[full paper] |

**Qualitative Spatial Reasoning about Line Segments**

*Reinhard Moratz, Jochen Renz, Diedrich Wolter*Representing and reasoning about orientation information is an important aspect of qualitative spatial reasoning. We present a novel approach for dealing with intrinsic orientation information by specifying qualitative relations between oriented line segments, the simplest possible spatial entities being extended and having an intrinsic direction. We identify a set of 24 atomic relations which form a relation algebra and for which we compute relational compositions based on their algebraic semantics. Reasoning over the full algebra turns out to be NP-hard. Potential applications of the calculus are motivated with a small example which shows the reasoning capabilities of the dipole calculus using constraint-based reasoning methods.

*Keywords:*Spatial Reasoning, Qualitative Reasoning, Constraint-Based Reasoning

*Citation:* Reinhard Moratz, Jochen Renz, Diedrich Wolter: Qualitative Spatial Reasoning about Line Segments. In W.Horn (ed.): ECAI2000, Proceedings of the 14th European Conference on Artificial Intelligence, IOS Press, Amsterdam, 2000, pp.234-238.

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