The Geometry Data Service (GDS) provides APIs for serving (spatial) geometries as RESTful separable first-class objects to spatial features over the web. The GDS provides access to multiple views of spatial geometries for the relevant reporting geographies included in Loc-I as Linked Data. Geometry data is provided in different forms (e.g. geometry as-is, centroid, metadata-only) and formats/serialisations (e.g. WKT, GeoJSON, SHP, RDF/GeoSPARQL). The GDS achieves this via Content Negotiation on spatial features stored in the Loc-I Geo-database, which hosts the geometries. This allows spatial features in Loc-I to embed URI-references to the geometry instead of embedding a geometry literal, optimising the RDF graph store for semantic queries rather than geospatial.
Background to the GDS can be found at the original geometry data service github issue.
See this link to the API for the OpenAPI spec.
| MIME Type | Description | Returns |
|---|---|---|
| text/html | Web interface | <!DOCTYPE html><html lang="en">... |
| text/plain | Well-Known Text | POLYGON((113.1016 -38.062 ...)) |
| application/json | GeoJSON | {"type":"Polygon","coordinates":...} |
| text/turtle | RDF Turtle representation using GeoSPARQL | _:geom1 a geo:sfPolygon , geo:Geometry ; geo:asWKT "POLYGON((113.1016 -38.062 ...))"^^geo:wktLiteral . |
Future work:
| MIME Type | Description | Returns |
|---|---|---|
| application/geo+json | GeoJSON | {"type":"Polygon","coordinates":...} |
| application/gml+xml | GML | <gml:Polygon><gml:Exterior>... |
| application/octet-stream | Well-Known Binary | 01 06 00 00 20 E6 10 00 00 01... |
Note: The above views extend a specification proposed by Regalia et al. 2017*.