Enhance asDGGS with DGG ID

[nicholascar]

For the literal asDGGS, no equivalent of asWKT 's CRS is given so there's no way to know what DGGS the cell identifiers are for.

Since we now have at least one PID for a DGGS grid - https://w3id.org/dggs/tb16pix for TB 16 Pix - we can use this as a DGG identifier.

I propose an enhancement to the asDGGS, as per asWKT:

• simple: "R7430550 R7430551 R7430552"
• with DGG ID: "<https://w3id.org/dggs/tb16pix> R7430550 R7430551 R7430552" -- for TB16Pix in this case

[dr-shorthair]

@nicholascar Where is the ontology used for the RDF encoding of this DGGS ontology documented? https://w3id.org/dggs/abstract/ont/ does not dereference.

Were you aware of what we'd already done here - http://linked.data.gov.au/def/auspix ? See https://raw.githack.com/GeoscienceAustralia/AusPIX-DGGS-ontology/master/auspix.html#AusPIXCell for an example. Note that this is implemented for AusPIX.

[nicholascar]

@dr-shorthair

Where is the ontology used for the RDF encoding of this DGGS ontology documented? https://w3id.org/dggs/abstract/ont/ does not dereference.

Not available yet: It's being derived from the abstract DGGS spec and a collection of DGGS terms being assembled as part of OGC Testbed 16 DGGS activities. I'll publish it shortly alongside the completed TB16Pix reference grid dataset.

Were you aware of what we'd already done here

Of course, I see all the linked.data.gov.au PIDs! What I'm doing will be compatible with that, perhaps with a few more classes, SHACL validators etc. for testing. AusPix will likely fit in nicely as a profile of this generic DGGS ontology, based on the Abstract Specification.

One small difference is that initially in TB16 we are not so concerned with DGGS --> CRS so instead of worrying about:

auspix:R7852 a apo:Cell ;
    geox:hasCentroid 'POINT (149.4444 -35.2391)'^^geo:wktLiteral ;

We really only need DGGS geometries, so something like:

tb16pix:R232
    geo:hasGeometry [
        geox:asDGGS "<https://w3id.org/dggs/tb16pix> R232" ;
    ] ;

Yes, the geo:Feature tb16pix:R232 has a TB16 geo:Geometry of "R232", It has a WGS84 geometry too, but that's of secondary interest for the tests we are doing.

We will have:

• a generic DGGS ontology, based on the Abstract Spec, of which AusPix ont is a profile
• a TB16Pix reference dataset
• the AusPix dataset, likely compatibly modelled just like TB16Pix, but perhaps not stand-alone in the same way
• 2+ datasets using TB16Pix geometries
• a DGGS client (made by Byron) which will demo with the 2+ datasets
• a LD catalogue of all the DGGS parts (using CatPrez, of course)