Hierarchical Reasoning About Direction Relations

RS and GPS provide technical support for collection of spatial information, and GIS creates the theoretical and technical architecture of spatial information processing and application from the aspect of quantity. However, spatial information is complex. Considering quantity, spatial information is mass. The kinds of spatial information not only have numerical type, character type, but also have figure type and image type. The correlation between spatial information is inherent. So, quantitative research of spatial information is not enough, and qualitative research is necessary.Qualitative spatial reasoning that is generated by combining qualitative reasoning, spatial reasoning and artificial intelligence (AI) has been a hotspot in the research of AI. Different from the researches of structure, action, function and their interconnections of physical system in qualitative physics, qualitative spatial reasoning analyzes and processes the human cognition of geometric spatial common knowledge. Different from the researches of modeling, descriptions, representations, relations'analysis and processing of spatial objects in spatial reasoning researching, qualitative spatial reasoning faces to the qualitative characters and qualitative relations of spatial objects.Spatial objects researched in this paper are points, lines and areas in 2-dimensional space, and contents are direction relations representation and reasoning between spatial objects. And the reasoning researches hierarchical structure reasoning. Based on the profound analysis for representation and reasoning of direction relations, this paper proceeds with some originality innovation researches as follows:(1) Representation of spatial direction relationsThe theories about qualitative spatial reasoning and direction relations are introduced. The paper researches the basic representation models of direction relations (Cone Model, 2D-String Model, Projection-based Model). By analyzing the Projection-based Model D14, a new direction is put forward named GD8. D14 and GD8 can be considered as two levels of direction representation. The relation in D14 is more precise than that in GD8, but GD8 can represent direction relations which D14 couldn't.(2) Hierarchical spatial reasoningThe theories about hierarchy and hierarchical spatial reasoning are introduced. The paper researches Wayfinding based on hierarchical spatial reasoning particularly. The algorithm HWA has some disadvantages. The paper improves HWA and proposes...