Current standards

ISO 13250-2: Topic Maps Data Model (TMDM)
The standard data model for Topic Maps, which defines the basic concepts of Topic Maps and their structure. This is the key Topic Maps standard.

ISO 13250-3: XTM 2.0
The current standard XML syntax for Topic Maps, defined in terms of the TMDM. This syntax is implemented by Ontopia and many other Topic Maps tools.

Other ISO standards
A site showing the status of the current work on the different ISO standards related to Topic Maps.

Historical standards

ISO/IEC 13250:2002 Topic Maps | pdf 217kb
The original Topic Maps standard was published in 1999. This is the updated edition from 2003, which includes the XTM 1.0 syntax.

XML Topic Maps (XTM) 1.0
The first XML syntax for Topic Maps, defined by TopicMaps.org in 2001, and later incorporated in the ISO standard. It has now been superseded by XTM 2.0.

Ontopia specifications

tolog – a tutorial | By Lars Marius Garshol
A tutorial introduction to the tolog topic map query language, which is implemented in the Ontopia, and which can also be used in the Omnigator.

Linear Topic Map Notation (LTM)
A compact textual syntax for writing Topic Maps, handy when authoring Topic Maps in a text editor.

RTM: An RDF-to-TM mapping vocabulary
An RDF vocabulary for describing RDF ontologies so that they can be converted into Topic Maps producing natural and directly usable results.

XTM Fragment Interchange
A specification of how to create a valid XTM document that contains all information about a single topic, in such a way that multiple fragments can be retrieved using, say, a web service, and correctly merged together.

Ontopia Schema Language (OSL)
A tutorial introducing the Ontopia Schema Language developed for Ontopia. It is now mostly of historical interest, and will be replaced by the ISO standard TMCL.

Canonical XTM
A proposal for a canonical XML-based format for Topic Maps suitable for use in test suites and so on. Now obsolete and replaced by the ISO standard CXTM.

The Ontopia XTM Comments | By Steve Pepper and Geir Ove Grønmo and Lars Marius Garshol and Kal Ahmed
Ontopia's comments on an early draft of the XTM 1.0 syntax. Made available here since it may be of historical interest.