Qualitative spatial reasoning about relative position the tradeoff between strong formal properties and successful reasoning about route graphs

Abstract

Qualitative knowledge about relative orientation can be expressed in form of ternary point relations. In this paper we present a calculus based on ternary relations. It utilises finer distinctions than previously published calculi. It permits differentiations which are useful in realistic application scenarios that cannot directly be dealt with in coarser calculi. There is a price to pay for the advanced options: useful mathematical results for coarser calculi do not hold for the new calculus. This tradeoff is demonstrated by a direct comparison of the new calculus with the flip-flop calculus.