Importing Ontologies in P41

Under Construction

Importing Ontologies in Protege 4.1

In this section, I will walk you through adding an import to an ontology. The purpose of this page is to illustrate OWL 2.0 imports and explain the design of the Protege 4.1 import mechanism. First I will introduce some terminology.

An import declaration is the owl statement that is used to import an ontology. Here is a simplification of the ontology declaration from the pizza ontology:

    <owl:Ontology rdf:about="http://www.co-ode.org/ontologies/pizza/2005/10/18/pizza.owl">
        <owl:imports rdf:resource="http://protege.stanford.edu/plugins/owl/protege"/>
    </owl:Ontology>

This declaration states that the pizza.owl ontology imports all the assertions found in the protege ontology. The OWL 2 specification has the following to say about the imported declaration (http://protege.stanford.edu/plugins/owl/protege in this case):

these IRIs identify the ontology documents of the directly imported ontologies as specified in Section 3.2.

And in section 3.2 we have the following expansion of this definition:

• Each ontology document can be accessed via an IRI by means of an appropriate protocol.
• Each ontology document can be converted in some well-defined way into an ontology (i.e., into an instance of the Ontology UML class from the structural specification).

While this description leaves much of the meaning of exactly what is done with an import declaration to the implementation, the reference to an appropriate protocol makes it fairly clear that we are talking about finding the ontology to be imported by chasing down an ontology location. So in the case of the pizza ontology, the protege import should be treated as a URL and the ontology to be imported is found using the http protocol.