Reasoning about directions in an egocentric spatial reference frame

Within qualitative spatial reasoning, spatial objects having directions have been abstracted in different ways; directed line segments, oriented points etc. have been used. In certain applications, it becomes necessary to reason about directions of objects without focusing on the dimensionality of these objects. We present a framework for representation of and reasoning about directions in a qualitative way within an egocentric spatial reference frame. Qualitative direction has been separated from spatial location and dimensionality of spatial objects and as such, the formalism may be used to represent qualitative direction in a dimension-independent way. The formalism uses fewer numbers of base relations than existing formalisms. Further granularity can be refined easily. Qualitative direction relations separated from spatial location and dimensionality can be used to express spatio-temporal patterns of directional entities using a regular grammar. Keywords—QSR; Qualitative direction; Qualitative Direction Algebra; Composition.