[C#] UTM to DD and DD to UTM.

[Necuno]

Has one done this before?

Using this to check my calculations
http://www.latlong.net/lat-long-utm.html
http://www.uwgb.edu/dutchs/UsefulData/ConvertUTMNoOZ.HTM

Here's more information on the the conversion
http://www.uwgb.edu/dutchs/UsefulData/UTMFormulas.HTM
http://www.uwgb.edu/dutchs/FieldMethods/UTMSystem.htm

Most of the c# exmaples I could find are using doubles, but when I look at this one's javascript (http://www.uwgb.edu/dutchs/UsefulData/ConvertUTMNoOZ.HTM) and I go through Declarations() (line 9), at f = 1/DatumFlat[Item];//polar flattening.

	DatumEqRad = [[COLOR="#FF0000"]6378137.0[/COLOR],6378137.0,6378137.0,6378135.0,6378160.0,6378245.0,6378206.4,6378388.0,6378388.0,6378249.1,6378206.4,6377563.4,6377397.2,6377276.3];	
	DatumFlat = [[COLOR="#FF0000"]298.2572236[/COLOR], 298.2572236, 298.2572215,	298.2597208, 298.2497323, 298.2997381, 294.9786982,296.9993621, 296.9993621, 293.4660167, 294.9786982, 299.3247788, 299.1527052, 300.8021499]; 
	Item = 0;//Default
	k0 = 0.9996;//scale on central meridian
	a = DatumEqRad[Item];//equatorial radius, meters. 
[COLOR="#FF0000"]	f = 1/DatumFlat[Item];//polar flattening.[/COLOR]
	b = a*(1-f);//polar axis.
	e = Math.sqrt(1 - b*b/a*a);//eccentricity

It would be 1/298.2572236: (using WSG82, which is Item 0 of DatumFlat)

js: 0.0033528106643315514
double: 0.003352810664331551
decimal: 0.0033528106643315511638122819
calculator: 0.00335281066433155116381228192993

The thing is, the page's value at f (JS) is different from what I have at f (C#) which with a zone of 43, easting of 337183.35, northing of 218617.85 and South of Equator gives me: LON: 1.971278 / LAT: -73.536107 instead of LON: 37.857547 / LAT: -87.540331.

I know that the double thing is about precision and capacity, but js AFAIK is using a float number type? The short so far I could not get an example that actually gives same results as the two websites I use to double check it with....

Here's the rough code, I do a pologise, but it is a literal copy and paste from JS

Declarations:

      int item = 0;//WSG84
      double k0 = 0.9996;//scale on central meridian
      double a = DatumEqRad[item];//equatorial radius, meters. 
      double f = 1 / DatumFlat[item];//polar flattening.
      double b = a * (1 - f);//polar axis.
      double e = Math.Sqrt(1 - b * b / a * a);//eccentricity
      double drad = Math.PI / 180;//Convert degrees to radians)
      double latd = 0;//latitude in degrees
      double phi = 0;//latitude (north +, south -), but uses phi in reference
      double e0 = e / Math.Sqrt(1 - e * e);//e prime in reference
      double N = a / Math.Sqrt(1 - Math.Pow(e * Math.Sin(phi), 2));
      double T = Math.Pow(Math.Tan(phi), 2);
      double C = Math.Pow(e * Math.Cos(phi), 2);
      double lng = 0;//Longitude (e = +, w = -) - can't use long - reserved word
      double lng0 = 0;//longitude of central meridian
      double lngd = 0;//longitude in degrees
      double M = 0;//M requires calculation
      double x = 0;//x coordinate
      double y = 0;//y coordinate
      double k = 1;//local scale
      double utmz = 30;//utm zone
      double zcm = 0;//zone central meridian
      string DigraphLetrsE = "ABCDEFGHJKLMNPQRSTUVWXYZ";
      string DigraphLetrsN = "ABCDEFGHJKLMNPQRSTUV";
      //document.getElementById("EqRadBox").value = a;
      //document.getElementById("PolRadBox").value = b;
      //document.getElementById("FlatBox").value = f;
      //ocument.getElementById("RecipBox").value = 1 / f;
      bool OOZok = false;

UTMToDD

 //Convert UTM Coordinates to Geographic
      k0 = 0.9996;//scale on central meridian
      b = a * (1 - f);//polar axis.
      e = Math.Sqrt(1 - (b / a) * (b / a));//eccentricity
      e0 = e / Math.Sqrt(1 - e * e);//Called e prime in reference
      double esq = (1 - (b / a) * (b / a));//e squared for use in expansions
      double e0sq = e * e / (1 - e * e);// e0 squared - always even powers
      x = double.Parse(txtEasting.Text.Trim());// parseFloat(document.getElementById("UTMeBox1").value);

      //if (x<160000 || x>840000){alert("Outside permissible range of easting values \n Results may be unreliable \n Use with caution");} 
      y = double.Parse(txtNorthing.Text.Trim()); //parseFloat(document.getElementById("UTMnBox1").value);

      //alert(y)
      //if (y<0){alert("Negative values not allowed \n Results may be unreliable \n Use with caution");}
      //if (y>10000000){alert("Northing may not exceed 10,000,000 \n Results may be unreliable \n Use with caution");}

      utmz = int.Parse(txtZone.Text.Trim());// (t parseFloat(document.getElementById("UTMzBox1").value);
      zcm = 3 + 6 * (utmz - 1) - 180;//Central meridian of zone
      double e1 = (1 - Math.Sqrt(1 - e * e)) / (1 + Math.Sqrt(1 - e * e));//Called e1 in USGS PP 1395 also
      double M0 = 0;//In case origin other than zero lat - not needed for standard UTM
      M = M0 + y / k0;//Arc length along standard meridian. 

      if (chkSouth.Checked) { M = M0 + (y - 10000000) / k; }
      //if (document.getElementById("SHemBox").checked === true){M=M0+(y-10000000)/k;}

      double mu = M / (a * (1 - esq * (1 / 4 + esq * (3 / 64 + 5 * esq / 256))));
      double phi1 = mu + e1 * (3 / 2 - 27 * e1 * e1 / 32) * Math.Sin(2 * mu) + e1 * e1 * (21 / 16 - 55 * e1 * e1 / 32) * Math.Sin(4 * mu);//Footprint Latitude
      phi1 = phi1 + e1 * e1 * e1 * (Math.Sin(6 * mu) * 151 / 96 + e1 * Math.Sin(8 * mu) * 1097 / 512);
      double C1 = e0sq * Math.Pow(Math.Cos(phi1), 2);
      double T1 = Math.Pow(Math.Tan(phi1), 2);
      double N1 = a / Math.Sqrt(1 - Math.Pow(e * Math.Sin(phi1), 2));
      double R1 = N1 * (1 - e * e) / (1 - Math.Pow(e * Math.Sin(phi1), 2));
      double D = (x - 500000) / (N1 * k0);
      phi = (D * D) * (1 / 2 - D * D * (5 + 3 * T1 + 10 * C1 - 4 * C1 * C1 - 9 * e0sq) / 24);
      phi = phi + Math.Pow(D, 6) * (61 + 90 * T1 + 298 * C1 + 45 * T1 * T1 - 252 * e0sq - 3 * C1 * C1) / 720;
      phi = phi1 - (N1 * Math.Tan(phi1) / R1) * phi;

      //Output Latitude
      lblLatitude.Text = (Math.Floor(1000000 * phi / drad) / 1000000).ToString();
      //	document.getElementById("DDLatBox0").value = Math.Floor(1000000*phi/drad)/1000000;

      //Longitude
      lng = D * (1 + D * D * ((-1 - 2 * T1 - C1) / 6 + D * D * (5 - 2 * C1 + 28 * T1 - 3 * C1 * C1 + 8 * e0sq + 24 * T1 * T1) / 120)) / Math.Cos(phi1);
      lngd = zcm + lng / drad;

      //Output Longitude
      lbllongitude.Text = (Math.Floor(1000000 * lngd) / 1000000).ToString();
      //  document.getElementById("DDLonBox0").value = Math.Floor(1000000*lngd)/1000000;

:edit
Found something that seems to be working in this thread
http://forum.worldwindcentral.com/s...TM-here-it-is-!!&p=66142&viewfull=1#post66142