private static ICoordinateTransformation Proj2Geog(IProjectedCoordinateSystem source, IGeographicCoordinateSystem target)
{
if (source.GeographicCoordinateSystem.EqualParams(target))
{
IMathTransform mathTransform = CreateCoordinateOperation(source.Projection, source.GeographicCoordinateSystem.HorizontalDatum.Ellipsoid, source.LinearUnit).Inverse();
return new CoordinateTransformation(source, target, TransformType.Transformation, mathTransform,
String.Empty, String.Empty, -1, String.Empty, String.Empty);
}
else
{ // Geographic coordinatesystems differ - Create concatenated transform
ConcatenatedTransform ct = new ConcatenatedTransform();
CoordinateTransformationFactory ctFac = new CoordinateTransformationFactory();
ct.CoordinateTransformationList.Add(ctFac.CreateFromCoordinateSystems(source, source.GeographicCoordinateSystem));
ct.CoordinateTransformationList.Add(ctFac.CreateFromCoordinateSystems(source.GeographicCoordinateSystem, target));
return new CoordinateTransformation(source,
target, TransformType.Transformation, ct,
String.Empty, String.Empty, -1, String.Empty, String.Empty);
}
}
/// <summary>
/// Creates geographic to geographic transformation.
/// </summary>
/// <remarks>Adds a datum shift if nessesary</remarks>
/// <param name="source">Source coordinate system</param>
/// <param name="target">TargetCoordinate system</param>
/// <returns>The requested transformation</returns>
private ICoordinateTransformation CreateGeog2Geog(IGeographicCoordinateSystem source, IGeographicCoordinateSystem target)
{
if (source.HorizontalDatum.EqualParams(target.HorizontalDatum))
{
//datum shift is not needed
return new CoordinateTransformation(source,
target, TransformType.Conversion, new GeographicTransform(source, target),
String.Empty, String.Empty, -1, String.Empty, String.Empty);
}
else
{
//datum shift
// transformation into a geocentric system, datum shift and return to the system of geographical
CoordinateTransformationFactory ctFac = new CoordinateTransformationFactory();
CoordinateSystemFactory cFac = new CoordinateSystemFactory();
IGeocentricCoordinateSystem sourceCentric = cFac.CreateGeocentricCoordinateSystem(source.HorizontalDatum.Name + " Geocentric",
source.HorizontalDatum, LinearUnit.Metre, source.PrimeMeridian);
IGeocentricCoordinateSystem targetCentric = cFac.CreateGeocentricCoordinateSystem(target.HorizontalDatum.Name + " Geocentric",
target.HorizontalDatum, LinearUnit.Metre, source.PrimeMeridian);
ConcatenatedTransform ct = new ConcatenatedTransform();
ct.CoordinateTransformationList.Add(ctFac.CreateFromCoordinateSystems(source, sourceCentric));
ct.CoordinateTransformationList.Add(ctFac.CreateFromCoordinateSystems(sourceCentric, targetCentric));
ct.CoordinateTransformationList.Add(ctFac.CreateFromCoordinateSystems(targetCentric, target));
return new CoordinateTransformation(source,
target, TransformType.Transformation, ct,
String.Empty, String.Empty, -1, String.Empty, String.Empty);
}
}
private static ICoordinateTransformation Proj2Proj(IProjectedCoordinateSystem source, IProjectedCoordinateSystem target)
{
ConcatenatedTransform ct = new ConcatenatedTransform();
CoordinateTransformationFactory ctFac = new CoordinateTransformationFactory();
//First transform from projection to geographic
ct.CoordinateTransformationList.Add(ctFac.CreateFromCoordinateSystems(source, source.GeographicCoordinateSystem));
//Transform geographic to geographic:
ct.CoordinateTransformationList.Add(ctFac.CreateFromCoordinateSystems(source.GeographicCoordinateSystem, target.GeographicCoordinateSystem));
//Transform to new projection
ct.CoordinateTransformationList.Add(ctFac.CreateFromCoordinateSystems(target.GeographicCoordinateSystem, target));
return new CoordinateTransformation(source,
target, TransformType.Transformation, ct,
String.Empty, String.Empty, -1, String.Empty, String.Empty);
}
