Qualitative representations in large spatial databases

Qualitative representation of spatial information is important in large spatial databases. This type of information can be used in manipulation and analysis when no precise geometric information exist or are needed. Qualitative manipulation is particularly useful when integrating different geographic data sets, which may have been drawn from different sources at different times, which may have different accuracy measures, and which may vary in the scales of presentation resulting in possibly multiple representations of geographic entities. A representation scheme, denoted the Ring structure is proposed, where objects are grouped and ordered in layers based on adjacency and orientation. The method facilitates qualitative manipulation of the data and the efficient derivation of implicit information using spatial reasoning techniques. The method is shown to facilitate the integration of data sets by enhancing the process of spatial matching across these sets. The method is simple and can be used in many applications of large spatial databases, such as GIS, CAD and image databases