Nearness relations in environmental space
The notion of proximity is a fundamental component of any comprehensive ontology of space. This paper presents an experiment with human subjects concerning the vague spatial relation 'near' in environmental space. After the topic is introduced and relevant previous work surveyed, the experiment is described. Three approaches to experimental analysis are presented and discussed: nearness neighbourhoods as regions with broad boundaries, fuzzy nearness and distance measures, and four-valued logic. Issues discussed in further detail are the truth gap-truth glut hypotheses regarding the psychology of vague predicates, and formal properties of the three-valued nearness relation. The conclusion is drawn that formal theories can usefully underpin and be applied to reasoning with vague spatial notions, such as nearness.