Logical Consistency for Vague Spatiotemporal Objects and Relations

Vagueness is often considered as an inherent property of spatiotemporal phenomena. In order to reduce this vagueness, integrity constraints should be defined to improve logical consistency of spatiotemporal databases. However, existing constraints are not adapted to control logical consistency of vague spatiotemporal objects because they are initially defined for crisp (or non–fuzzy) objects. When applied to vague spatiotemporal objects or relations, such constraints would reject a large amount of data because they don’t authorize partial consistency in the database. In this paper, we present an approach to define integrity constraints which would be able to take into account spatiotemporal vagueness. We define three categories of constraints semantic, temporal and spatial accordingly to the nature of vagueness specific to each one. Then, we explain how these constraints could permit partial consistency of vague spatiotemporal objects and relations by using fuzzy logic.