Geographic visual query languages and ambiguities treatment

The main issues of spatial databases and Geographic Information System (GIS), concern the representation, the management and the manipulation of a large and complex number of spatial objects and spatial relationships. In these systems many concepts are spatial and, therefore they are intrinsically related with a visual representation, which makes also easier to formulate queries by non-expert users. The main problems in visual query languages for spatial databases concern imprecision, spatial integrity and ambiguities in query formulation. Our concern in this chapter is with the ambiguity of visual geographical queries. In particular, a review of existing visual query languages for spatial databases and their classification on the grounds of the methodology adopted to resolve the ambiguity problem are provided.