SVIQUEL: A Spatial Visual Query and Exploration Language

This paper represents the rst eeort to apply direct-manipulation (VIS) techniques to spatial data exploration providing mechanisms for visually querying as well as browsing spatial data and for reviewing the visual results for trend discovery. We present a visual query language (SVIQUEL) which allows us to specify the relative spatial position (both topology and direction) between objects using direct manipulation of spatial query lters, called S-sliders. The S-sliders for the selection of precise numeric ranges for query dimensions are complimented by Active-Picture-for-Querying (APIQ), a qualitative direct-manipulation query paradigm. SVIQUEL thus supports spatial browsing and spatial trend discovery with no particular query in mind. The tight coupling between the quantitative S-sliders and qualitative APIQ allows the users to work either qualitatively or quantitatively depending on his/her particular needs and freely switch between the two while working in a continuous data exploration mode.