Towards topological consistency and similarity of multiresolution geographical maps
Several application contexts require the ability to use together and compare different geographic datasets (maps) concerning the same or overlapping areas. This is for example the case of mediator systems, integrating distinct data sources for query processing, and GISs dealing with multi-resolution maps. In both cases, distinct maps may represent the same geographic feature with different geometry type (a road can be a region in one map and a line in another one). An important issue is therefore determining whether two multi-resolution maps are consistent, i.e., they represent the same area without contradictions, and, if not, if they are at least similar. In this paper we consider consistency and similarity of multi-resolution maps with respect to topological information. Existing approaches do not take feature geometry type into account. In this paper, we extend them with two notions of topological consistency, the first requiring the same topological relation between pairs of common features, the second `relaxing' the first one by considering similarity between topological relations. A similarity function for multi-resolution maps is then provided, taking into account both feature geometry types and topological relations of map objects. We finally discuss how the proposed consistency and similarity concepts can be significantly used in GIS applications. Some experimental results are also reported to show the effectiveness of the proposed approach.