Metacat

<?xml version="1.0" encoding="UTF-8"?>

<schema targetNamespace="http://www.opengis.net/gml/3.2" xmlns:gml="http://www.opengis.net/gml/3.2" xmlns="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" version="3.2.1.2">

	<annotation>

		<appinfo source="urn:x-ogc:specification:gml:schema-xsd:dynamicFeature:3.2.1">dynamicFeature.xsd</appinfo>

		<documentation>See ISO/DIS 19136 15.6.

A number of types and relationships are defined to represent the time-varying properties of geographic features. 

In a comprehensive treatment of spatiotemporal modeling, Langran (see Bibliography) distinguished three principal temporal entities: states, events, and evidence; the schema specified in the following Subclauses incorporates elements for each.

GML is an OGC Standard.

Copyright (c) 2007,2010 Open Geospatial Consortium.

To obtain additional rights of use, visit http://www.opengeospatial.org/legal/ .

		</documentation>

	</annotation>

	<include schemaLocation="gml.xsd"/>

	<include schemaLocation="feature.xsd"/>

	<include schemaLocation="direction.xsd"/>

	<element name="dataSource" type="gml:StringOrRefType">

		<annotation>

			<documentation>Evidence is represented by a simple gml:dataSource or gml:dataSourceReference property that indicates the source of the temporal data. The remote link attributes of the gml:dataSource element have been deprecated along with its current type.</documentation>

		</annotation>

	</element>

	<element name="dataSourceReference" type="gml:ReferenceType">

		<annotation>

			<documentation>Evidence is represented by a simple gml:dataSource or gml:dataSourceReference property that indicates the source of the temporal data.</documentation>

		</annotation>

	</element>

	<group name="dynamicProperties">

		<annotation>

			<documentation>A convenience group. This allows an application schema developer to include dynamic properties in a content model in a standard fashion.</documentation>

		</annotation>

		<sequence>

			<element ref="gml:validTime" minOccurs="0"/>

			<element ref="gml:history" minOccurs="0"/>

			<element ref="gml:dataSource" minOccurs="0"/>

			<element ref="gml:dataSourceReference" minOccurs="0"/>

		</sequence>

	</group>

	<element name="DynamicFeature" type="gml:DynamicFeatureType" substitutionGroup="gml:AbstractFeature">

		<annotation>

			<documentation>States are captured by time-stamped instances of a feature. The content model extends the standard gml:AbstractFeatureType with the gml:dynamicProperties model group.

Each time-stamped instance represents a 'snapshot' of a feature. The dynamic feature classes will normally be extended to suit particular applications.  A dynamic feature bears either a time stamp or a history.</documentation>

		</annotation>

	</element>

	<complexType name="DynamicFeatureType">

		<complexContent>

			<extension base="gml:AbstractFeatureType">

				<group ref="gml:dynamicProperties"/>

			</extension>

		</complexContent>

	</complexType>

	<element name="DynamicFeatureCollection" type="gml:DynamicFeatureCollectionType" substitutionGroup="gml:DynamicFeature">

		<annotation>

			<documentation>A gml:DynamicFeatureCollection is a feature collection that has a gml:validTime property (i.e. is a snapshot of the feature collection) or which has a gml:history property that contains one or more gml:AbstractTimeSlices each of which contain values of the time varying properties of the feature collection.  Note that the gml:DynamicFeatureCollection may be one of the following:

1.	A feature collection which consists of static feature members (members do not change in time) but which has properties of the collection object as a whole that do change in time .  

2.	A feature collection which consists of dynamic feature members (the members are gml:DynamicFeatures) but which also has properties of the collection as a whole that vary in time.</documentation>

		</annotation>

	</element>

	<complexType name="DynamicFeatureCollectionType">

		<complexContent>

			<extension base="gml:DynamicFeatureType">

				<sequence>

					<element ref="gml:dynamicMembers"/>

				</sequence>

			</extension>

		</complexContent>

	</complexType>

	<element name="dynamicMembers" type="gml:DynamicFeatureMemberType"/>

	<complexType name="DynamicFeatureMemberType">

		<complexContent>

			<extension base="gml:AbstractFeatureMemberType">

				<sequence>

					<element ref="gml:DynamicFeature" minOccurs="0" maxOccurs="unbounded"/>

				</sequence>

				<attributeGroup ref="gml:AssociationAttributeGroup"/>

			</extension>

		</complexContent>

	</complexType>

	<element name="AbstractTimeSlice" type="gml:AbstractTimeSliceType" abstract="true" substitutionGroup="gml:AbstractGML">

		<annotation>

			<documentation>To describe an event — an action that occurs at an instant or over an interval of time — GML provides the gml:AbtractTimeSlice element. A timeslice encapsulates the time-varying properties of a dynamic feature -- it shall be extended to represent a time stamped projection of a specific feature. The gml:dataSource property describes how the temporal data was acquired.

A gml:AbstractTimeSlice instance is a GML object that encapsulates updates of the dynamic—or volatile—properties that reflect some change event; it thus includes only those feature properties that have actually changed due to some process.

gml:AbstractTimeSlice basically provides a facility for attribute-level time stamping, in contrast to the object-level time stamping of dynamic feature instances. 

The time slice can thus be viewed as event or process-oriented, whereas a snapshot is more state or structure-oriented. A timeslice has richer causality, whereas a snapshot merely portrays the status of the whole. 

</documentation>

		</annotation>

	</element>

	<complexType name="AbstractTimeSliceType" abstract="true">

		<complexContent>

			<extension base="gml:AbstractGMLType">

				<sequence>

					<element ref="gml:validTime"/>

					<element ref="gml:dataSource" minOccurs="0"/>

				</sequence>

			</extension>

		</complexContent>

	</complexType>

	<element name="history" type="gml:HistoryPropertyType">

		<annotation>

			<documentation>A generic sequence of events constitute a gml:history of an object.

The gml:history element contains a set of elements in the substitution group headed by the abstract element gml:AbstractTimeSlice, representing the time-varying properties of interest. The history property of a dynamic feature associates a feature instance with a sequence of time slices (i.e. change events) that encapsulate the evolution of the feature.</documentation>

		</annotation>

	</element>

	<complexType name="HistoryPropertyType">

		<sequence>

			<element ref="gml:AbstractTimeSlice" maxOccurs="unbounded"/>

		</sequence>

		<attributeGroup ref="gml:OwnershipAttributeGroup"/>

	</complexType>

</schema>