Cardinal relations between regions with a broad boundary
Serafino Cicerone, Paolino Di Felice · 2000
Despite the innovative relevance of the results about spatial relations today available, the expressiveness of spatial query languages needs to be pushed further significantly in order to cope with the complexity of spatial entities. In particular, more research is necessary in order to support queries against data with uncertainty. In connection with cardinal directions, the best method today available is the Boolean, 3 × 3 direction-relation matrix proposed very recently by Goyal and Egenhofer. Our paper extends such a method to the case of regions with a broad boundary by introducing a 4-value, 5 × 5 direction-relation matrix. Furthermore, the present contribution studies the notion of consistency for a direction-relation matrix and proposes a set of conditions which are necessary and sufficient for assessing consistency.