There are two main approaches to subject classification currently being explored for future use in DITA, which this page will call the map-based approach and the metadata approach.
In the map-based approach, a taxonomy is represented using a hierarchy in a DITA map. Each member of the hierarchy is a specialization of the <topicref> element. Each <topicref> element points to a topic that describes the subject of that node of the taxonomy.
A plug-in for the DITA toolkit that enables a taxonomy specialization is available for download at sourceforge.net. Although the plug-in is somewhat experimental, it is being used, and merits mention here.
The URL to access the plug-in is:
Here are some simple notes on how to retrieve and install the plug-in.
A natural complement to topic orientation, in which topics are made independent of one another, are various organizing methods for topics.
The DITA map offers authors several ways to organize topics, but users who encounter a DITA map may not wish to access their topics the way the author of the DITA map expected.