Query Formulation of a Visual Query Language for Mobile GIS

H.E. Elariss and S. Khaddaj (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 query formulation process that is hereby described has been implemented through both user testing and user satisfaction. Two subject groups, programmers and non programmers, undertook the tests. The results show that the visual queries are very easy to formulate using the IVQL. Subjects were able to answer correctly both simple and complex queries formulation questions with no significant difference in the performance of the two groups. In other words, the programmers performed in general as good as the non-programmers. This fact proves that IVQL is equally understood by people from different background and that there is no need to have any programming background or particular GIS query knowledge prior to using it.

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