This paper introduces a visual query system for geographical information systems, which is easy to use for non-professional persons. The system creates a new iconic metaphor — a card, which has a very strong expressive power and can be used to represent complex spatial objects and spatial relationships between objects. The end users can describe their query requirements in a visual programming environment by selecting appropriate cards and putting them into the proper query boxes. The result of the query is also displayed in graphical form, and this allows the user to understand the information easily.
Shiguang Ju, Weigang Guo, Héctor J. Hern&aa