An approach to comparing different ontologies in the context of hydrographical information

Abstract

Geographical Information is increasingly captured, managed and updated by different cartographic agencies. This information presents different structures and variable levels of granularity and quality. In practice, such heterogeneity causes the building up of multiple sets of geodata with different underlying models and schemas that have different structure and semantics. Ontologies are a proposal widely used for solving heterogeneity and a way of achieving the data harmonization and integration that GIS and SDI need. This paper presents three hydrographical ontologies (which are built using top-down and bottom-up approaches) and an approach to comparing them; the goal of this approach is to prove which ontologies have a better coverage of the domain. In order to compare the resultant ontologies, six qualitative facets have been studied: sources used (amount, richness and consensus), reliability of building approaches (community extending use, recommendations), ontology richness (number and types of components), formalization (language), granularity (scale factor) and the design criteria followed.