Geonames ontology v2.0 review 2/3
Geonames Core ontology
The geonames ontology is merged with SKOS (Simple Knowledge Organisation Systems). SKOS facilitates the building of thesauri, taxonomies and controlled vocabularies in a simpler way than OWL. This characteristic is used by geonames ontology to define a geographical feature types taxonomy.
The ontology:class class (be careful with the name) is inherited from SKOS core:ConceptScheme class in order to define feature schemes. Nine instances of ontology:class have been defined:
ontology:A country, state, region
ontology:H (water bodies)
ontology:L (parks, areas)
ontology:P city, village
ontology:R road, railroad
ontology:S spot, buildings, farms,
ontology:T mountain, hill, rock
ontology:U undersea
ontology:V forest, heath
For each feature scheme there exists a set of concepts, which are instances of ontology:code.The ontology:code class is inherited from SKOS class core:Concept. In SKOS, the core:Concept class provides the instances of Concepts for each ConceptScheme. So the ontology:code provides the instances of feature schemes. For example, a S.BLDG ontology:code instance represents a building (a structure built for permanent use, as a house, factory, etc).
As we can see in the feature codes list, just physical types of geographical features are used. Other concepts related with geographical places are not defined (for instance, “shopping”, or “Comedia Show”).
The ontology:Feature class is related to the feature scheme via the properties ontology:featureSchema and ontology:featureCode. There is an special isolated feature type, ontology:Country, which has a proper treatment. Perhaps the ontology:Contry class and the ontology:inCountry property make it easy to set the geographical wide scope. But this concept should be also defined as an instance of core:Concept. This duplicated definitions are not very understable in an ontology engineering sense.
The Geonames Ontology allows three kind of topological properties between properties, ontology:nearby, ontology:neighbour and ontology:parentFeature. This can provide nice reasoning capabilities.Besides it defines an uncertain concept, ontology:nearby, opposite to classical GIS crisp relationships.
