|DITA authoring concepts / Introduction to DITA|
Content in DITA is authored in topics, rather than in larger documents or publications. A DITA topic must make sense in its own right. A topic is authored as a unit, not as part of a larger document.
DITA has a topic-based architecture, requiring a topic-based approach to document authoring. The term topic can be thought of as being short for topical information unit, or a topical unit of discourse.
A topic-based architecture opens up the opportunity for large scale content re-use. Topics are assembled from a single pool or repository into different deliverable documents. Topics can be used in different publications, provided the topic makes sense when read in different contexts.
A special DITA file called a map or ditamap is used to specify topics to be included in a deliverable document. The ditamap doesn't store much content; it mainly comprises of pointers to the topics that contain the content.
Not only does a topic-based architecture allow information to be re-used, it also makes translation and localisation more efficient because the same information never has to be translated more than once.