private void ParseDatum(IDictionary <String, String> parameters, DatumParameters datumParam)
{
String towgs84;
if (parameters.TryGetValue(Proj4Keyword.towgs84, out towgs84))
{
double[] datumConvparameters = ParseToWGS84(towgs84);
datumParam.SetDatumTransform(datumConvparameters);
}
String code;
if (parameters.TryGetValue(Proj4Keyword.datum, out code))
{
Datum.Datum datum = registry.GetDatum(code);
if (datum == null)
{
throw new ArgumentException("Unknown datum: " + code);
}
datumParam.Datum = datum;
}
string grids;
if (parameters.TryGetValue(Proj4Keyword.nadgrids, out grids))
{
datumParam.SetNadGrids(grids);
}
}
public CoordinateReferenceSystem Parse(String name, String[] args)
{
if (args == null)
{
return(null);
}
IDictionary <String, String> parameters = CreateParameterMap(args);
Proj4Keyword.CheckUnsupported(parameters.Keys);
DatumParameters datumParam = new DatumParameters();
ParseDatum(parameters, datumParam);
ParseEllipsoid(parameters, datumParam);
Datum.Datum datum = datumParam.Datum;
Ellipsoid ellipsoid = datum.Ellipsoid;
// TODO: this makes a difference - why?
// which is better?
// Ellipsoid ellipsoid = datumParam.getEllipsoid();
Projection.Projection proj = ParseProjection(parameters, ellipsoid);
return(new CoordinateReferenceSystem(name, args, datum, proj));
}
/**
* Parse ellipsoid modifiers.
*
* @param parameters
* @param datumParam
*/
private static void ParseEllipsoidModifiers(IDictionary <String, String> parameters, DatumParameters datumParam)
{
/**
* Modifiers are mutually exclusive, so when one is detected method returns
*/
if (parameters.ContainsKey(Proj4Keyword.R_A))
{
datumParam.setR_A();
return;
}
}
private void ParseEllipsoid(IDictionary <String, String> parameters, DatumParameters datumParam)
{
double b = 0;
String s;
/*
* // not supported by PROJ4 s = (String) parameters.TryGetValue(Proj4Param.R); if (s !=
* null) a = Double.parseDouble(s);
*/
String code;
if (parameters.TryGetValue(Proj4Keyword.ellps, out code))
{
Ellipsoid ellipsoid = registry.GetEllipsoid(code);
if (ellipsoid == null)
{
throw new ArgumentException("Unknown ellipsoid: " + code);
}
datumParam.Ellipsoid = ellipsoid;
}
/*
* Explicit parameters override ellps and datum settings
*/
if (parameters.TryGetValue(Proj4Keyword.a, out s))
{
double a = Double.Parse(s, CultureInfo.InvariantCulture);
datumParam.EquatorRadius = a;
}
if (parameters.TryGetValue(Proj4Keyword.es, out s))
{
double es = Double.Parse(s, CultureInfo.InvariantCulture);
datumParam.EccentricitySquared = es;
}
if (parameters.TryGetValue(Proj4Keyword.rf, out s))
{
double rf = Double.Parse(s, CultureInfo.InvariantCulture);
datumParam.SetRF(rf);
}
if (parameters.TryGetValue(Proj4Keyword.f, out s))
{
double f = Double.Parse(s, CultureInfo.InvariantCulture);
datumParam.SetF(f);
}
if (parameters.TryGetValue(Proj4Keyword.b, out s))
{
b = Double.Parse(s, CultureInfo.InvariantCulture);
datumParam.SetB(b);
}
if (b == 0)
{
b = datumParam.EquatorRadius * Math.Sqrt(1.0 - datumParam.EccentricitySquared);
}
ParseEllipsoidModifiers(parameters, datumParam);
/*
* // None of these appear to be supported by PROJ4 ??
*
* s = (String)
* parameters.TryGetValue(Proj4Param.R_A); if (s != null && Boolean.getBoolean(s)) { a *=
* 1. - es * (SIXTH + es * (RA4 + es * RA6)); } else { s = (String)
* parameters.TryGetValue(Proj4Param.R_V); if (s != null && Boolean.getBoolean(s)) { a *=
* 1. - es * (SIXTH + es * (RV4 + es * RV6)); } else { s = (String)
* parameters.TryGetValue(Proj4Param.R_a); if (s != null && Boolean.getBoolean(s)) { a =
* .5 * (a + b); } else { s = (String) parameters.TryGetValue(Proj4Param.R_g); if (s !=
* null && Boolean.getBoolean(s)) { a = Math.sqrt(a * b); } else { s =
* (String) parameters.TryGetValue(Proj4Param.R_h); if (s != null &&
* Boolean.getBoolean(s)) { a = 2. * a * b / (a + b); es = 0.; } else { s =
* (String) parameters.TryGetValue(Proj4Param.R_lat_a); if (s != null) { double tmp =
* Math.sin(ParseAngle(s)); if (Math.abs(tmp) > MapMath.HALFPI) throw new
* ProjectionException("-11"); tmp = 1. - es * tmp * tmp; a *= .5 * (1. - es +
* tmp) / (tmp * Math.sqrt(tmp)); es = 0.; } else { s = (String)
* parameters.TryGetValue(Proj4Param.R_lat_g); if (s != null) { double tmp =
* Math.sin(ParseAngle(s)); if (Math.abs(tmp) > MapMath.HALFPI) throw new
* ProjectionException("-11"); tmp = 1. - es * tmp * tmp; a *= Math.sqrt(1. -
* es) / tmp; es = 0.; } } } } } } } }
*/
}