hydrOntology (Vilches-Blázquez et al., 2009) is an ontology in OWL that follows a top-down development approach. Its main goal is to harmonize heterogeneous information sources coming from several cartographic agencies and other international resources.

Initially, this ontology was created as a local ontology that established mappings between different data sources (feature catalogues, gazetteers, etc.) of the Spanish National Geographic Institute (IGN-E). Its purpose was to serve as a harmonization framework among Spanish cartographic producers. Later, the ontology has evolved into a global domain ontology and it attempts to cover most of the concepts of the hydrographical domain.

hydrOntology has been developed according to the ontology design principles proposed by (Gruber, 1995) and (Arpírez et al., 1998). Some of its most important characteristics are that the concept names (classes) are sufficiently explanatory and are correctly written. Thus each class tries to group only one concept and, therefore, classes in brackets and/or with links ("and", "or") are avoided. According to certain naming conventions, each class is written with a capital letter at the beginning of each word, while object and data properties are written with lower case letters.

Regarding methodological issues, the approach adopted is METHONTOLOGY, a widely-used ontology building methodology. This methodology emphasises the reuse of existing domain and upper-level ontologies and proposes using, for formalisation purposes, a set of intermediate representations that can be later transformed automatically into different formal languages. A detailed description of the methodology of this ontology building can be found in (Gómez-Pérez et al., 2003).

In order to develop this ontology following a top-down approach, different knowledge models (feature catalogues of the IGN-E, the Water Framework European Directive, the Alexandria Digital Library, the UNESCO Thesaurus, Getty Thesaurus, GeoNames, FACC codes, EuroGlobalMap, EuroRegionalMap, EuroGeonames, several Spanish Gazetteers and many others) have been consulted; additionally, some integration issues related to geographic information and several structuring criteria (Vilches-Blázquez et al., 2007) have been considered. The aim was to cover most of the existing GI sources and build an exhaustive global domain ontology. For this reason, the ontology contains more than one hundred and fifty (150) relevant concepts related to hydrography (e.g. river, reservoir, lake, channel, and others), 34 object properties, 66 data properties and 256 axioms.

Finally, the ontology documentation is exhaustive and, in this sense, definitions and their sources can be found in each concept (class). The ontology has an important amount of labels with alternative names (synonyms) as well as concept and synonyms provenances.

For downloading the ontology, use the following link.

References

• Arpírez JC, Gómez-Pérez A, Lozano A, Pinto HS (ONTO)2Agent: An ontology-based WWW broker to select ontologies. In: Gómez-Pérez A, Benjamins RV (eds) ECAI'98 Workshop on Applications of Ontologies and Problem-Solving Methods. Brighton, (UK), 1998, pp 16-24.
• Gómez-Pérez, A., Fernández-López, M., Corcho, O., 2003. Ontological Engineering. Springer-Verlag, London (United Kingdom).
• Gruber T.R. (1995) Toward principles for the design of ontologies used for knowledge sharing, International Journal of Human-Computer Studies, v.43 n.5-6.
• Vilches-Blázquez, L. M., Ramos, J. A., López-Pellicer, F. J., Corcho, O., Nogueras-Iso, J. (2009) An approach to comparing different ontologies in the context of hydrographical information. Popovich et al., (eds.): IF&GIS'09. LNG&C Springer. Pages: 193-207, St. Petersburg, Russia.
• Vilches-Blázquez L.M., Bernabé-Poveda M.A., Suárez-Figueroa M.C., Gómez-Pérez A., Rodríguez-Pascual A.F. "Towntology & hydrOntology: Relationship between Urban and Hydrographic Features in the Geographic Information Domain". In Ontologies for Urban Development. Studies in Computational Intelligence, Springer. 2007, vol.61, pp73-84