gp-ogc-api-features

1. Data provider

BRGM (French Geological Survey) OFB (French Office for Biodiversity) through “INSIDE - environmental information systems research center”

2. Thematic scope

• French Surface Water
  • River gage:
    • INSPIRE EF:EnvironmentalMonitoringFacility
      • OGC API Feature : GeoJSON, GML, JSON-LD
  • River network
    • INSPIRE HY: HydroNode, WatercourseLink, WatercourseLinkSequence, Watercourse
      • OGC API Feature : GeoJSON, GML, JSON-LD (not configured yet)
  • Water flow/height Observation
    • ISO/OGC:Observations & Measurements (INSPIRE D2.9) -> OGC SensorThings API (ST API)
  • URI : references between EF <-> ST API
• French Hydrogeological data
  • Environmental Groundwater Quantity Monitoring Facility
    • INSPIRE EF:EnvironmentalMonitoringFacility
      • WFS 2 : DONE
      • OGC API Feature -> GeoJSON, GML, JSON-LD : conf on-going for API4INSPIRE project
  • Hydrogeological unit
    • OGC:GroundWaterML2.0 (mapped to INSPIRE GE:Hydrogeology package)
      • WFS 2 : DONE
      • OGC API Feature -> GeoJSON, GML, JSON-LD : conf on-going for API4INSPIRE project
  • Groundwater quantity Observation : groundwater level, temperature, conductivity
    • ISO/OGC:Observations & Measurements (INSPIRE D2.9) -> OGC SensorThings API (STA)
  • URI : references between EF <-> ST API

3. Envisaged use

Deployment and maturation in test environment on top of production system (data instances) within INSPIRE dynamics for API4INSPIRE project APIs will be transfered to production afterwards

• French Surface Water : Hub’Eau plateform https://hubeau.eaufrance.fr/
• French Hydrogeological data : BRGM information system

4. Requirements classes

• Requirement class http://inspire.ec.europa.eu/id/spec/oapif-download/1.0/req/pre-defined
• Requirement class (with issues - see below) http://inspire.ec.europa.eu/id/spec/oapif-download/1.0/req/geojson

TODO SG : X-check with the others

5. Server-side technology

Geoserver 2.17.2 for WFS 2.0 and OGC API Feature

• GML: app-schema plugin
• GeoJSON :
  • Now : using heuristics introduced in GeoServer core since 2.16.0 (see http://blog.geoserver.org/2019/09/18/geoserver-2-16-released/): GeoJSON generated from GML structure
  • Target : using Features-Templating community module (https://docs.geoserver.org/latest/en/user/community/features-templating/index.html) : available since end of Sept 2020
• JSON-LD : using the Features-Templating community module(initially using community module which is now integrated in the other) PostGre/GIS DB

Note : SensorThings API -> Fraunhofer FROST + PostGre/GIS DB

6. Endpoints and client applications

Test Endpoints are not fully opened. However via URI it partially works.

• Surface water example :
  • Feature Instance
    • https://iddata.eaufrance.fr/id/HydroStation/A021005050?f=application%2Fgeo%2Bjson
    • starting with HydroStation (=River gage) allows to also ask for ?f=application%2Fld%2Bjson, ou ?f=application%2Fgml%2Bxml (works also doing real content negotiation in tools like PostMan or cURL)
    • makes possible to traverse the hydro feature graph via featureOfInterest or ultimateFeatureOfInterest choosing between geojson or GML (JSON-LD not implemented yet)
    • makes it possible to access observation data using hasObservation (will provide application/JSON payload according to OGC ST API )
  • API endpoint : https://iddata.eaufrance.fr/api/hydrometryFAPI/ (not opened yet, will update this page as we go)
• Ground water example :
  • Feature Instance : TODO SG
  • API endpoint : TODO SG

Clients :

• Web
  • discussed in API4INSPIRE
  • dev ongoin at BRGM
• QGIS GML Application Schema toolbox for GML
  • starting to work on allowing to work on GeoJSON (not only GeoJSON serialization but also the ‘linked data’ part of the plugin)

7. Issues

• with http://inspire.ec.europa.eu/id/spec/oapif-download/1.0/req/geojson
  • provides harmonised data according to the [IRs for ISDSS -> needs to respect all the semantic work done in INSPIRE before even when moving to REST API providing other serialization as GML
  • “the Web API SHOULD follow the INSPIRE UML-to-GeoJSON encoding rule.”
    • examples here https://github.com/INSPIRE-MIF/2017.2/blob/master/GeoJSON/efs/simple-environmental-monitoring-facilities.md
      • come from BRGM WFS 2.0 app-schema endpoint (and SOS), not written by us (and not involved)
      • this is not how we are currently working to expose this in GeoJSON according to INSPIRE EF semantics (which we know pefectly)
      • moving to GeoJSON does not imply flattening everything !
      • that’s why we work on GeoJSON heuristics on Geoserver 2.16.0 then Features-Templating community module within API4INSPIRE project
• need harmonized pattern to provide references to other content in GeoJSON properties for proper client set-up
  • @id/@type/name : JSON-LD flavoured
  • id/type/name : the same but @ neutral
  • @href/@title : GML/XML flavoured (current Geoserver core heuristics for GML -> GeoJSON )
• Another issue is choice of encoding (corresponding issue: https://github.com/INSPIRE-MIF/gp-ogc-api-features/issues/53). This is not a blocker issue but real interoperability requires harmonised encoding.