The sketch recognition and query interpretation by GSQL, a geographical sketch query language

Geographic information is intrinsically spatial and it can be conveniently represented using a bi-dimensional space. Graphical user interfaces and visual languages can be used to satisfy this need. However the growing availability of sketching enables the users to have a more informal and natural approach in the interaction. For this reason this paper presents GSQL (geographical sketch query language), a sketch-based approach for querying geographical databases. Each one of the users can easily sketch his/her geographical query by drawing it, erasing and modifying its parts and highlighting the query target. Context independent sketch interpretation uses spatial and temporal information related to the process of sketching, while context-dependent sketch interpretation uses geographical domain information to solve the remaining ambiguities and to provide the correct drawing and query interpretation. Also an analysis of the ambiguities, which characterise sketching of objects in the geographic application domain, and their possible solutions are presented