A chorem-based approach for visually analyzing spatial data

摘要

The need to support the activities of decision makers through highly interactive visual environments has motivated the growing interest in the area of GeoVisual Analytics. New interactive visualization tools are being envisaged to deal with large datasets in order to synthesize information and perform complex analytical tasks. Along this line, our research efforts have been focusing on new cartographic approaches which could support daily analysts' work by producing synthesis and presentation of discovered patterns in a concise and understandable way. As a result, we have proposed the adoption of chorems as an innovative method to visually summarize information from spatial databases and we have implemented an XML-based language, named ChorML, able to both specify chorems characterizing a map and store the information useful to their manipulation. The goal of the present paper is to enhance the role that chorems may play in geographic domains, by exploiting them also for querying and accessing data associated with a phenomenon under investigation. To develop this idea, we first extend the semantics associated with the chorem concept and define a set of operators useful for the rapid analysis of spatio-temporal phenomena. Then, starting from an initial prototype, we present a chorem-based visual environment that integrates traditional interactive visualization and analysis techniques. The environment is specifically conceived so that each visual interaction task has a context-sensitive behavior, which allows users to acquire specific information from the underlying spatial database. Finally, we present an enhanced version of ChorML language, able to support the new analysis functionalities on chorems.