Expressive Power of a New Iconic Visual Query Language for Mobile GIS

S. Khaddaj and H.E. Elariss (UK)


Visual query language, mobile GIS, human-computer interaction, and usability testing


With the increase in the number of non-expert mobile users who query Geographic Information Systems (GIS), a new Iconic Visual Query Language (IVQL) has been designed and developed to allow users to easily formulate any combination of static, dynamic, simple and complex queries. Its query formulation has been illustrated using a sample GIS system for tourists and its evaluation carried out to test various aspects of usability such as the expressive power of the language, the query formulation, and the user interface (GUI). The evaluation of the expressive power that is hereby described has been implemented through both user testing and user satisfaction. The aspects that have been evaluated are the smiley icons, their level of recognition, and the expressive power of the visual query language. The results show that all the subjects were able to identify and recognize easily the majority of the icons without significant difference between the programmers and the non-programmers groups. Most of the subjects found that the icons have a good expressive power, a high level of recognition, and are easy to use. They also reported a high level of satisfaction with the aspects to the expressive power of the language.

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