An intelligent and direct manipulation digitizing system

The Voronoi tessellation is of interest in the development of GIS methods for various reasons, especially as a form of topology. These reasons include Voronoi diagram dynamic maintenance and the idea of a “proximal query”, whereby an object may be specified merely by placing the cursor within its Voronoi region. This is a great advantage in the digitizing operation, because traditional systems need great care in general i ng t he topological relations. The Voronoi model merely requires the specification of each end point by pointing to its Voronoi “bubble”. Because the topology is maintained during the digitizing activity, ii truly interactive system is possible. unlike the usual “rebuild and then correct the errors” procedure. “Collisions” arc detected before they occur, and action taken, rather than awaiting a batch rebuild. This paper discusses the implications of this approach for the construction of a fast, efficient, interactive, user-friendly and “intelligent” (in the sense of help for geometric construction design and topological accuracy) digitizing system. Emphasis will be placed on the development of effective interaction with the user, and the minimization of digitizing time.