Current https://raw.githubusercontent.com/w3c/dxwg/gh-pages/dcat/rdf/dcat.ttl is inconsistent

[rduerr]

Using the ELK 0.4.3 reasoner on the dcat.ttl results in Error2 on:

'Catalog Record' SubClassOf foaf:primaryTopic only 'Catalogued resource'

I expect this is related to #771; but thought I should mention it anyway... Yes, we are trying to use DCAT 2 too early... Sorry about that...

[riccardoAlbertoni]

@rduerr wrote

Using the ELK 0.4.3 reasoner on the dcat.ttl results in Error2 on:

'Catalog Record' SubClassOf foaf:primaryTopic only 'Catalogued resource'

I expect this is related to #771; but thought I should mention it anyway... Yes, we are trying to use DCAT 2 too early... Sorry about that...

Thanks, @rduerr for warning us.
any other detail on the kind of environment you are using might be useful.
For instance, are you using ELK standalone or as a plugin of some Ontology editor?

[rduerr]

From within the latest version of desktop Protege

[riccardoAlbertoni]

Opening DCAT with protege5.0 returns the message
"Entity not properly recognized, missing triples in input?"
in correspondence of the unqualified cardinality restriction

dcat:CatalogRecord  rdfs:subClassOf [
        rdf:type owl:Restriction ;
       owl:cardinality "1"^^xsd:nonNegativeInteger ;
       owl:onProperty foaf:primaryTopic ;
] ;

I have made different attempts to fix this, but with very limited success.
Just reporting some of the many attempts I made

Attempt A:
Simply Drop the restriction, which produces a ttl which can be opened by Protege without problem

Attempt B :
Replacing the unqualified cardinality restriction with qualified restriction, but it does seem to work ...

Attempt C1:
Rewrite the unqualified cardinality restriction after opening the ttl, and save it as TTL, Then reopen it, obtaining the same error when reopening the created file.

Attempt C2:
Rewrite the unqualified cardinality restriction after opening the ttl, and save it as OWl functional Syntax.
Then reopen it. This seems to work. Protege 5.5.0 opens the ontology without ERROR.
I have to check consistency for the above with stand-alone ELK 0.4.3 reasoner, and everything seems to be ok.

I do not know what to think. Is it something connected to the serialization syntax? Any idea?

[dr-shorthair]

@cmungall have you seen this before?

[riccardoAlbertoni]

Following the discussion on PR 1003, I have made a further attempt:
Attempt D: Deleting all the multiline literals between """, but It does not resolve the issue.

[dr-shorthair]

The SWEET team have just uncovered a bug in OWLAPI which is currently preventing SWEET loading in Protege. It appears that there are issues with the latest OWLAPI - so it might not be a DCAT problem at all.
https://github.com/ESIPFed/sweet/blob/master/CONTRIBUTING.md#avoiding-presence-of-httporgsemanticwebowlapierrorerrorn-in-contributions-when-editing-using-protege

[cmungall]

Is there a ticket on the owlapi issue tracker?

[cmungall]

I just tried parsing https://raw.githubusercontent.com/w3c/dxwg/gh-pages/dcat/rdf/dcat.ttl

Missing semicolon on line 797 - is this hand-authored?

  skos:scopeNote "La descrizione dell'endpoint fornisce dettagli specifici dell'istanza dell'endpoint reale, mentre dct:conformsTo viene utilizzato per indicare lo standard o le specifiche implementate dall'endpoint."@it
  skos:scopeNote "La descripción del endpoint brinda detalles específicos de la instancia del endpoint, mientras que dct:conformsTo se usa para indicar el estándar general o especificación que implementa el endpoint."@es ;

[cmungall]

I think you need to declare primaryTopic to be an OP

This works as expected:

@prefix dcat: <http://www.w3.org/ns/dcat#> .
@prefix dct: <http://purl.org/dc/terms/> .
@prefix dctype: <http://purl.org/dc/dcmitype/> .
@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix locn: <http://www.w3.org/ns/locn#> .
@prefix odrl: <http://www.w3.org/ns/odrl/2/> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix prov: <http://www.w3.org/ns/prov#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix sdo: <http://schema.org/> .
@prefix skos: <http://www.w3.org/2004/02/skos/core#> .
@prefix time: <http://www.w3.org/2006/time#> .
@prefix vcard: <http://www.w3.org/2006/vcard/ns#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

foaf:primaryTopic a owl:ObjectProperty .

dcat:CatalogRecord  rdfs:subClassOf [
        rdf:type owl:Restriction ;
       owl:cardinality "1"^^xsd:nonNegativeInteger ;
       owl:onProperty foaf:primaryTopic ;
    ] .

however, omitting the declaration causes the parse error.

I believe this is consistent with the specs:

https://www.w3.org/TR/owl2-mapping-to-rdf/

Sometimes the owlapi will infer these declarations but this isn't guaranteed. Missing OP declarations is a common source of errors, especially when trying to repurpose ontologies that were designed to be RDFS as OWL ontologies.

[dr-shorthair]

Thanks @cmungall
I had a sneaking suspicion that FOAF could be causing the issue.
Good intel - I hope I remember it in future!

I think I've fixed it (and the missing ;) in https://github.com/w3c/dxwg/tree/dcat-issue-944