19115 GeoJSON schema (+ Records?)

[rob-metalinkage]

          Hi All,

ISO TC 211 - working group 7 - Information Communities, is developing a JSON implementation of the 19115 metadata-standard, the 19115-4, Geographic information — Metadata — Part 4: JSON schema implementation of metadata fundamentals.

We are looking for help on creating a GeoJSON schema and want to put that into the Code-sprint

Our approach is the following:

• 19115-1 and 19157-1 (data quality) are in scope
• encoding will be in GeoJSON
• automated generation from uml to GeoJSON schema is possible, but will create an over-complex JSON schema which will be not fit for purpose
• a comprehensive XML 'real life' dataset is created and converted to a GeoJSON preferred encoding (this work is done)
• the GeoJSON example dataset is a subset (profile) of 19115-1 and 19157-1, but is considered to cover the essential part
• the GeoJSON example dataset is considered as the requirements that are set for the GeoJSON schema (to be developed)
• on the basis of this GeoJSON dataset and the conceptual UML model a GeoJSON schema needs to be generated.
• a first run of creating a GeoJSON schema from the conceptual UML is available but this needs to be reworked to fit the GeoJSON exmaple.

The goal set and work to be done is reworking the first concept of the GeoJSON schema on the basis of the agreed GeoJSON data example.

What is needed:

• JSON/GeoJSON expertise
• 19115 metadata domain knowledge
• hands on

Originally posted by @PalmJanssen in https://github.com/opengeospatial/GeoDCAT-SWG/issues/17#issuecomment-2437104168

[rob-metalinkage]

Suggested approach: the OGC provides Building Blocks for:

• GeoJSON
• Feature - for OGC API Features
• JSON-FG
• Records - for OGC API Records
• STAC.

Note that STAC implements Records implements Feature implements GeoJSON. This is not terribly obvious without reading each spec, particularly as they evolved at different times, but is explicit in the BuildingBlock packaging of these, and testable using schema declarations:

allOf:
- $ref: https://opengeospatial.github.io/bblocks/annotated-schemas/geo/features/feature/schema.yaml
- $ref: https://ogcincubator.github.io/bblocks-ogcapi-records/build/annotated/api/records/v1/schemas/recordGeoJSON/schema.yaml
- $ref: https://github.com/radiantearth/stac-spec/raw/master/item-spec/json-schema/item.json

Note also FG-JSON allows arbitrary CRS - so would support non-earth contexts - such as local crs or interplanetary applications. Perhaps more importantly it would allow much more sophisticated spatial and temporal extent declarations using DGGS geometries - critical for linear features, sparse coverages, polar regions and other applications not limited to simple local bounding areas.

Perhaps the biggest advantage of course would be this approach would automatically link to the GeoDCAT development work, inheriting the (extremely complex problem of) mapping these many and varied complex structures into a much more elegant semantic model common to all metadata models. This includes JSON-LD mapping and transformations, all testable.

The OGC COSI team will prioritise support for this activity, it would be reasonable to achieve an initial build of a development repository with automated testing and examples, inheriting from the available OGC Building Blocks. Such a build could identify key elements defined in ISO 19115 as requirements for GeoDCAT, and guide the Records->GeoDCAT mapping activities underway

[rob-metalinkage]

A repository has been established to document and test various starting points and solutions: https://github.com/ogcincubator/iso19115-json