A comparison of inferences about containers and surfaces in small-scale and large-scale spaces

Inference mechanisms about spatial relations constitute an important aspect of spatial reasoning as they allow users to derive unknown spatial informa tion from a set of known spatial relations. When formalized in the form of algebras, spatial-relation inferences represent a mathematically sound defi nition of the behavior of spatial relations, which can be used to specify c onstraints in spatial query languages. Current spatial query languages util ize spatial concepts that are derived primarily from geometric principles, which do not necessarily match with the concepts people use when they reaso n and communicate about spatial relations. This paper presents an alternati ve approach to spatial reasoning by starting with a small set of spatial op erators that are derived from concepts closely related to human cognition. This cognitive foundation comes from the behavior of image schemata, which are cognitive structures for organizing people's experiences and comprehens ion. From the operations and spatial relations of a small-scale space, a co ntainer-surface algebra is defined with nine basic spatial operators-inside , outside, on, off; their respective converse relations-contains, excludes, supports, separated-from, and the identity relation equal. The container-s urface algebra was applied to spaces with objects of different sizes and it s inferences were assessed through human-subject experiments. Discrepancies between the container-surface algebra and the human-subject testing appear for combinations of spatial relations that result in more than one possibl e inference depending on the relative size of objects. For configurations w ith small- and large-scale objects larger discrepancies were found because people use relations such as part of and at in lieu of in. Basic concepts s uch as containers and surfaces seem to be a promising approach to define an d derive inferences among spatial relations that are close to human reasoni ng (C) 2000 Academic Press.