ABSTRACT
Conceptual graphs (CGs) were introduced by Sowa in 1984. They constitute a visual, advanced knowledge-based representation formalism grounded on philosophical, linguistic, and object-oriented principles (Sowa, 1984, 2000) and are considered the most general and exible logic notation that can be transformed to any form of logic (Sowa, 2004). One of the major advantages of CGs in relation to other knowledge representation approaches is that of being close to humans’ perception and reasoning. Initially, the purpose of CGs was to facilitate the transition from natural languages to structured logical forms and vice versa (Sowa, 2000), but in time they found use in many other elds, such as text mining (Cyre, 1997; Montes-y-Gómez, Gelbukh, and López-López, 2002; Hensman, 2004) and information retrieval (Huibers, Ounis, and Chevallet, 1996; Zhong et al., 2002). More recently, CGs have started to nd application in the geospatial domain, as will be shown in the next sections.
