Managing Qualitative Spatial Information to Support Query-by-Sketch

In this paper, we propose an extension of existing geographic information systems to support querying-by-sketch. It makes use of a particular class of queries, called qualitative spatial configuration queries, to match sketch-maps against spatial datasets. After analyzing several approaches, we identify the development of a dedicated qualitative layer as the most suitable solution. To face the combinatorial explosion in the number of qualitative relations, we introduce three different strategies to systematically reduce the information to manage. We provide a prototypical implementation for one of them and present empirical results showing the gain in performances when applying the implemented reduction strategy over the case when no reduction is performed.