/// <summary>
/// Reads and parses a WKT-formatted projection string.
/// </summary>
/// <param name="wkt">String containing WKT.</param>
/// <returns>Object representation of the WKT.</returns>
/// <exception cref="System.ArgumentException">If a token is not recognised.</exception>
public static IInfo Parse(string wkt)
{
IInfo returnObject = null;
StringReader reader = new StringReader(wkt);
WktStreamTokenizer tokenizer = new WktStreamTokenizer(reader);
tokenizer.NextToken();
string objectName = tokenizer.GetStringValue();
switch (objectName)
{
case "UNIT":
returnObject = ReadUnit(tokenizer);
break;
//case "VERT_DATUM":
// IVerticalDatum verticalDatum = ReadVerticalDatum(tokenizer);
// returnObject = verticalDatum;
// break;
case "SPHEROID":
returnObject = ReadEllipsoid(tokenizer);
break;
case "DATUM":
returnObject = ReadHorizontalDatum(tokenizer);;
break;
case "PRIMEM":
returnObject = ReadPrimeMeridian(tokenizer);
break;
case "VERT_CS":
case "GEOGCS":
case "PROJCS":
case "COMPD_CS":
case "GEOCCS":
case "FITTED_CS":
case "LOCAL_CS":
returnObject = ReadCoordinateSystem(wkt, tokenizer);
break;
default:
throw new ArgumentException(String.Format("'{0'} is not recongnized.", objectName));
}
reader.Close();
return(returnObject);
}
/// <summary>
/// Returns a <see cref="AngularUnit"/> given a piece of WKT.
/// </summary>
/// <param name="tokenizer">WktStreamTokenizer that has the WKT.</param>
/// <returns>An object that implements the IUnit interface.</returns>
private static IAngularUnit ReadAngularUnit(WktStreamTokenizer tokenizer)
{
tokenizer.ReadToken("[");
string unitName = tokenizer.ReadDoubleQuotedWord();
tokenizer.ReadToken(",");
tokenizer.NextToken();
double unitsPerUnit = tokenizer.GetNumericValue();
string authority = String.Empty;
long authorityCode = -1;
tokenizer.NextToken();
if (tokenizer.GetStringValue() == ",")
{
tokenizer.ReadAuthority(ref authority, ref authorityCode);
tokenizer.ReadToken("]");
}
return(new AngularUnit(unitsPerUnit, unitName, authority, authorityCode, String.Empty, String.Empty, String.Empty));
}
/// <summary>
///
/// </summary>
/// <param name="tokenizer"></param>
/// <returns></returns>
private static IPrimeMeridian ReadPrimeMeridian(WktStreamTokenizer tokenizer)
{
//PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]]
tokenizer.ReadToken("[");
string name = tokenizer.ReadDoubleQuotedWord();
tokenizer.ReadToken(",");
tokenizer.NextToken();
double longitude = tokenizer.GetNumericValue();
tokenizer.NextToken();
string authority = String.Empty;
long authorityCode = -1;
if (tokenizer.GetStringValue() == ",")
{
tokenizer.ReadAuthority(ref authority, ref authorityCode);
tokenizer.ReadToken("]");
}
// make an assumption about the Angular units - degrees.
IPrimeMeridian primeMeridian = new PrimeMeridian(longitude, AngularUnit.Degrees, name, authority, authorityCode, String.Empty, String.Empty, String.Empty);
return(primeMeridian);
}
/// <summary>
///
/// </summary>
/// <param name="tokenizer"></param>
/// <returns></returns>
private static IProjectedCoordinateSystem ReadProjectedCoordinateSystem(WktStreamTokenizer tokenizer)
{
/*PROJCS[
* "OSGB 1936 / British National Grid",
* GEOGCS[
* "OSGB 1936",
* DATUM[...]
* PRIMEM[...]
* AXIS["Geodetic latitude","NORTH"]
* AXIS["Geodetic longitude","EAST"]
* AUTHORITY["EPSG","4277"]
* ],
* PROJECTION["Transverse Mercator"],
* PARAMETER["latitude_of_natural_origin",49],
* PARAMETER["longitude_of_natural_origin",-2],
* PARAMETER["scale_factor_at_natural_origin",0.999601272],
* PARAMETER["false_easting",400000],
* PARAMETER["false_northing",-100000],
* AXIS["Easting","EAST"],
* AXIS["Northing","NORTH"],
* AUTHORITY["EPSG","27700"]
* ]
*/
tokenizer.ReadToken("[");
string name = tokenizer.ReadDoubleQuotedWord();
tokenizer.ReadToken(",");
tokenizer.ReadToken("GEOGCS");
IGeographicCoordinateSystem geographicCS = ReadGeographicCoordinateSystem(tokenizer);
tokenizer.ReadToken(",");
IProjection projection = ReadProjection(tokenizer);
IUnit unit = ReadLinearUnit(tokenizer);
string authority = String.Empty;
long authorityCode = -1;
tokenizer.NextToken();
List <AxisInfo> axes = new List <AxisInfo>(2);
if (tokenizer.GetStringValue() == ",")
{
tokenizer.NextToken();
while (tokenizer.GetStringValue() == "AXIS")
{
axes.Add(ReadAxis(tokenizer));
tokenizer.NextToken();
}
if (tokenizer.GetStringValue() == "AUTHORITY")
{
tokenizer.ReadAuthority(ref authority, ref authorityCode);
tokenizer.ReadToken("]");
}
}
//This is default axis values if not specified.
if (axes.Count == 0)
{
axes.Add(new AxisInfo("X", AxisOrientationEnum.East));
axes.Add(new AxisInfo("Y", AxisOrientationEnum.North));
}
IProjectedCoordinateSystem projectedCS = new ProjectedCoordinateSystem(geographicCS.HorizontalDatum, geographicCS, unit as LinearUnit, projection, axes, name, authority, authorityCode, String.Empty, String.Empty, String.Empty);
return(projectedCS);
}