OGC Oceans Science Interoperability Experiment

The Oceans Science Interoperability Experiment is a collaboration of the Ocean-Observing community to enhance the community's understanding of various OGC standards, solidify demonstrations for Ocean Science application areas, harden software implementations, and produce candidate OGC Best Practices document that can be used to inform the broader ocean-observing community. To achieve these goals, the Oceans IE will engage the OGC membership to assure that any community recommendations coming from the Oceans group will properly leverage the OGC standards. Potentially, Change Requests for existing OGC Standards will be provided to the OGC Technical Committee to influence the underlying standards.

Starting in late 2007, the first phase of the Ocean IE focused on these areas:

• Web Services for Interoperable Ocean Science.
• Sensor Web Enablement (SWE) in particular Observations & Measurements and SensorML.
• Web Feature Service (WFS) for accessing raw sensor observations
• Sensor Observation Service (SOS) for accessing raw sensor observations observations.

The results of Phase 1 of the Oceans IE were documented in an OGC approved report. The following is a summary of the findings and experiments:

The Oceans IE Phase I investigated the use of OGC Web Feature Services (WFS) and OGC Sensor Observation Services (SOS) for representing and exchanging point data records from fixed in-situ marine platforms. It concluded that the use of OGC Sensor Observation Services (SOS) was better suited than the use of OGC Web Feature Services (WFS) for this purpose. By publishing an SOS service instead of a WFS service communities will not required to create and maintain schemas, and interoperability at the client side is achieved; however this requires an effort in creating and maintaining controlled vocabularies by marine communities.

The Oceans IE developed the following best practices for using an OGC Sensor Observation Service (1.1), which will help improve existing standards and recommendations at OGC:

• Requesting a get latest observation
• Encoding of OGC URNs when versioning is missing
• Publishing of URIs by service providers
• Using Semantic Web technologies to categorize SOS services
• Publishing an SOS as an HTTP-Get service
• Encoding vertical datums (Sea level based systems, geoid based systems and bottom based systems) in marine observations

Also, the OOSTethys team, developed a set of toolkits to help service providers publish SOS services. The toolkits are in Java, Perl and Python and follow the best practices detailed in this document. The toolkits are available at http://www.oostethys.org.

The second phase of the Oceans IE was approved in January 2009 and official began in March 2009. Oceans IE Phase II will address issues that arose in Phase 1, including: an encoding standard for trajectories (of, for example, autonomous underwater vehicles); long time series services; services involving complex systems; and services that are event based (e.g. tsunami sensors within +/-12 hrs of an tsunami) and others.