The list of values supported for this option is identical to the list of parameters (including sub-parameters) documented
for the ST_AsXML method. See ST_AsXML method for type ST_Geometry.
This option is used to determine how a geometry is converted to XML. The following are the two main contexts in which the
option is used:
fetching a value as XML from a client application
Executing a CAST statement. For example: CAST( geometry-expression AS XML )
Assignments from geometry types to XML give an error in contexts other than fetching from a client application and the CAST
statement. For example, you cannot call a function or procedure that takes an XML parameter and pass a geometry, nor can you
assign a geometry to an XML variable.