processType processReference verticalDatum aggregationDuration parameter operator

OGC WaterML 2.0 OGC 10-126r3 Copyright © 2012 Open Geospatial Consortium 67 Quality assurance related tasks such as automatic spike removal or gap filling; Derivation of new “observed phenomena” such as calculation of volume from stage, discharge flow from stage etc. These operations are performed on raw observational data to create separate data products more appropriate for particular types of reporting, ingestion into models, or for archival purposes. Maintaining information on the procedure used in the creation of a new ‘observation’ is important for correct interpretation of an observations result. Note here that the data being described is not strictly an observation but the OM model is appropriate for such description, and encourages such use: “An instance of OM_Process is often an instrument or sensor, but may be a human observer, a simulator, or a process or algorithm applied to more primitive results used as inputs.” WaterML2 defines an ObservationProcess feature type. This a generic class to describe processes related to the creation of hydrological results. Table 8 - available types of processes Process type OGC Name Simulation http:www.opengis.netdefwaterml2.0processTypeSimulation Manual Method http:www.opengis.netdefwaterml2.0processTypeManualMethod Sensor http:www.opengis.netdefwaterml2.0processTypeSensor Algorithm http:www.opengis.netdefwaterml2.0processTypeAlgorithm Unknown http:www.opengs.netdefnilOGC0unknown The following sections describe the properties available in ObservationProcess.

9.22.1 processType

Identifies the process type that was used to generate this observation. The available process types are listed in Table 8. Note that this should be the last process that operated on the observation. The original source of the data should be identified using the originalSource property.

9.22.2 processReference

A reference to an external process that was used. This could be the specification sheet for a sensor, a piece of code implementing an algorithm, or a reference to a methods repository, such as National Environmental Method Index https:www.nemi.gov . Copyright © 2012 Open Geospatial Consortium 68

9.22.3 verticalDatum

A datum reference is available here a property also exists in the description of monitoring points, see section 9.19 for cases where the vertical datum used for level measurements differs from the datum associated with the monitoring point. The CD_VerticalDatum type allows specification of the local gauge zero as a height above a reference datum. E.g. local gauge zero is 23m above the AHD.

9.22.4 aggregationDuration

If the process involves temporal aggregation of a result set, the time duration over which data has been aggregated should be expressed here. E.g. hourly, daily aggregates.

9.22.5 parameter

A soft-typed parameter to allow arbitrary properties to be added to the description. This property uses the name-value type from ISO19156.

9.22.6 operator

Describes the party responsible for performing the process. E.g. the person performing the method or operating the sensor.

9.22.7 comment