protected LatLonCoordinates ToLatLon()
{
double k0 = 0.9996;
double a = Datum.a;
double e2 = Datum.e2;
double ep2 = (e2) / (1 - e2);
double e1 = (1 - Math.Sqrt(1 - e2)) / (1 + Math.Sqrt(1 - e2));
int nUTMZoneLen = UtmZone.Length;
char ZoneLetter = UtmZone[nUTMZoneLen - 1];
//int NorthernHemisphere; //1 for northern hemispher, 0 for southern
double x = Easting - 500000.0; //remove 500,000 meter offset for longitude
double y = Northing;
int ZoneNumber = Int16.Parse(UtmZone.Substring(0, nUTMZoneLen - 1));
if ((ZoneLetter - 'N') >= 0)
{
//point is in northern hemisphere
}
else
{
//point is in southern hemisphere
y -= 10000000.0;//remove 10,000,000 meter offset used for southern hemisphere
}
double LongOriginRad = ((ZoneNumber - 1) * 6 - 180 + 3) * Angle.DEG2RAD; //+3 puts origin in middle of zone
double N1, T1, C1, R1, D, M;
double mu, phi;
M = y / k0;
mu = M / (a * (1 - e2 / 4 - 3 * e2 * e2 / 64 - 5 * e2 * e2 * e2 / 256));
phi = mu + (3 * e1 / 2 - 27 * e1 * e1 * e1 / 32) * Math.Sin(2 * mu)
+ (21 * e1 * e1 / 16 - 55 * e1 * e1 * e1 * e1 / 32) * Math.Sin(4 * mu)
+ (151 * e1 * e1 * e1 / 96) * Math.Sin(6 * mu);
N1 = a / Math.Sqrt(1 - e2 * Math.Sin(phi) * Math.Sin(phi));
T1 = Math.Tan(phi) * Math.Tan(phi);
C1 = ep2 * Math.Cos(phi) * Math.Cos(phi);
R1 = a * (1 - e2) / Math.Pow(1 - e2 * Math.Sin(phi) * Math.Sin(phi), 1.5);
D = x / (N1 * k0);
var latitude = new Angle()
{
Radians =
(phi - (N1 * Math.Tan(phi) / R1) * (D * D / 2 - (5 + 3 * T1 + 10 * C1 - 4 * C1 * C1 - 9 * ep2) * D * D * D * D / 24
+ (61 + 90 * T1 + 298 * C1 + 45 * T1 * T1 - 252 * ep2 - 3 * C1 * C1) * D * D * D * D * D * D / 720))
};
var longitude = new Angle()
{
Radians =
LongOriginRad +
((D - (1 + 2 * T1 + C1) * D * D * D / 6 + (5 - 2 * C1 + 28 * T1 - 3 * C1 * C1 + 8 * ep2 + 24 * T1 * T1) * D * D * D * D * D / 120) / Math.Cos(phi))
};
return(new LatLonCoordinates(Datum, latitude, longitude, Altitude));
}
public override UtmCoordinates ToUtm(Datum targetDatum, int targetZoneNumber = 0)
{
UtmCoordinates utmc;
if (Datum == targetDatum && int.Parse(UtmZone.Substring(0, 2)) == targetZoneNumber)
{
//already in the target datum and zone
utmc = this;
}
else
{
//transform to latlon
var llc = ToLatLon();
//transform to UTM (another datum)
utmc = llc.ToUtm(targetDatum, targetZoneNumber);
}
return(utmc);
}
