This page provides an overview of the Conceptual Modelling activity within the OGC Met Ocean DWG

Standards Incubation forum

MetOcean DWG forum: standards incubation

The OGC Met Ocean domain working group provides a forum within which contributing communties can work together to incubate new data exchange standards for the meteorology and oceanography community.

WMO-OGC memorandum of understanding (MoU) is instrumental in providing the mechanism for the co-ordination between activities carried out by the OGC Met Oceans DWG and Hydrology DWG, and the activities carried out by the expert teams of WMO CBS OPAG-ISS with a view to developing the use of ISO/OGC standards for the WIS.

The the main parties involved in driving the requirements for conceptual modelling activity are described here: ConceptualModellingConstiuents

Note: this is written from a WMO perspective - largely with the aim of harmonising initiatives across a number of communities.

Objective

Goals of conceptual modelling

Our goal is to establish a core conceptual model that meets the needs of our stakeholder community and maintains compatibility with existing data encodings such as GRIB, BUFR and netCDF – providing a mechanism to map content from one format to another.

A common conceptual model will enable tooling and software to sourced / provisioned from the breadth of the community that subscribes to the core conceptual model

Baseline - where do we start from?

If we wish to have interoperability with a range of OGC standards such as WMS, WCS, GML, WFS, Processing and Sensor related services, such as for vector meteorological data, we need to start looking at common underlying conceptual models and also 'application schemas'.

For example, a legally mandated presentation map layer may show an area of turbulence or cumulus cloud, but this area may have been drawn by a human, or may have been derived automatically from an underlying coverage grid, or even derived directly from a set of scattered observations. To ensure such seamless processing, the underlying conceptual models and derived schemas have to be consistent and unambiguous.

Following agreement by participants, 'ISO/DIS 19156 Geographic Information - Observations and Measurements' forms the basis of the conceptual model for meteorology and oceanography
WXXM2 convergence slide This slide is taken from a briefing to WXXM/AIXM Conference 04 May 2010, National Centre for Atmospheric Research (Aaron Braeckel) University Corporation for Atmospheric research. It suggests that there is significant community convergence around ISO/DIS 19156 Observations and Measurements - often referred to as *O&M2*
Observations and Measurements context

Best online tutorial resource can be found at the SEEGrid twiki

Although the specification title indications ‘observations’ it is equally valid for forecast phenomena – one is still using a procedure (i.e. numerical modelling) to estimate the value of a property of some feature of interest

The O&M model (and the accompanying Sampling Features models) have been successfully applied to a wide number of domains where the user community are interested in the ‘data-acquisition’ metadata – such as process, quality etc. Because O&M has been proven to be applicable to a wide number of domains, tooling and software developed for this model will also be widely applicable, increasing the likelihood that consumers of data conforming to this model will have tooling available to exploit its rich semantics.

Furthermore, the OGC has published a service specification: Sensor Observation Service (SOS) specifically to allow data conforming to the O&M model to be exploited through domain-agnostic tooling.

Note: the UML model diagram pictured above is from O&M 1.0 – some minor modifications are included for ISO/DIS 19156 (O&M 2.0) that improve the semantics associated with time to make them better aligned with representing forecast data

Methodology

The methodology adopted for the conceptual modelling activity is variant of INSPIRE methodology for developing conceptual models. This is detailed in INSPIRE document D2.6
Conceptual modelling methodology schematic

Use cases

Develop narrative based on realistic & focused user scenarios

Example datasets

Extract example datasets from existing (or postulated) workflows described within use cases

Validate model

Attempt to map content of datasets onto O&M model – identifying restrictions, constraints, controlled vocabularies

Check compatibility

Identify compatibility of existing encodings (BUFR, GRIB, CF-netCDF etc.). Develop conventions (or amendments) for their use with the common conceptual model … and hence compatibility of the common conceptual model with existing tooling and practices within the community

Additional details on the methodology can be found here: ConceptualModellingMethodology

-- JeremyTandy - 20 Apr 2011
Topic revision: r1 - 20 Apr 2011, JeremyTandy
 

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