241
•
Ontology Language: OWL
2
is the ontology language used to formalize
the ontologies stored in the catalog;
•
Ontology access and management operations: operations
to access and
manage ontologies will be implemented from a generalization of the
OGC Catalog service interface specification to metadata manipulation;
•
Objects access and management operations: operations
to access and
manage objects (instances) will be implemented from a generalization of
the OGC Gazetteer service interface specification to data manipulation;
The framework hot-spots are:
•
Catalog access interface: the interface
to access the catalog services;
•
Ontology repository: the implementation of the ontology repository.
•
Query language: the query language used to query ontologies in the
ontology repository;
•
Reference ontology: the reference ontology,
specific to the catalog
application domain.
4.
OGOC USAGE SCENARIOS
In this section we describe three usage scenarios of OGOCs, using the
geographic application domain.
Scenario 1:
In
this scenario, we describe the use of the OGOC as a mediator for
federated geo-object sources. Consider a user who wants to know facts about
the city of “Rio de Janeiro”. The catalog is invoked through the
GetObject
operation using the place name as the geo-object identifier
in the user query
(passed as a parameter of
GetObject). The catalog will execute the query
against
its ontologies repository, locating all objects from the “city” type that
have “Rio de Janeiro” as place name. The answer may include objects from
distinct sources registered in the catalog. This is possible because the catalog
stores mappings linking equivalent geo-objects
from distinct sources, even if
they pertain to different classes.
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