AbstractFeatureMemberType and derived property types

Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved. 55 This clause describes the schema components for geometric primitives as specified by GML. NOTE 2 The corresponding geometry schema documents, geometryBasic0d1d.xsd, geometryBasic2d.xsd and geometryPrimitives.xsd see Annex C, are identified by the following location-independent names using URN syntax: urn:x-ogc:specification:gml:schema-xsd:geometryBasic0d1d:3.2.1 urn:x-ogc:specification:gml:schema-xsd:geometryBasic2d:3.2.1 urn:x-ogc:specification:gml:schema-xsd:geometryPrimitives:3.2.1 Any geometry element that inherits the semantics of gml:AbstractGeometryType may be viewed as a set of direct positions. All of the classes derived from gml:AbstractGeometryType inherit an optional association to a coordinate reference system. All direct positions shall directly or indirectly be associated with a coordinate reference system. When geometry elements are aggregated in another geometry element such as a gml:MultiGeometry or gml:GeometricComplex, which already has a coordinate reference system specified, then these elements are assumed to be in that same coordinate reference system unless otherwise specified. The geometry model distinguishes geometric primitives, aggregates and complexes. Geometric primitives, i.e. instances of a subtype of gml:AbstractGeometricPrimitiveType, will be open, that is, they will not contain their boundary points; curves will not contain their end points, surfaces will not contain their boundary curves, and solids will not contain their bounding surfaces.

10.1.2 Relationship with ISO 19107

The spatial geometry components of the GML schema specified in Clauses 10 and 11 provide a conformant, partial implementation of the ISO 19107 spatial schema geometry. The relationship is discussed in detail in D.2.3. The ISO 19107 geometry types implemented in GML are specified in ISO 19107; some additional constraints are specified in ISO 19107 for these types, which are also constraints on the spatial geometry components of the GML schema. In addition, GML specifies complementary spatial geometry schema components as described in D.3.5 to D.3.8. 10.1.3 Abstract geometry 10.1.3.1 AbstractGeometryType complexType name=AbstractGeometryType abstract=true complexContent extension base=gml:AbstractGMLType attributeGroup ref=gml:SRSReferenceGroup extension complexContent complexType All geometry elements are derived directly or indirectly from this abstract supertype. A geometry element shall have an identifying attribute gml:id, may have one or more names elements gml:identifier and