/// <summary>
/// Geographic to geographic transformation
/// </summary>
/// <remarks>Adds a datum shift if nessesary</remarks>
/// <param name="source"></param>
/// <param name="target"></param>
/// <returns></returns>
private ICoordinateTransformation CreateGeog2Geog(IGeographicCoordinateSystem source, IGeographicCoordinateSystem target)
{
if (source.HorizontalDatum.EqualParams(target.HorizontalDatum))
{
//No datum shift needed
return(new CoordinateTransformation(source,
target, TransformType.Conversion, new GeographicTransform(source, target),
String.Empty, String.Empty, -1, String.Empty, String.Empty));
}
else
{
//Create datum shift
//Convert to geocentric, perform shift and return to geographic
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));
}
/// <summary>
/// Geocentric to Geocentric transformation
/// </summary>
/// <param name="source"></param>
/// <param name="target"></param>
/// <returns></returns>
private static ICoordinateTransformation CreateGeoc2Geoc(IGeocentricCoordinateSystem source, IGeocentricCoordinateSystem target)
{
ConcatenatedTransform ct = new ConcatenatedTransform();
//Does source has a datum different from WGS84 and is there a shift specified?
if (source.HorizontalDatum.Wgs84Parameters != null && !source.HorizontalDatum.Wgs84Parameters.HasZeroValuesOnly)
{
ct.CoordinateTransformationList.Add(
new CoordinateTransformation(
((target.HorizontalDatum.Wgs84Parameters == null || target.HorizontalDatum.Wgs84Parameters.HasZeroValuesOnly) ? target : GeocentricCoordinateSystem.WGS84),
source, TransformType.Transformation,
new DatumTransform(source.HorizontalDatum.Wgs84Parameters)
, "", "", -1, "", ""));
}
//Does target has a datum different from WGS84 and is there a shift specified?
if (target.HorizontalDatum.Wgs84Parameters != null && !target.HorizontalDatum.Wgs84Parameters.HasZeroValuesOnly)
{
ct.CoordinateTransformationList.Add(
new CoordinateTransformation(
((source.HorizontalDatum.Wgs84Parameters == null || source.HorizontalDatum.Wgs84Parameters.HasZeroValuesOnly) ? source : GeocentricCoordinateSystem.WGS84),
target,
TransformType.Transformation,
new DatumTransform(target.HorizontalDatum.Wgs84Parameters).Inverse()
, "", "", -1, "", ""));
}
if (ct.CoordinateTransformationList.Count == 1) //Since we only have one shift, lets just return the datumshift from/to wgs84
{
return(new CoordinateTransformation(source, target, TransformType.ConversionAndTransformation, ct.CoordinateTransformationList[0].MathTransform, "", "", -1, "", ""));
}
else
{
return(new CoordinateTransformation(source, target, TransformType.ConversionAndTransformation, ct, "", "", -1, "", ""));
}
}