Ontologies of geographic information

This article explores the notion of a system of ontologies specifically designed for the needs of an information science. A framework for geographic information ontologies is outlined that focuses on geographic information constructs rather than on the direct representation of real-world entities or on linguistic terms. The framework takes the form of a generative hierarchy anchored by the notion of intentionality at one end and of a spatiotemporal field of potentially relevant information at the other. Two theoretical notions are used in the generation of the hierarchy. The first is the principle of semantic contraction, whereby, starting from a level of geographic information constructs specified so as to reflect user intentionality, semantically coherent domains of properties are removed over several steps until only the rudiments of a spatiotemporal information system are left. The second notion is that of object of discourse, which allows entities to be represented as the composites of geographic information constructs at the higher levels of the hierarchy, explicitly reflecting the connections between the purpose, function, appropriate internal constitution, and ensuing categorization of the entities represented. The framework's main contribution is thus twofold: first, it allows the notions of user purpose and object function to be directly built into geographic representations; second, it proposes a hierarchy of ontological levels that are linked by systematic semantic relations. Further, the framework presents an integrated view of object and field representations. It may also provide a novel perspective on a number of issues of ongoing interest in geographic information science.