Both ISO’s Topic Map Standards and the W3C’s Semantic Web Recommendations provide the means to construct meta-level semantic maps describing relationships between information resources. Developed independently, attempts at interoperability between the original Topic Map standard and RDF have proved challenging. However, ISO 13250’s drafting of an explicit Topic Map Data Model (TMDM) early in 2005, combined with the advent of the W3C’s more expressive Web Ontology Language (OWL) Recommendations in 2004, together now provide the possibility for authoring TMDM- conforming Topic Maps directly in OWL. OWL provides the ability to express the TMDM constraints explicitly and to ensure that Topic Maps authored in OWL conform to the TMDM.

This paper presents a construction of the TMDM model as an OWL-DL ontology. This “TMDM Ontology” is a construction in OWL of the Topic Map concepts modelled by the TMDM, making them available for use by Topic Map authors as a basis for building TMDM-compliant Topic Maps directly in OWL. Using OWL-DL as the language for Topic Map authoring gives users access to OWL’s formal semantics, constraint expressivity, and suite of tools such as Protégé, which includes an API and capability for ontology visualisation, querying, and automated constraint checking and reasoning using Description Logic reasoners. The approach described does not require the use of any Topic Map language, or Topic Map Constraint or Query language, although a simple algorithm could translate the OWL-authored Topic Maps directly into other TMDM-based Topic Map authoring languages if required, providing access to Topic Map engines and tools.

Illustrating by example, a Topic Map written in OWL-DL using Protégé is shown, highlighting the constraint and querying abilities provided, which overlap many of the requirements set by the ISO for a Topic Map Constraint Language and Query Language. One outstanding issue regarding the interpretation of Typing is identified, and options for its resolution are discussed.