Cigales, a Visual Query Language for a Geographical Information System: the User Interface
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Abstract In this paper we focus on the design and the implementation of a query language, Cigales (Cartographical Interface Generating an Adapted Language for Extensible Systems), for geographical information systems. This language is based on a visual and declarative query-by-example philosophy. The semantics of an end-user query is expressed by a drawing. We present the querying philosophy of the Cigales language. To take into account the particularities of the visual query language and the geographical data, we introduce several extensions to the classical database models (i.e. the icons, the variables, the overlap of the spatial representation). To illustrate the concepts of the Cigales language, we provide the representation of several queries (involving a unique 'object', two 'objects' without operators, two 'objects' linked with a spatial operator, several 'objects' linked with several spatial operators). Since the design of a user interface is an iterative process, the implementation is still going on and we present the current state of the Cigales prototype.