Towards an interaction level for object-oriented geographic database systems

Geographic database systems are large and complex systems characterized by a high degree of interactivity. Though the object-oriented approach is powerful enough for the representation of geographic information, the availability of a flexible and easy-to-use interaction level is essential for most users. In this paper, we focus on three major issues concerning any interaction level to be built on top of an object-oriented geographic database system, namely: spatial data modeling, user views, and browsing through spatial information. Despite what really is represented at the logical level, the spatial data model we refer to in this paper explicitly represents all kinds of spatial and non-spatial relationships of interest in the geographic context. This results in an effective conceptual tool for the definition of two different categories of views (namely, frame-based and map-based views). Both categories of views feature a high degree of flexibility; in fact, users are allowed to specialize the contents of a view according to their specific needs. A way of combining browsing and querying during the activity of exploring large spatial geographic databases through views is finally sketched in the paper.