public static Utm FromWgs84(Wgs84 w)
{
Utm u = new Utm();
if (w == null) return u;
const double a = 6378137; //WGS84
const double eccSquared = 0.00669438; //WGS84
const double k0 = 0.9996;
//Make sure the longitude is between -180.00 .. 179.9
double LongTemp = (w.Longitude + 180) - ((int)((w.Longitude + 180) / 360)) * 360 - 180; // -180.00 .. 179.9;
double LatRad = w.Latitude * deg2rad;
double LongRad = LongTemp * deg2rad;
int ZoneNumber = ((int)((LongTemp + 180) / 6)) + 1;
if (w.Latitude >= 56.0 && w.Latitude < 64.0 && LongTemp >= 3.0 && LongTemp < 12.0)
ZoneNumber = 32;
// Special zones for Svalbard
if (w.Latitude >= 72.0 && w.Latitude < 84.0)
{
if (LongTemp >= 0.0 && LongTemp < 9.0) ZoneNumber = 31;
else if (LongTemp >= 9.0 && LongTemp < 21.0) ZoneNumber = 33;
else if (LongTemp >= 21.0 && LongTemp < 33.0) ZoneNumber = 35;
else if (LongTemp >= 33.0 && LongTemp < 42.0) ZoneNumber = 37;
}
double LongOrigin = (ZoneNumber - 1) * 6 - 180 + 3;
double LongOriginRad = LongOrigin * deg2rad;
//compute the UTM Zone from the latitude and longitude
u.Zone = ZoneNumber.ToString() + UTMLetterDesignator(w.Latitude);
const double eccPrimeSquared = (eccSquared) / (1 - eccSquared);
double N = a / Math.Sqrt(1 - eccSquared * Math.Sin(LatRad) * Math.Sin(LatRad));
double T = Math.Tan(LatRad) * Math.Tan(LatRad);
double C = eccPrimeSquared * Math.Cos(LatRad) * Math.Cos(LatRad);
double A = Math.Cos(LatRad) * (LongRad - LongOriginRad);
double M = a * ((1 - eccSquared / 4 - 3 * eccSquared * eccSquared / 64 - 5 * eccSquared * eccSquared * eccSquared / 256) * LatRad
- (3 * eccSquared / 8 + 3 * eccSquared * eccSquared / 32 + 45 * eccSquared * eccSquared * eccSquared / 1024) * Math.Sin(2 * LatRad)
+ (15 * eccSquared * eccSquared / 256 + 45 * eccSquared * eccSquared * eccSquared / 1024) * Math.Sin(4 * LatRad)
- (35 * eccSquared * eccSquared * eccSquared / 3072) * Math.Sin(6 * LatRad));
u.Easting = k0 * N * (A + (1 - T + C) * A * A * A / 6 + (5 - 18 * T + T * T + 72 * C - 58 * eccPrimeSquared)
* A * A * A * A * A / 120) + 500000.0;
u.Northing = k0 * (M + N * Math.Tan(LatRad) * (A * A / 2 + (5 - T + 9 * C + 4 * C * C) * A * A * A * A / 24
+ (61 - 58 * T + T * T + 600 * C - 330 * eccPrimeSquared) * A * A * A * A * A * A / 720));
if (w.Latitude < 0)
u.Northing += 10000000.0; //10000000 meter offset for southern hemisphere
return u;
}
public double DistanceTo(Wgs84 w)
{
double pk = 180.0 / Math.PI;
double a1 = w.Latitude / pk;
double a2 = w.Longitude / pk;
double b1 = Latitude / pk;
double b2 = Longitude / pk;
double t1 = Math.Cos(a1) * Math.Cos(a2) * Math.Cos(b1) * Math.Cos(b2);
double t2 = Math.Cos(a1) * Math.Sin(a2) * Math.Cos(b1) * Math.Sin(b2);
double t3 = Math.Sin(a1) * Math.Sin(b1);
double tt = Math.Acos(t1 + t2 + t3);
return 6366000 * tt;
}
public static Wgs84 FromUtm(Utm u)
{
bool isNorthHemisphere = u.Zone.Last() >= 'N';
var diflat = -0.00066286966871111111111111111111111111;
var diflon = -0.0003868060578;
var zone = int.Parse(u.Zone.Remove(u.Zone.Length - 1));
var c_sa = 6378137.000000;
var c_sb = 6356752.314245;
var e2 = Math.Pow((Math.Pow(c_sa, 2) - Math.Pow(c_sb, 2)), 0.5) / c_sb;
var e2cuadrada = Math.Pow(e2, 2);
var c = Math.Pow(c_sa, 2) / c_sb;
var x = u.Easting - 500000;
var y = isNorthHemisphere ? u.Northing : u.Northing - 10000000;
var s = ((zone * 6.0) - 183.0);
var lat = y / (c_sa * 0.9996);
var v = (c / Math.Pow(1 + (e2cuadrada * Math.Pow(Math.Cos(lat), 2)), 0.5)) * 0.9996;
var a = x / v;
var a1 = Math.Sin(2 * lat);
var a2 = a1 * Math.Pow((Math.Cos(lat)), 2);
var j2 = lat + (a1 / 2.0);
var j4 = ((3 * j2) + a2) / 4.0;
var j6 = ((5 * j4) + Math.Pow(a2 * (Math.Cos(lat)), 2)) / 3.0;
var alfa = (3.0 / 4.0) * e2cuadrada;
var beta = (5.0 / 3.0) * Math.Pow(alfa, 2);
var gama = (35.0 / 27.0) * Math.Pow(alfa, 3);
var bm = 0.9996 * c * (lat - alfa * j2 + beta * j4 - gama * j6);
var b = (y - bm) / v;
var epsi = ((e2cuadrada * Math.Pow(a, 2)) / 2.0) * Math.Pow((Math.Cos(lat)), 2);
var eps = a * (1 - (epsi / 3.0));
var nab = (b * (1 - epsi)) + lat;
var senoheps = (Math.Exp(eps) - Math.Exp(-eps)) / 2.0;
var delt = Math.Atan(senoheps / (Math.Cos(nab)));
var tao = Math.Atan(Math.Cos(delt) * Math.Tan(nab));
Wgs84 w_out = new Wgs84
{
Longitude = ((delt * (180.0 / Math.PI)) + s) + diflon,
Latitude = ((lat + (1 + e2cuadrada * Math.Pow(Math.Cos(lat), 2) - (3.0 / 2.0) * e2cuadrada * Math.Sin(lat) * Math.Cos(lat) * (tao - lat)) * (tao - lat)) * (180.0 / Math.PI)) + diflat
};
return w_out;
}
