The 'Observable Property' model enables observed physical properties to be aggregated into composite properties and for any qualification or constraint relating to the observed physical properties to be explicitly described.<br /></p><p><br /></p><p>A data publisher may need to use the Observed Property model  to explicitly define any qualification or constraint applied to the observed property, or, where the observation results in the evaluation of multiple properties, to explicitly define each of those individual physical properties.<br /></p><p><br /></p><p>OM_Observation/parameter can be used to specify the ObservableProperty via the soft-typed NamedValue class.<br /></p><p><br /></p><p>The appropriate semantics are found in the GF_AssociationRole 'property' within the Observable Property model; the valueType is specified as AbstractObservableProperty enabling an instance of either CompositeObservableProperty -OR- ObservableProperty to be referenced. <br /></p><p><br /></p><p>NamedValue/name is specified as Type 'GenericName'. To enable software systems to identify the ObservedProperty entities when parsing the observation, 'name' must be specified consistently.<br /></p><p><br /></p><p>Assuming that the Observed Property model is published within a Feature Type Catalogue as part of WMO METCE as an instance of FC_AssociationRole, GF_AssociationRole 'property' will be identified with the HTTP URI http://data.wmo.int/def/observable-property/property.<br /></p><p><br /></p><p>NamedValue/value is specified as Type 'Any'. In this case, 'value' shall be defined as either of the concrete subclasses of AbstractObservableProperty, conforming to the semantics of GF_AssociationRole 'property'. <br /></p><p><br /></p><p>Example:<br /></p><p><parameter><br /></p><p>    <NamedValue><br /></p><p>        <name> http://data.wmo.int/def/observable-property/property </name><br /></p><p>        <value> <br /></p><p>            <QualifiedObservableProperty><br /></p><p>                <label> Maximum UV Index measured over previous 3-hours </label><br /></p><p>                <notation> maxUVIndex_3hr </notation><br /></p><p>                <baseProperty xlink:href="http://data.wmo.int/def/quantities/UVIndex" xlink:title="UV Index" /><br /></p><p>                <qualifier><br /></p><p>                    <StatisticalQualifier><br /></p><p>                        <aggregationTimePeriod> PT3H </aggregationTimePeriod><br /></p><p>                        <statisticalFunction xlink:href="http://data.wmo.int/def/bufr-codeflag/0-08-023_2" xlink:title="Maximum" /><br /></p><p>                    </StatisticalQualifier><br /></p><p>                </qualifier><br /></p><p>            </QualifiedObservableProperty><br /></p><p>        </value><br /></p><p>    </NamedValue><br /></p><p></parameter><br /></p>