAxis = 6378137.000;
MinorAxis = 6356752.314;
// 1/F 298.257222
break;
case RefEllipsoid.Helmert_1906:
MajorAxis = 6378200.000;
MinorAxis = 6356818.170;
// 1/F 298.300000
break;
case RefEllipsoid.Hough:
MajorAxis = 6378270.000;
MinorAxis = 6356794.343;
// 1/F 297.000000
break;
case RefEllipsoid.International_1924:
MajorAxis = 6378388.000;
MinorAxis = 6356911.946;
// 1/F 297.000000
break;
case RefEllipsoid.Karsovsky_1940:
MajorAxis = 6378245.000;
MinorAxis = 6356863.019;
// 1/F 298.300000
break;
case RefEllipsoid.SGS_1985:
MajorAxis = 6378136.000;
MinorAxis = 6356751.302;
// 1/F 298.257000
break;
case RefEllipsoid.South_American_1969:
MajorAxis = 6378160.000;
MinorAxis = 6356774.719;
// 1/F 298.250000
break;
case RefEllipsoid.Sphere_6371km:
MajorAxis = 6371000;
MinorAxis = 6371000;
break;
case RefEllipsoid.WGS_1960:
MajorAxis = 6378165.000;
MinorAxis = 6356783.287;
// 1/F 298.300000
break;
case RefEllipsoid.WGS_1966:
MajorAxis = 6378145.000;
MinorAxis = 6356759.769;
// 1/F 298.250000
break;
case RefEllipsoid.WGS_1972:
MajorAxis = 6378135.000;
MinorAxis = 6356750.520;
// 1/F 298.260000
break;
case RefEllipsoid.WGS_1984:
MajorAxis = 6378137.000;
MinorAxis = 6356752.314245;
// 1/F 298.257224
break;
default:
// TODO: evaluate, what default value should be assigned?
MajorAxis = 0;
MinorAxis = 0;
break;
}
}
