A topic is a chunk of information organized around a single subject. Structurally, it is a title followed by text and images, optionally organized into sections. Topics can be of many different types, the most common being concepts, tasks, and reference.

Maps separate the context of your information deliverable from its content. In a typical HTML-based web site, any change to the appearance or navigation of the site typically means making updates to dozens or more individual HTML pages. DITA enables all the navigation (sequences, hierarchies, relationtions) to be managed from a DITA map, which allows authors to manage navigation from a single structure, and then generate new web pages as needed.

Maps let you organize topics that you want to build into an output web or PDF. You can also generate navigation files based on the map structure, and generate links that get added to the topics.

A map file references one or more DITA topic files using <topicref> elements. The <topicref> elements can be nested to reflect the desired hierarchical relationships of the topics. Map files need to have a file extension of .ditamap to be processed properly.

Read more

The basic concepts of DITA are not tied to implementation. Both schemas and DTDs can be used to define specializable DITA elements. The current DITA Open Toolkit provides both DTDs and XML Schemas.