/// <summary>
/// Checks whether the values of this instance is equal to the values of another instance.
/// Only parameters used for coordinate system are used for comparison.
/// Name, abbreviation, authority, alias and remarks are ignored in the comparison.
/// </summary>
/// <param name="obj"></param>
/// <returns>True if equal</returns>
public override bool EqualParams(object obj)
{
if (!(obj is SharpMap.CoordinateSystems.HorizontalDatum))
{
return(false);
}
HorizontalDatum datum = obj as HorizontalDatum;
if (datum.Wgs84Parameters == null && this.Wgs84Parameters != null)
{
return(false);
}
if (datum.Wgs84Parameters != null && !datum.Wgs84Parameters.Equals(this.Wgs84Parameters))
{
return(false);
}
return(datum.Ellipsoid == this.Ellipsoid && this.DatumType == datum.DatumType);
}
/// <summary>
///
/// </summary>
/// <param name="tokenizer"></param>
/// <returns></returns>
private static IHorizontalDatum 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"]]
Wgs84ConversionInfo wgsInfo = null;
string authority = String.Empty;
long authorityCode = -1;
tokenizer.ReadToken("[");
string name = tokenizer.ReadDoubleQuotedWord();
tokenizer.ReadToken(",");
tokenizer.ReadToken("SPHEROID");
IEllipsoid 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.
IHorizontalDatum horizontalDatum = new HorizontalDatum(ellipsoid, wgsInfo, DatumType.HD_Geocentric, name, authority, authorityCode, String.Empty, String.Empty, String.Empty);
return horizontalDatum;
}