Dynamic 3D visualization of database-defined tree structures on the WWW by using rewriting systems

This paper presents a new Web-based technique for visualizing dynamically large hierarchies, tree or category structures in 3D worlds. The technique uses CGI-scripting, SQL queries and applet-based production systems to visualize in an efficient and versatile manner general category structures that are stored in relational databases. First, appropriate SQL queries extract the hierarchical category or tree structure from the database. Then, the minimal information is transmitted over the net to the user's applet that generates a production system according to an optional visualization model. The interactive applet builds the corresponding 3D world and visualizes the category structure. As a test-bed for our Web-based visualization technique we use a commercial e-commerce framework and extended it with the corresponding features. We illustrate our technique by visualizing the complete mall structure according to different visualization models, such as axial trees, cone trees and enclosure models, for instance.