DITA markup

The two main units of authoring in DITA are topics and maps. Each can be extended into new structural types and domains through specialization.

1. DITA topics
   DITA topics are the basic units of DITA content. Each topic should be organized around a single subject. Topics may be of different types, such as task or reference, or may be generic, that is, without a specific type.
2. DITA maps
   Maps organize topics for output to a specific deliverable, including generating navigation files and links to related topics.
3. Metadata elements and common attributes
   The same metadata elements and many of the same attributes are available in both DITA topic types and DITA map types. The sharing of metadata elements allows the metadata assigned to a topic when it is created to be supplemented or overridden when the topic is included in a collection. The sharing of attributes allows processing behaviors, such as content reuse and conditional processing, to be implemented consistently across both maps and topics.