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Here's what I have (using a Mac):

  • An ontology was created in Protege (v5), incorporating some classes from established ontologies.
  • All classes were given the same Base URI.
  • HermiT, FacT++, Pellet, and Ontop plugin reasoners were used to test the ontology in Protege, and no errors or messages were returned.
  • Protege's Ontop plugin (v1.8) was used to map the classes to postgres RDBS column headers (table_column) and exported the R2RML mapping file.
  • The Ontop CLI was used to materialize triples through a jdbc postgres connection the ontology in turtle format, according to the R2RML .ttl mappings file.

Here's where my interactions with GraphDB (v8.2) start:

  • The GraphDB repository was created with an OWL2-RL profile with the 'read only' unchecked.
  • All ontology and materialized data triples were uploaded to GraphDB through graphdb-import folder in turtle format. All options checked on upload, and the same Base URI was provided.
  • The Class Hierarchy diagram suggests that the imported triples are properly structured.
  • The Class Relationship circular network graph shows reasonable relationships between the largest 10 classes.
  • The Domain-Range graph shows a number of in-going and out-going connections to nodes/individuals with predicates.
  • SPARQL queries appear to return expected values.

Here's my problem: When I enter the Visual Graph, I don't see anything. When I search and select a value that should have nodes, all I see is the single node with a message "This node has no visible connections."

What does this mean and where can I start troubleshooting? Or is the Visual Graph buggy?

Eric
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  • Please post your ontology and materialized data triples. – Stanislav Kralin Aug 15 '17 at 18:23
  • Maybe [this](https://stackoverflow.com/a/45102058/7879193) (scroll down to the "UPDATE" section). – Stanislav Kralin Aug 18 '17 at 10:36
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    I reached out to GraphDB and I'm currently troubleshooting. Apparently this Visual Graph feature filters out all rdf and owl classes to represent just part of the graph. In my situation, I used object properties in creating subclasses ('a class' and ('an objectProperty' some 'xsd:string')), and this doesn't explicitly create Domain-Range relationships with objectProperties. So I had no explicit relations, which could account for the behavior I was seeing. – Eric Aug 19 '17 at 12:57

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