metadata samplingFeatureMember observationMember temporalExtent Extension community and internal

Copyright © 2012 Open Geospatial Consortium 70 The collection class also allows for local definitions of codes, such as quality codes and qualifiers. The local dictionaries are a convenience to allow elements that normally reside in code lists to be specified locally in the document. There are two benefits to this: it allows metadata to be provided alongside each code item; and it allows more compact encoding for code list items that need to be referenced regularly. The contents of a collection will be determined by the scenario in which it is used; some examples include: Web service responses Transactional updates Groups of model outputs ensemble models The collection class may be replaced by services that already define such collections - such as in the Sensor Observation Service - but the model may be used as a guide to the content of collections.

9.23.1 metadata

Describes the metadata associated with the document. See section 9.23.7 for the definition of DocumentMetadata.

9.23.2 samplingFeatureMember

This property allows for multiple sampling features to be described within the document. The feature member may also be a sampling feature collection SF_SamplingFeatureCollection.

9.23.3 observationMember

This property allows for multiple TimeseriesObservation members to be included in the collection document.

9.23.4 temporalExtent

Describes the temporal extent of the all the observation members that exist in the document.

9.23.5 Extension community and internal

The communityExtension and internalExtension properties provide a schema extension point that allows new schema types to be used if required. The Any type allows elements from other namespaces to be included. The community extension should be used to place extension types that have been agreed upon by a community such as the Hydro Domain Working Group; the internal extension allows organisations to use internal extensions without affecting agreed on extensions. OGC WaterML 2.0 OGC 10-126r3 Copyright © 2012 Open Geospatial Consortium 71

9.23.6 Local dictionaries