The management of the ambiguities in a graphical query language for geographical information systems

Abstract

This paper describes the management of the ambiguities which appear while querying a Geographical Database with a graphical query language. The goal is to hide a syntactic query language from end-users who do not usually think in terms of algebraic query language. Queries addressed to a Geographical Information System are very often divided into two classes: the network management oriented queries and the thematic oriented queries. We briefly present a graphical query language for each class of query. We develop the merger of these two languages in order to attempt to specify a unique graphical query language for geographical databases. We point out the various ambiguities due to the merging phase. These ambiguities mainly derive from the semantics of the operators and from the different levels of manipulation (logical or geometrical). We present the solutions we adopted in the context of the CIGALES* project.