Abstract. With the continuous growth of ontologies in size, the amount of ontology axioms is steadily increasing. To help users understand ontologies with a large number of axioms, we devise a novel ontology visualization tool,called AxiomVis, which defines a mapping from DL axioms to the directed acyclic graph (DAG). We give a recursive <br> procedure to generate the target DAG and then propose a new axiom-aware layout algorithm to display the DAG elements <br> using the characteristics of the expression tree. The distinguishing feature of our tool is that it visualizes ontologies from the axiom viewpoint. <br> This paper demonstrates comparison of different layouts, which exhibits the advantages of our layout on ontology visualization.

Keywords: ontology, axioms, visualization, layout