## Reading IVOA Space-Time-Coordinates XML (STC-X) Descriptions

The XmlChanXmlChan class also provides support for reading (but not writing) XML documents which use a restricted subset of an early draft (V1.20) of the IVOA Space-Time-Coordinates XML (STC-X) system. The version of STC-X finally adopted by the IVOA differs in several significant respects from V1.20, and so the STC-X support currently provided by AST is mainly of historical interest. Note, AST also supports the alternative “STC-S” linear string description of the STC model (see §19).

STC-X V1.20 is documented at `http://www.ivoa.net/Documents/WD/STC/STC-20050225.html`, and the current version is documented at `http://www.ivoa.net/Documents/latest/STC-X.html`.

When an STC-X document is read using an XmlChan, the read operation produces an AST ObjectObject of the StcStc class, which is itself a subclass of RegionRegion. Specifically, each such Object will be an instance of StcSearchLocationStcSearchLocation, StcResourceProfileStcResourceProfile, StcCatalogEntryLocationStcCatalogEntryLocation or StcObsDataLocationStcObsDataLocation. See the description of the XmlChan class and the XmlFormatXmlFormat attribute for further details.