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.

Visual Notation Interpretation and Ambiguities

This chapter introduces a classification of ambiguities in Visual Languages and discusses the ambiguities that occur in Spatial Visual Query Languages. It is adopted the definition of Visual Language, given in (Bottoni et al. 1995), as a set of Visual Sentence, each formed by an image, a description, an interpretation function and a materialization function. It is proposed a distinction between ambiguities produced by 1-n relationship between an image and its description, and ambiguities due to imprecision produced by the user’s behaviour during the interaction. Furthermore, the authors hope that this comprehensive classification of ambiguities may assist in the definition of Visual Languages, in order to allow the user to communicate through visual notations by avoiding to formulate sentences that have multiple interpretations.

Visual Query Languages, Representation Techniques, and Data Models

An easy, efficient, and effective way to retrieve stored data is obviously one of the key issues of any information system. In the last few years, considerable effort has been devoted to the definition of more intuitive, visual-based querying paradigms, attempting to offer a good trade-off between expressiveness and intuitiveness. In this chapter, we analyze the main characteristics of visual languages specifically designed for querying information systems, concentrating on conventional relational databases, but also considering information systems with a less rigid structure such as Web resources storing XML documents. We consider two fundamental aspects of visual query languages: the adopted visual representation technique and the underlying data model, possibly specialized to specific application contexts.

Visual query languages, representation techniques and data models

An easy; efficient and effective way to retrieve stored data is obviously one of the key issues of any information system. In the last few years considerable effort has been devoted to the definition of more intuitive; visual-based querying paradigms; attempting to offer a good trade-off between expressiveness and intuitiveness. In this chapter we analyze the main characteristics of visual languages specifically designed for querying information systems; concentrating on conventional relational databases but also considering information systems with a less rigid structure; such as Web resources storing XML documents. We consider two fundamental aspects of visual query languages: the adopted visual representation technique and the underlying data model; possibly specialized to specific application contexts.

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.