/// <summary>
/// Creates a new instance of GeocentricGeodetic
/// </summary>
public GeocentricGeodetic(Spheroid gi)
{
_a = gi.EquatorialRadius;
_b = gi.PolarRadius;
_a2 = _a * _a;
_b2 = _b * _b;
_e2 = (_a2 - _b2) / _a2;
_ep2 = (_a2 - _b2) / _b2;
}
private static void DatumTransform(ProjectionInfo source, ProjectionInfo dest, double[][] points, int startIndex, int numPoints)
{
Spheroid wgs84 = new Spheroid(Proj4Ellipsoids.WGS_1984);
Datum sDatum = source.GeographicInfo.Datum;
Datum dDatum = dest.GeographicInfo.Datum;
double[][] zPoints = new double[points.Length][];
bool zIsTemp = false;
/* -------------------------------------------------------------------- */
/* We cannot do any meaningful datum transformation if either */
/* the source or destination are of an unknown datum type */
/* (ie. only a +ellps declaration, no +datum). This is new */
/* behavior for PROJ 4.6.0. */
/* -------------------------------------------------------------------- */
if (sDatum.DatumType == DatumTypes.Unknown ||
dDatum.DatumType == DatumTypes.Unknown)
{
return;
}
/* -------------------------------------------------------------------- */
/* Short cut if the datums are identical. */
/* -------------------------------------------------------------------- */
if (sDatum.Matches(dDatum))
{
return;
}
double srcA = sDatum.Spheroid.EquatorialRadius;
double srcEs = sDatum.Spheroid.EccentricitySquared();
double dstA = dDatum.Spheroid.EquatorialRadius;
double dstEs = dDatum.Spheroid.EccentricitySquared();
/* -------------------------------------------------------------------- */
/* Create a temporary Z value if one is not provided. */
/* -------------------------------------------------------------------- */
if (points[0].Length > 2)
{
zPoints = points;
}
else
{
for (int i = startIndex; i < numPoints; i++)
{
zPoints[i] = new[] { points[i][0], points[i][1], 0 };
}
zIsTemp = true;
}
/* -------------------------------------------------------------------- */
/* If this datum requires grid shifts, then apply it to geodetic */
/* coordinates. */
/* -------------------------------------------------------------------- */
if (sDatum.DatumType == DatumTypes.GridShift)
{
// pj_apply_gridshift( pj_param(srcdefn->params,"snadgrids").s, 0,
// point_count, point_offset, x, y, z );
GridShift.Apply(source.GeographicInfo.Datum.NadGrids, false, points, startIndex, numPoints);
srcA = wgs84.EquatorialRadius;
srcEs = wgs84.EccentricitySquared();
}
if (dDatum.DatumType == DatumTypes.GridShift)
{
dstA = wgs84.EquatorialRadius;
dstEs = wgs84.EccentricitySquared();
}
/* ==================================================================== */
/* Do we need to go through geocentric coordinates? */
/* ==================================================================== */
if (srcEs != dstEs || srcA != dstA ||
sDatum.DatumType == DatumTypes.Param3 ||
sDatum.DatumType == DatumTypes.Param7 ||
dDatum.DatumType == DatumTypes.Param3 ||
dDatum.DatumType == DatumTypes.Param7)
{
/* -------------------------------------------------------------------- */
/* Convert to geocentric coordinates. */
/* -------------------------------------------------------------------- */
GeocentricGeodetic gc = new GeocentricGeodetic(sDatum.Spheroid);
gc.GeodeticToGeocentric(zPoints, startIndex, numPoints);
/* -------------------------------------------------------------------- */
/* Convert between datums. */
/* -------------------------------------------------------------------- */
if (sDatum.DatumType == DatumTypes.Param3 || sDatum.DatumType == DatumTypes.Param7)
{
// pj_geocentric_to_wgs84( srcdefn, point_count, point_offset,x,y,z);
}
if (dDatum.DatumType == DatumTypes.Param3 || dDatum.DatumType == DatumTypes.Param7)
{
// pj_geocentric_from_wgs84( dstdefn, point_count,point_offset,x,y,z);
}
/* -------------------------------------------------------------------- */
/* Convert back to geodetic coordinates. */
/* -------------------------------------------------------------------- */
gc = new GeocentricGeodetic(dDatum.Spheroid);
gc.GeodeticToGeocentric(zPoints, startIndex, numPoints);
}
/* -------------------------------------------------------------------- */
/* Apply grid shift to destination if required. */
/* -------------------------------------------------------------------- */
if (dDatum.DatumType == DatumTypes.GridShift)
{
// pj_apply_gridshift( pj_param(dstdefn->params,"snadgrids").s, 1,
// point_count, point_offset, x, y, z );
GridShift.Apply(dest.GeographicInfo.Datum.NadGrids, true, points, startIndex, numPoints);
}
if (zIsTemp)
{
for (int i = startIndex; i < numPoints; i++)
{
points[i][0] = zPoints[i][0];
points[i][1] = zPoints[i][1];
}
}
}
/// <summary>
/// Uses a Proj4Datums enumeration in order to specify a known datum to
/// define the spheroid and to WGS calculation method and parameters
/// </summary>
/// <param name="standardDatum">The Proj4Datums enumeration specifying the known datum</param>
public Datum(Proj4Datums standardDatum)
{
_spheroid = new Spheroid();
AssignStandardDatum(standardDatum.ToString());
}
/// <summary>
/// uses a string name of a standard datum to create a new instance of the Datum class
/// </summary>
/// <param name="standardDatum">The string name of the datum to use</param>
public Datum(string standardDatum)
{
_spheroid = new Spheroid();
AssignStandardDatum(standardDatum);
}
/// <summary>
/// Creates a new instance of Datum
/// </summary>
public Datum()
{
_spheroid = new Spheroid();
}
/// <summary>
/// Reads the proj4 parameters and parses out the ones that control the
/// datum.
/// </summary>
/// <param name="parameters"></param>
/// <remarks>Originally ported from pj_datum_set.c</remarks>
public void ReadProj4Params(Dictionary <string, string> parameters)
{
DatumType = DatumTypes.Unknown;
/* -------------------------------------------------------------------- */
/* Is there a datum definition in the parameters list? If so, */
/* add the defining values to the parameter list. Notice that */
/* this will append the ellipse definition as well as the */
/* towgs84= and related parameters. It should also be pointed */
/* out that the addition is permanent rather than temporary */
/* like most other keyword expansion so that the ellipse */
/* definition will last into the pj_ell_set() function called */
/* after this one. */
/* -------------------------------------------------------------------- */
if (parameters.ContainsKey("datum"))
{
AssignStandardDatum(parameters["datum"]);
// Even though th ellipsoid is set by its known definition, we permit overriding it with a specifically defined ellps parameter
}
// ELLIPSOID PARAMETER
if (parameters.ContainsKey("ellps"))
{
Spheroid = new Spheroid(parameters["ellps"]);
}
else
{
if (parameters.ContainsKey("a"))
{
Spheroid.EquatorialRadius = double.Parse(parameters["a"]);
}
if (parameters.ContainsKey("b"))
{
Spheroid.PolarRadius = double.Parse(parameters["b"]);
}
if (parameters.ContainsKey("rf"))
{
Spheroid.SetInverseFlattening(double.Parse(parameters["rf"]));
}
if (parameters.ContainsKey("R"))
{
Spheroid.EquatorialRadius = double.Parse(parameters["R"]);
}
}
// DATUM PARAMETER
if (parameters.ContainsKey("nadgrids"))
{
_nadGrids = parameters["nadgrids"].Split(',');
_datumtype = DatumTypes.GridShift;
}
else if (parameters.ContainsKey("towgs84"))
{
string[] rawVals = parameters["towgs84"].Split(',');
_toWGS84 = new double[rawVals.Length];
for (int i = 0; i < rawVals.Length; i++)
{
_toWGS84[i] = double.Parse(rawVals[i]);
}
_datumtype = DatumTypes.Param7;
if (_toWGS84.Length < 7)
{
_datumtype = DatumTypes.Param3;
}
if (_toWGS84[3] == 0.0 && _toWGS84[4] == 0.0 &&
_toWGS84[5] == 0.0 && _toWGS84[6] == 0.0)
{
_datumtype = DatumTypes.Param3;
}
if (_datumtype == DatumTypes.Param7)
{
// Trnasform from arc seconds to radians
_toWGS84[3] *= SecToRad;
_toWGS84[4] *= SecToRad;
_toWGS84[5] *= SecToRad;
// transform from parts per millon to scaling factor
_toWGS84[6] = (_toWGS84[6] / 1000000.0) + 1;
}
}
}
private void AssignStandardDatum(string datumName)
{
string id = datumName.ToLower();
switch (id)
{
case "wgs84":
_toWGS84 = new double[] { 0, 0, 0 };
_spheroid = new Spheroid(Proj4Ellipsoids.WGS_1984);
_description = "WGS 1984";
_datumtype = DatumTypes.WGS84;
_name = "D_WGS_1984";
break;
case "ggrs87":
_toWGS84 = new[] { -199.87, 74.79, 246.62 };
_spheroid = new Spheroid(Proj4Ellipsoids.GRS_1980);
_description = "Greek Geodetic Reference System 1987";
_datumtype = DatumTypes.Param3;
break;
case "nad83":
_toWGS84 = new double[] { 0, 0, 0 };
_spheroid = new Spheroid(Proj4Ellipsoids.GRS_1980);
_description = "North American Datum 1983";
_datumtype = DatumTypes.WGS84;
break;
case "nad27":
_nadGrids = new[] { "@conus", "@alaska", "@ntv2_0.gsb", "@ntv1_can.dat" };
_spheroid = new Spheroid(Proj4Ellipsoids.Clarke_1866);
_description = "North American Datum 1927";
_datumtype = DatumTypes.GridShift;
break;
case "potsdam":
_toWGS84 = new[] { 606.0, 23.0, 413.0 };
_spheroid = new Spheroid(Proj4Ellipsoids.Bessel_1841);
_description = "Potsdam Rauenberg 1950 DHDN";
_datumtype = DatumTypes.Param3;
break;
case "carthage":
_toWGS84 = new[] { -263.0, 6, 413 };
_spheroid = new Spheroid(Proj4Ellipsoids.ClarkeModified_1880);
_description = "Carthage 1934 Tunisia";
_datumtype = DatumTypes.Param3;
break;
case "hermannskogel":
_toWGS84 = new[] { 653.0, -212.0, 449 };
_spheroid = new Spheroid(Proj4Ellipsoids.Bessel_1841);
_description = "Hermannskogel";
_datumtype = DatumTypes.Param3;
break;
case "ire65":
_toWGS84 = new[] { 482.530, -130.569, 564.557, -1.042, -.214, -.631, 8.15 };
_spheroid = new Spheroid(Proj4Ellipsoids.AiryModified);
_description = "Ireland 1965";
_datumtype = DatumTypes.Param7;
break;
case "nzgd49":
_toWGS84 = new[] { 59.47, -5.04, 187.44, 0.47, -0.1, 1.024, -4.5993 };
_spheroid = new Spheroid(Proj4Ellipsoids.International_1909);
_description = "New Zealand";
_datumtype = DatumTypes.Param7;
break;
case "osgb36":
_toWGS84 = new[] { 446.448, -125.157, 542.060, 0.1502, 0.2470, 0.8421, -20.4894 };
_spheroid = new Spheroid(Proj4Ellipsoids.Airy_1830);
_description = "Airy 1830";
_datumtype = DatumTypes.Param7;
break;
}
}
/// <summary>
/// Creates an esri well known text string for the datum part of the string
/// </summary>
/// <returns>The datum portion of the esri well known text</returns>
public string ToEsriString()
{
return(@"DATUM[""" + _name + @"""," + Spheroid.ToEsriString() + "]");
}
