VerticalDatum VerticalDatumPropertyType Other concrete datums .1 EngineeringDatum

Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved. 123

12.5.4.8 TemporalDatum, origin

element name=TemporalDatum type=gml:TemporalDatumType substitutionGroup=gml:AbstractDatum complexType name=TemporalDatumType complexContent extension base=gml:TemporalDatumBaseType sequence element ref=gml:origin sequence extension complexContent complexType complexType name=TemporalDatumBaseType abstract=true complexContent restriction base=gml:AbstractDatumType sequence element ref=gml:metaDataProperty minOccurs=0 maxOccurs=unbounded element ref=gml:description minOccurs=0 element ref=gml:descriptionReference minOccurs=0 element ref=gml:identifier element ref=gml:name minOccurs=0 maxOccurs=unbounded element ref=gml:remarks minOccurs=0 element ref=gml:domainOfValidity minOccurs=0 element ref=gml:scope maxOccurs=unbounded sequence attribute ref=gml:id use=required restriction complexContent complexType A gml:TemporalDatum defines the origin of a Temporal Reference System. This type omits the anchorDefinition and realizationEpoch elements and adds the origin element with the dateTime type. The TemporalDatumBaseType partially defines the origin of a temporal coordinate reference system. This type restricts the AbstractDatumType to remove the anchorDefinition and realizationEpoch elements. element name=origin type=dateTime gml:origin is the date and time origin of this temporal datum. The metaDataProperty element has been deprecated, and the gml:description element has been partially deprecated.

12.5.4.9 TemporalDatumPropertyType

complexType name=TemporalDatumPropertyType sequence minOccurs=0 element ref=gml:TemporalDatum sequence attributeGroup ref=gml:AssociationAttributeGroup complexType gml:TemporalDatumPropertyType is a property type for association roles to a temporal datum, either referencing or containing the definition of that datum. 124 Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved.

12.6 Coordinate operations

12.6.1 Overview

The spatial or temporal coordinate operations schema components can be divided into five logical parts, which define elements and types for XML encoding of the definitions of:  Multiple abstract coordinate operations  Multiple concrete types of coordinate operation, including Transformations and Conversions  Abstract and concrete parameter values and groups  Operation methods  Abstract and concrete operation parameters and groups These schema components encode the Coordinate Operation package of the UML Model for ISO 19111:2007, Clause 11. NOTE The coordinateOperations schema includes the coordinateOperations.xsd GML schema document. This schema document is identified by the following location-independent name using URN syntax: urn:x-ogc:specification:gml:schema-xsd:coordinateOperations:3.2.1 12.6.2 Abstract coordinate operations 12.6.2.1 AbstractCoordinateOperation element name=AbstractCoordinateOperation type=gml:AbstractCoordinateOperationType abstract=true substitutionGroup=gml:Definition complexType name=AbstractCoordinateOperationType abstract=true complexContent extension base=gml:IdentifiedObjectType sequence element ref=gml:domainOfValidity minOccurs=0 element ref=gml:scope maxOccurs=unbounded element ref=gml:operationVersion minOccurs=0 element ref=gml:coordinateOperationAccuracy minOccurs=0 maxOccurs=unbounded element ref=gml:sourceCRS minOccurs=0 element ref=gml:targetCRS minOccurs=0 sequence extension complexContent complexType gml:AbstractCoordinateOperation is a mathematical operation on coordinates that transforms or converts coordinates to another coordinate reference system. Many but not all coordinate operations from CRS A to CRS B also uniquely define the inverse operation from CRS B to CRS A. In some cases, the operation method algorithm for the inverse operation is the same as for the forward algorithm, but the signs of some operation parameter values shall be reversed. In other cases, different algorithms are required for the forward and inverse operations, but the same operation parameter values are used. If some entirely different parameter values are needed, a different coordinate operation shall be defined.