Rules for referencing GML profiles from application schemas

Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved. 225 comprise the standard GML distribution. The schema document gml.xsd is an exhaustive superset following the latter approach.

20.7 Summary of rules for GML profiles

In summary, the rules for a profile:  A profile of GML is a logical restriction of a subset of GML.  A profile shall not change the name, definition, or data type of mandatory GML elements or attributes.  The relevant schema or schemas that define a profile shall use in the core ‗gml‘ namespace http:www.opengis.netgml3.2.  An application schema may extend and use types from the profile, but shall do so in its own namespace, and not use http:www.opengis.netgml3.2. The functional test of these rules is: Any instance document for an application schema using a GML profile will be valid against the same application schema if the GML profile is replaced by the complete GML schema. Further, the interpretation of that document would be the same regardless of which of the two schemas were used. 21 Rules for GML application schemas

21.1 Instances of GML objects

21.1.1 GML documents

An XML document contains a single XML element as its root. A GML document may be one of the following elements:  A gml:AbstractFeature or any element directly or indirectly in its substitution group. NOTE 1 This includes feature collections and coverages as both are features, too.  A gml:Dictionary or any element directly or indirectly in its substitution group. NOTE 2 This includes coordinate reference system and units dictionaries.  A gml:TopoComplex or any element directly or indirectly in its substitution group. The standard methods for XML documents based on W3C XML Schema provide that the XML namespaces used in a document are declared as attributes within the document, and the location of schema documents that provide the source components for each namespace may be indicated. For a GML document, the source of the components describing the primary components within the document is a GML application schema. Both the document type and the associated GML application schema are described in this Clause.