Anatomy of a ditamap file

DITA maps files are primarily made up of topicref, topichead, topicgroup and topicmeta elements. DITA map files may also contain relationship tables, made up of rows and cells containing topicref elements.

The vocabulary of a ditamap file is quite simple. The principal element is the topic reference (topicref), which is simply a link to a topic to be included in the collection. The topicref elements can be nested, allowing you to build a hierarchy of links to topics.

Other elements which you can use to refine the hierarchy are:
an unlinked heading (or group) in the hierarchy
a way of grouping topicref elements together without affecting the hierarchy (used for applying characteristics to a group of topics at a time)
metadata for the topic that applies specifically to the context of the publication defined by the ditamap

As well as linking to topics, topicref elements can link to other ditamaps, thus permitting the embedding and re-use of ditamaps.

A ditamap file may also contain one or more relationship table (or reltable) sections. A reltable is made up of rows (relrow elements) of cells (relcell elements), usually with a header row (relheader elements). Cells contain topicref elements that link to topics. The relationship between topicref elements within rows and cells determines how generated links will appear in the output.