gmlBase.xsd

See ISO/DIS 19136 7.2.
The gmlBase schema components establish the GML model and syntax, in particular
-	a root XML type from which XML types for all GML objects should be derived,
-	a pattern and components for GML properties,
-	patterns for collections and arrays, and components for generic collections and arrays,
-	components for associating metadata with GML objects,
-	components for constructing definitions and dictionaries.