/// <summary>
/// Returns a IUnit 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 Unit ReadUnit(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 Unit()
{
Id = authorityCode + "", Name = unitName, Abbreviation = unitName, ConversionFactor = unitsPerUnit
});
}
/// <summary>
/// 读取 HorizontalDatum
/// </summary>
/// <param name="tokenizer"></param>
/// <returns></returns>
private static HorizontalDatum ReadHorizontalDatum(WktStreamTokenizer tokenizer)
{
//DATUM["OSGB 1936",SPHEROID["Airy 1830",6377563.396,299.3249646,AUTHORITY["EPSG","7001"]],TOWGS84[0,0,0,0,0,0,0],AUTHORITY["EPSG","6277"]]
BursaTransParams wgsInfo = null;
string authority = String.Empty;
long authorityCode = -1;
tokenizer.ReadToken("[");
string name = tokenizer.ReadDoubleQuotedWord();
tokenizer.ReadToken(",");
tokenizer.ReadToken("SPHEROID");
Ellipsoid ellipsoid = ReadEllipsoid(tokenizer);
tokenizer.NextToken();
while (tokenizer.GetStringValue() == ",")
{
tokenizer.NextToken();
if (tokenizer.GetStringValue() == "TOWGS84")
{
wgsInfo = ReadWGS84ConversionInfo(tokenizer);
tokenizer.NextToken();
}
else if (tokenizer.GetStringValue() == "AUTHORITY")
{
tokenizer.ReadAuthority(ref authority, ref authorityCode);
tokenizer.ReadToken("]");
}
}
// make an assumption about the datum type.
HorizontalDatum horizontalDatum = new HorizontalDatum(
ellipsoid,
wgsInfo,
DatumType.HD_Geocentric,
name,
authorityCode + "");
return(horizontalDatum);
}
/// <summary>
///
/// </summary>
/// <param name="tokenizer"></param>
/// <returns></returns>
private static PrimeMeridian 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.
PrimeMeridian primeMeridian = new PrimeMeridian(longitude, AngularUnit.Degree, name, authorityCode + "");
return(primeMeridian);
}
/// <summary>
///
/// </summary>
/// <param name="tokenizer"></param>
/// <returns></returns>
private static GeographicCs ReadGeographicCoordinateSystem(WktStreamTokenizer tokenizer)
{
/*
* GEOGCS["OSGB 1936",
* DATUM["OSGB 1936",SPHEROID["Airy 1830",6377563.396,299.3249646,AUTHORITY["EPSG","7001"]],TOWGS84[0,0,0,0,0,0,0],AUTHORITY["EPSG","6277"]]
* PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]]
* AXIS["Geodetic latitude","NORTH"]
* AXIS["Geodetic longitude","EAST"]
* AUTHORITY["EPSG","4277"]
* ]
*/
tokenizer.ReadToken("[");
string name = tokenizer.ReadDoubleQuotedWord();
tokenizer.ReadToken(",");
tokenizer.ReadToken("DATUM");
HorizontalDatum horizontalDatum = ReadHorizontalDatum(tokenizer);
tokenizer.ReadToken(",");
tokenizer.ReadToken("PRIMEM");
PrimeMeridian primeMeridian = ReadPrimeMeridian(tokenizer);
tokenizer.ReadToken(",");
tokenizer.ReadToken("UNIT");
AngularUnit angularUnit = ReadAngularUnit(tokenizer);
string authority = String.Empty;
long authorityCode = -1;
tokenizer.NextToken();
List <IAxis> info = new List <IAxis>(2);
if (tokenizer.GetStringValue() == ",")
{
tokenizer.NextToken();
while (tokenizer.GetStringValue() == "AXIS")
{
info.Add(ReadAxis(tokenizer));
tokenizer.NextToken();
if (tokenizer.GetStringValue() == ",")
{
tokenizer.NextToken();
}
}
if (tokenizer.GetStringValue() == ",")
{
tokenizer.NextToken();
}
if (tokenizer.GetStringValue() == "AUTHORITY")
{
tokenizer.ReadAuthority(ref authority, ref authorityCode);
tokenizer.ReadToken("]");
}
}
//This is default axis values if not specified.
if (info.Count == 0)
{
info.Add(new Axis("Lon", Direction.East));
info.Add(new Axis("Lat", Direction.North));
}
GeographicCs geographicCS = new GeographicCs(angularUnit, horizontalDatum,
primeMeridian, info, name, authorityCode + "");
return(geographicCS);
}
/// <summary>
///
/// </summary>
/// <param name="tokenizer"></param>
/// <returns></returns>
private static ProjectedCs 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");
GeographicCs geographicCS = ReadGeographicCoordinateSystem(tokenizer);
tokenizer.ReadToken(",");
Projection projection = ReadProjection(tokenizer);
Unit unit = ReadLinearUnit(tokenizer);
string authority = String.Empty;
long authorityCode = -1;
tokenizer.NextToken();
List <IAxis> axes = new List <IAxis>(2);
if (tokenizer.GetStringValue() == ",")
{
tokenizer.NextToken();
while (tokenizer.GetStringValue() == "AXIS")
{
axes.Add(ReadAxis(tokenizer));
tokenizer.NextToken();
if (tokenizer.GetStringValue() == ",")
{
tokenizer.NextToken();
}
}
if (tokenizer.GetStringValue() == ",")
{
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 Axis("X", Direction.East));
axes.Add(new Axis("Y", Direction.North));
}
ProjectedCs projectedCS = new ProjectedCs(geographicCS.HorizontalDatum, geographicCS, unit as LinearUnit, projection, axes, name, authorityCode + "");
return(projectedCS);
}