¹Technical University of Denmark, Lyngby, Denmark

Correspondence: J Larsen, Informatics and Mathematical Modelling, Technical University of Denmark, Building 30, Lyngby 2800, Denmark. E-mail: jla@imm.dtu.dk

Received June 2004; Accepted August 2005; Published online 14 December 2005.

Abstract

An ontology is a classification model for a given domain. In information retrieval, ontologies are used to perform broad searches. An ontology can be visualized as nodes and edges. Each node represents an element and each edge a relation between a parent and a child element. Working with an ontology becomes easier with a visual representation. An idea is to use the expressive power of 3D representation to provide visualization for the user. In this paper, we propose a new method for positioning the elements of the visualized concept lattice in the 3D world based on operations research (OR) methods. One method uses a discrete location model to create an initial solution and we propose heuristic methods to further improve the visual result. We evaluate the visual results according to our success criteria and the feedback from users. Running times of the heuristic indicate that an improved version should be feasible for on-line processing and what-if analysis of ontologies.