Visualization Tools for Clustering, Trees and Ordered Trees

Consider the situation of a set of individuals visiting a library and browsing through a collection. Each individual will, of course, select different books to browse depending on the original purpose of the visit. In addition, the order in which they search through a catalog will differ. The order is often ignored, yet might provide interesting cues as to the importance of certain books or topics. This scenario is not limited to browsing physical collections, but rather is repeated almost continually in other information-seeking behaviors including searching of on-line databases and hypenext/hypermedia systems.