Qualitative Spatial Reasoning about Oriented Points
Reinhard Moratz · 2004
Abstract We present a qualitative positional calculus which uses oriented points as basicentities. In contrast to often-used simple points, we consider objects that havean intrinsic direction. Having an intrinsic orientation is an important property ofnatural objects. 1 Introduction Qualitative Reasoning about space abstracts from the physical world and enables com-puters to make predictions about spatial relations, even when a precise quantitativeinformation is not available [2]. The two main trends in Qualitative Spatial Reason-ing are topological reasoning about regions [2, 9] and positional reasoning about pointcongurations [3, 11]. Especially positionalreasoningis importantfor robotnavigation[8].Back FrontLeftRight Figure 1: An oriented point and its qualitative spatial relative directionsIn the aforementioned approaches about orientations objects and locations are rep-resentedas simple, featureless points. In contrast, ourpaperpresents a positionalcalcu-lus whichuses morecomplexbasic entities. It is basedonobjects whicharerepresentedas oriented points. It is closely related to a previously designed calulus which is basedon straight line segments (dipoles) [7]. Conceptually our new calculus can be viewedas a transition from oriented line segements with concrete lenght to line segments with1