TopBraid appears to enforce an assumption that the Ontology URI is the same BaseURI. This is not strictly required by the relevant standards, and may not followed by some published vocabularies, which (a) don't define a baseURI (in which case I think it defaults to the source URL or filename) (b) set the ontology URI to a different value to the Base URI.
Today I encountered this with the newly announced W3C Location vocabulary http://www.w3.org/ns/locn . After a lot of preliminary work, they have now moved the vocabulary into what is expected to be the permanent namespace http://www.w3.org/ns/locn# . So even though the vocabulary has not yet been finalized, it is now available for testing, and the intention is that this is the URI that it will be published at. I have tested the W3C deployment in TopBraid by creating a stub ontology that merely owl:imports from the web location. That goes fine. However, TopBraid does not allow me to open it directly. I retrieved the vocabulary and saved it as a file to a location from where I can access it within TB. When I attempt to open it I get the following error: "Can not open file locn.ttl. Reason: The file does not contain a valid base URI and cannot be opened. ..." Here are the relevant snippets from this vocabulary in TTL and RDF/XML formats: Turtle: @prefix locn: <http://www.w3.org/ns/locn#> . @prefix owl: <http://www.w3.org/2002/07/owl#> . @prefix vann: <http://purl.org/vocab/vann/> . @prefix voaf: <http://labs.mondeca.com/vocab/voaf#> . locn: a voaf:Vocabulary, owl:Ontology ; vann:preferredNamespacePrefix "locn"^^xsd:string ; vann:preferredNamespaceUri "http://www.w3.org/ns/locn#"^^xsd:anyURI . Right - no baseURI, so the base would default to the filename. But the Ontology URI is different, in fact the ontology URI is the same as the locn: namespace - i.e. it has a trailing #. Getting the RDF/XML version we find RDF/XML: <rdf:RDF xml:base="http://www.w3.org/ns/locn";> <owl:Ontology rdf:about="http://www.w3.org/ns/locn#";> <rdf:type rdf:resource="http://labs.mondeca.com/vocab/voaf#Vocabulary"; /> <vann:preferredNamespaceUri rdf:datatype="http://www.w3.org/2001/XMLSchema#anyURI";>http://www.w3.org/ns/locn#</vann:preferredNamespaceUri> <vann:preferredNamespacePrefix rdf:datatype="http://www.w3.org/2001/XMLSchema#string";>locn</vann:preferredNamespacePrefix> </owl:Ontology> </rdf:RDF> So in this case the baseURI is declared, but this is different to the Ontology URI. When I attempt to open this directly I get no error, but also no content visible in TBCME. Running experiment creating a new ontology via TBCME's File->New->RDF/OWL File dialogue, while it is possible to make the baseURI different to the filename, TB does not seem to allow the BaseURI and the Ontology URI to be different. Until now I had gone along with the TB assumption, but now we seem to have hit a wall. If I were to be engaging with a community that was not following the TB assumption, then I would not be able to use TBCME for ontology development. W3C is not just any community, so if this is the direction they are heading, then this could be a problem for TopBraid. And in this case I know the editors of this spec, and was invited to take part in the ontology development. I was unable to at this time, but would expect to engage more in the future. Simon -- -- You received this message because you are subscribed to the Google Group "TopBraid Suite Users", the topics of which include Enterprise Vocabulary Network (EVN), TopBraid Composer, TopBraid Live, TopBraid Insight, SPARQLMotion, SPARQL Web Pages and SPIN. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/topbraid-users?hl=en --- You received this message because you are subscribed to the Google Groups "TopBraid Suite Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
