No abstract

No abstract

This paper presents a survey of query languages dedicated to Geographic Information Systems (GIS). Five categories of query languages can be identified : (1) natural languages, (2) extensions of SQL, (3) tabular languages : use of skeletons or forms, (4) graphical languages : use of symbols, which are only graphical conventions (like in the entity-relationship diagrams) and (5) visual languages : use of visual metaphors (e.g., icons, blackboard metaphor and map-overlay metaphor). The principles of each of them are presented. Respective strengths and weaknesses are pointed out, based on a set of predefined queries. The main objective of this paper is to present the state of the art of research work in a domain which is suitable for graphical querying. The last part of this paper describes hypermedia techniques.