ABSTRACT
This chapter establishes the basic principles of constructing a geographic ontology and has shown how these can be used to aid data integration. Ontologies can be characterized in different ways, in overlapping categories, such as top level, domain, application, micro-ontologies, and link ontologies. Organizations that supply general application-independent data, such as Merea Maps, are likely to produce domain ontologies. Application ontologies differ from domain ontologies as they include references to terms specific to a particular application or task. Top-level ontologies provide general vocabularies that can be utilized by domain and application ontologies. Micro-ontologies are a more recent attempt to develop authoritative and reusable ontologies. Use cases and competency questions are particularly useful for application ontologies that have specific uses. The glossary stage takes each term from the lexicon and develops an informal explanation expressed in natural language. Once the glossary is substantially defined it is possible to start to build the actual ontology by formally describing the classes and properties.
