Align with OGC SDW/Geosemantics activities with SOSA

[rob-metalinkage]

At the 2023 Frascati meeting the Spatial Data on the Web Working Group discussed the future of the SOSA ontology, and further discussed (as reported) in the OMS SWG. The SOSA update process is operating on the basis of SOSA implementing OMS scope and semantics as the canonical semantic expression. [1]

Two other activities were discussed and put on the roadmap - developing common models for observedProperty descriptions and an OGC API Features compatible JSON schema.

This work has progressed to provide implementations of Observation and Observation Collection[2], with a modular approach including a binding to GeoJSON and the new Feature-Geometry [3] JSON Feature and FeatureCollection schemas. These use the OGC Building Block approach [4] which supports both integrated testing of examples but also executable alignments between schemas and ontologies via JSON-LD contexts.

This implementation has been included in multiple projects, and provides the critical opportunity for "evidence of implementation" required for the new OMS alignments in SOSA.

This work already includes direct references to the underlying published OGC API schemas - which is important to note - because the OAS 3.0 baseline of the OGC APIs uses a very old (and modified version) of JSON schema that does not support relative paths to components of imported schemas - so most implementations have anonymous copies of such schemas. The BBlock tooling supported OAS 3.1 with "transparent references" and an automated back-port to 3.0 compatible bundled schemas. It also supports example validation, use of SHACL (and other validators) for logical consistency rules and testing of transformations to related models. All these functions come "out-of-the-box".

So, a "developer" view of this for publishing an OMS API based on these foundations could leverage this work and avoid duplication and inconsistencies. Given this work is already being adopted by other projects, its seems the only feasible pathway to achieve necessary testing for the SOSA update timeline (April 2024)

[1] https://w3c.github.io/sdw-sosa-ssn/ssn/#OMS_alignment
[2] https://github.com/opengeospatial/ogcapi-sosa
[3] https://github.com/opengeospatial/ogc-feat-geo-json
[4] https://github.com/opengeospatial/bblock-template