private static Int32 GridSize(Int16 digits)
{
Int16 actualDigits = UtmPoint.MakeDigitValid(digits);
Int32 result = Convert.ToInt32(Math.Pow(10, UtmPoint.MaximumDigits - actualDigits));
return(result);
}
private Boolean SameZone(UtmPoint point)
{
GeoPoint geoPoint = new GeoPoint(point, Datum);
UtmPoint realUtm = geoPoint.CalcUTM();
Boolean result = (CentralPoint.ZoneNumber == realUtm.ZoneNumber);
return(result);
}
private void SetMgrs(String value)
{
String mgrs = value.Replace(" ", "");
Int16 digits = Convert.ToInt16((mgrs.Length - 1) / 2);
CentralPoint = MakeCentral(UtmPoint.ParseMgrsString(value), digits);
_Digits = digits;
Name = value;
}
/// <summary>
/// Initializes a new instance of the GeoPoint class.
/// </summary>
/// <param name="utmPoint">UTM coordinates.</param>
/// <param name="datum">Geographical datum.</param>
public GeoPoint(UtmPoint utmPoint, GeoDatum datum)
{
Double excentricitySquared = datum.Ellipsoid.ExcentricitySquared;
Double equatorialRadius = datum.Ellipsoid.SemiMajorAxis;
Boolean northernHemisphere = utmPoint.IsNorthernHemisphere;
Int32 zoneNumber = utmPoint.ZoneNumber;
Double x = utmPoint.Easting - 500000.0; //remove 500,000 meter offset for longitude
Double y = utmPoint.Northing;
if (!northernHemisphere)
{
// point is in southern hemisphere
y = y - 10000000.0; // remove 10,000,000 meter offset used for southern hemisphere
}
Double longOrigin = (zoneNumber - 1) * 6 - 180 + 3; // +3 puts origin in middle of zone
Double excentricityPrimeSquared = (excentricitySquared) / (1 - excentricitySquared);
Double M = y / dScaleFactor;
Double mu = M / (equatorialRadius * (1 - excentricitySquared / 4 - 3 * excentricitySquared * excentricitySquared / 64 - 5 * excentricitySquared * excentricitySquared * excentricitySquared / 256));
Double e1 = (1 - Math.Sqrt(1 - excentricitySquared)) / (1 + Math.Sqrt(1 - excentricitySquared));
// phi in radians
Double phi1Rad = 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);
// convert to degrees
Double phi1 = phi1Rad * _convertRadianToDegree;
Double N1 = equatorialRadius / Math.Sqrt(1 - excentricitySquared * Math.Sin(phi1Rad) * Math.Sin(phi1Rad));
Double T1 = Math.Tan(phi1Rad) * Math.Tan(phi1Rad);
Double C1 = excentricityPrimeSquared * Math.Cos(phi1Rad) * Math.Cos(phi1Rad);
Double R1 = equatorialRadius * (1 - excentricitySquared) / Math.Pow(1 - excentricitySquared * Math.Sin(phi1Rad) * Math.Sin(phi1Rad), 1.5);
Double D = x / (N1 * dScaleFactor);
// phi in radians
Double latitude = phi1Rad - (N1 * Math.Tan(phi1Rad) / R1) * (D * D / 2 - (5 + 3 * T1 + 10 * C1 - 4 * C1 * C1 - 9 * excentricityPrimeSquared) * D * D * D * D / 24
+ (61 + 90 * T1 + 298 * C1 + 45 * T1 * T1 - 252 * excentricityPrimeSquared - 3 * C1 * C1) * D * D * D * D * D * D / 720);
// convert to degrees
latitude = latitude * _convertRadianToDegree;
// lon in radians
Double longitude = (D - (1 + 2 * T1 + C1) * D * D * D / 6 + (5 - 2 * C1 + 28 * T1 - 3 * C1 * C1 + 8 * excentricityPrimeSquared + 24 * T1 * T1)
* D * D * D * D * D / 120) / Math.Cos(phi1Rad);
// convert to degrees
longitude = longOrigin + longitude * _convertRadianToDegree;
Longitude = longitude;
Latitude = latitude;
_Datum = datum;
}
private static UtmPoint MakeCentral(UtmPoint point, Int16 digits)
{
String value = point.ToUtmString(digits);
UtmPoint utmPoint = new UtmPoint(value);
Double distance = 0.5 * GridSize(digits);
Double easting = utmPoint.Easting + distance;
Double northing = utmPoint.Northing + distance;
UtmPoint middlePoint = new UtmPoint(easting, northing, utmPoint.ZoneNumber, utmPoint.IsNorthernHemisphere);
return(middlePoint);
}
public UtmPoint NorthWestCornerUtm()
{
String value = CentralPoint.ToUtmString(_Digits);
UtmPoint result = new UtmPoint(value);
if (!SameZone(result))
{
result = LimitToZone(result);
}
return(result);
}
public UtmPoint SouthEastCornerUtm()
{
String value = CentralPoint.ToUtmString(_Digits);
UtmPoint result = new UtmPoint(value);
result.Easting += GridSize(_Digits);
result.Northing += GridSize(_Digits);
if (!SameZone(result))
{
result = LimitToZone(result);
}
return(result);
}
private UtmPoint LimitToZone(UtmPoint point)
{
UtmPoint result = new UtmPoint(point);
Int32 minEasting = 0;
Int32 maxEasting = 0;
if (point.Easting < CentralPoint.Easting)
{
minEasting = point.Easting;
maxEasting = minEasting + GridSize(_Digits);
}
else
{
maxEasting = point.Easting;
minEasting = maxEasting - GridSize(_Digits);
}
Int32 leftZone = 0;
{
UtmPoint tempUtmPoint = new UtmPoint(point);
tempUtmPoint.Easting = minEasting;
GeoPoint tempGeoPoint = new GeoPoint(tempUtmPoint, Datum);
tempUtmPoint = tempGeoPoint.CalcUTM();
leftZone = tempUtmPoint.ZoneNumber;
}
Int32 eastingDiff = maxEasting - minEasting;
while (eastingDiff > 1)
{
Int32 tempEasting = minEasting + eastingDiff / 2;
result = new UtmPoint(point);
result.Easting = tempEasting;
GeoPoint tempGeoPoint = new GeoPoint(result, Datum);
UtmPoint empUtmPoint = tempGeoPoint.CalcUTM();
if (empUtmPoint.ZoneNumber > leftZone)
{
maxEasting = tempEasting;
}
else
{
minEasting = tempEasting;
}
eastingDiff = eastingDiff / 2;
}
return(result);
}
public UtmPoint ActualCentralPoint()
{
String value = CentralPoint.ToUtmString(_Digits);
UtmPoint west = new UtmPoint(value);
west.Northing += GridSize(_Digits) / 2;
UtmPoint east = new UtmPoint(west);
east.Easting += GridSize(_Digits);
if (!SameZone(west))
{
west = LimitToZone(west);
}
if (!SameZone(east))
{
east = LimitToZone(east);
}
UtmPoint result = new UtmPoint(value);
result.Northing += GridSize(_Digits) / 2;
result.Easting = (west.Easting + east.Easting) / 2;
return(result);
}
public UtmPoint CalcUTM()
{
//converts lat/long to UTM coords. Equations from USGS Bulletin 1532
//East Longitudes are positive, West longitudes are negative.
//North latitudes are positive, South latitudes are negative
//Lat and Long are in decimal degrees
double eccSquared = _Datum.Ellipsoid.ExcentricitySquared;
double dEquatorialRadius = _Datum.Ellipsoid.SemiMajorAxis;
double k0 = 0.9996;
double LongOrigin;
double eccPrimeSquared = (eccSquared) / (1 - eccSquared);
//Make sure the longitude is between -180.00 .. 179.9
double lLongitude = (Longitude + 180) - Math.Truncate((Longitude + 180) / 360) * 360 - 180; // -180.00 .. 179.9;
double LatRad = Latitude / _convertRadianToDegree;
double LongRad = Longitude / _convertRadianToDegree;
Int32 ZoneNumber = (Int32)Math.Truncate((lLongitude + 180) / 6) + 1;
if (Latitude >= 56.0 && Latitude < 64.0 && lLongitude >= 3.0 && lLongitude < 12.0)
{
ZoneNumber = 32; // larger zone for southern Norway
}
if (Latitude >= 72.0 && Latitude < 84.0)
{
// Special zones for Svalbard
if (lLongitude >= 0.0 && lLongitude < 9.0)
{
ZoneNumber = 31;
}
else if (lLongitude >= 9.0 && lLongitude < 21.0)
{
ZoneNumber = 33;
}
else if (lLongitude >= 21.0 && lLongitude < 33.0)
{
ZoneNumber = 35;
}
else if (lLongitude >= 33.0 && lLongitude < 42.0)
{
ZoneNumber = 37;
}
}
LongOrigin = (ZoneNumber - 1) * 6 - 180 + 3; //+3 puts origin in middle of zone
double LongOriginRad = LongOrigin / _convertRadianToDegree;
double N = dEquatorialRadius / 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 = dEquatorialRadius * ((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));
double UTMEasting = (double)(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);
double UTMNorthing = (double)(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 (Latitude < 0)
{
UTMNorthing += 10000000.0; //10000000 meter offset for southern hemisphere
}
UtmPoint lResult = new UtmPoint(
(Int32)Math.Truncate(UTMEasting),
(Int32)Math.Truncate(UTMNorthing),
ZoneNumber, Latitude >= 0);
return(lResult);
}
