Ontology-based method for discovery of geographic information services

Finding suitable geographic information in the open and distributed OpenGIS Web Services (OWS) is a crucial task. The OpenGIS Catalogue Services provide searchable repositories of information descriptions, but these mechanisms to support the task of geographic information services discovery are still insufficient. Problems caused by semantic heterogeneity can arise during free-text search in catalogues. This paper introduces an ontology-based method for geographic information discovery that solved the semantic heterogeneity problems of current query capabilities. The approach combines ontology-based metadata with ontology-based search. There are three core parts playing an important part in the interpretation of the metadata and discovery of geographic information services: the ontology depository, the ontology reasoner and the user interface. We organize the ontologies in hybrid architecture that is good for the semantic translations. The reasoner is implemented by embedding the functions of the Description Logic system Racer, in which we can do the reasoning process easily. The implementation of the user interface is also a vital step; therein the requests and results should be interpreted in the light of the ontologies. By an example from the area of pollution of the environment our application shows that through inference executed by an ontology reasoner the request can be efficiently answered.