geometry.xsd v2.05a 2001-06 GML Geometry schema. Copyright (c) 2001 OGC, All Rights Reserved. Modified to comply with http://www.w3.org/2001/XMLSchema. Support for null-able and empty geometries has been added. All geometry elements are derived from this abstract supertype; a geometry element may have an identifying attribute ('gid'). It may be associated with a spatial reference system. This abstract base type for geometry collections just makes the srsName attribute mandatory. These attributes can be attached to any element, thus allowing it to act as a pointer. The 'remoteSchema' attribute allows an element that carries link attributes to indicate that the element is declared in a remote schema rather than by the schema that constrains the current document instance. A geometryMember encapsulates any primitive geometry element. Alternatively, it can function as a simple link that points to a remote geometry. A Point is defined by a single coordinate tuple. A LineString is defined by two or more coordinate tuples, with linear interpolation between them. A LinearRing is defined by four or more coordinate tuples, with linear interpolation between them; the first and last coordinates must be coincident. The Box structure defines an extent using a pair of coordinate tuples. A Polygon is defined by an outer boundary and zero or more inner boundaries which are in turn defined by LinearRings. A geometry collection must include one or more geometries, referenced through geometryMember elements. User-defined geometry collections that accept GML geometry classes as members must instantiate--or derive from--this type. A MultiPoint is defined by one or more Points, referenced through pointMember elements. A MultiLineString is defined by one or more LineStrings, referenced through lineStringMember elements. A MultiPolygon is defined by one or more Polygons, referenced through polygonMember elements. Represents a coordinate tuple in one, two, or three dimensions. Coordinates can be included in a single string, but there is no facility for validating string content. The value of the 'cs' attribute is the separator for coordinate values, and the value of the 'ts' attribute gives the tuple separator (a single space by default); the default values may be changed to reflect local usage.