XTM

Topic Maps provide for the specification of a standard, interchangeable hypertext navigation layer above diverse electronic information sources.  Topic Maps enable us to create virtual information maps for the Web, our Intranets, or even print materials. We have long understood the idea of creating style sheets to control the formatting and layout of information.  Topic Maps introduces the concept of creating style sheets to control knowledge-based information access and navigation. 

Because the Topic Map standard is an ISO/IEC standard, the specification of topic maps in the standard are in the ISO language, SGML.  There is an SGML Document Type Definition (DTD) to define the tags that make up an ISO/IEC topic map.  The maps themselves can be tagged in SGML according to that DTD or in the XML subset of SGML.  As it turns out, XML has spawned a whole new family of standards that work with XML in a Web environment such as XSL, XSLT, XPointer, XPath, and XLink.  In addition, two schema languages, RDF and XSD are emerging as well.  So the specification of how to use topic maps in the XML environment is more complex than simply interchanging a well-formed XML topic map document.  Many things must be taken into consideration to assure that Topic Maps will "fit" with the new Web environment. The stated goal of the XML Topic Maps activity,  known as XTM is to engage in technical activities to facilitate the use of topic maps based on XML, including but not limited to application on the Web.

XTM was developed by TopicMaps.org during 2000.  XTM has been pulled back into ISO for formal inclusion within ISO 13250.