A System for Querying With Qualitative Distances in Networks

A central role of Geographic Information Systems (GIS) is to allow the identification and visualisation of relevant spatial features from typically large volumes of data. This requires a querying system to provide both flexibility and usability. While standard GIS querying capabilities are often either very limited, or require a user to have knowledge in specialised areas, techniques in qualitative spatial reasoning have been developed that provide a powerful and intuitive method of representing and reasoning about spatial information. In this paper we present a method for querying about the qualitative distance between features using dynamic networks such as roads, bus or ferry services, and flight paths, rather than only using the Euclidean distance. Linguistic values are used to implement qualitative distances for the linguistic variable proximity. TreeSap GIS with qualitative querying support is presented to demonstrate how qualitative distance measures through a network can provide both a computationally practical solution and a mechanism through which non-experts benefit from powerful search tools.