Other attributes such as StcsArea and StcsProps can be used to specify other Objects to be returned by
AST_READ. If more than one of these attributes is set non-zero, then the actual Object returned by
AST_READ will be a KeyMap, containing the requested Objects. In this case, the PointList
representing the STC Coordinates will be stored in the returned KeyMap using the key
If StcsCoords is the only attribute to be set non-zero, then the Object returned by AST_READ will be
the Coordinates PointList itself.
The Coordinates component is specified by the additional axis values embedded within the body of
each STC-S sub-phrase that represents an extended area. Sub-phrases that represent a single value (
that is, have identifiers
" ) are not considered to be be
part of the STC Coordinates component.
If the STC-S documents does not contain a Coordinates component, then a NULL object pointer
(AST__NULL) will be returned by AST_READ if the Coordinates component is the only object being
returned. If other objects are also being returned (see attributes StcsProps and StcsArea), then the
returned KeyMap will contain a
" key only if the Coordinates component is read
The TimeFrame used to represent a time STC-S sub-phrase will have its TimeOrigin attribute set to the sub-phrase start time. If no start time is specified by the sub-phrase, then the stop time will be used instead. If no stop time is specified by the sub-phrase, then the single time value specified in the sub-phrase will be used instead. Subsequently clearing the TimeOrigin attribute (or setting its value to zero) will cause the TimeFrame to reprsent absolute times.