Approximate queries by relaxing structural constraints in GIS

In the Geographic Information System (GIS) domain the evaluation of similarity among geographical objects plays an important role. This paper proposes an approach based on semantic and structural similarities to provide more flexible matches between the query search condition expressed by the user and the possible answers provided by the system. The relaxation model considers with different weights the semantic similarity of geographical concepts, that is evaluated by adopting the information content approach, and the structural similarity of the attributes and types of geographical objects that is inspired by the maximum weighted matching problem in bipartite graphs.The aim of the proposed methodology is to relax structural query constraints, in order to obtain meaningful answers for imprecise or missing data.