|DITA map files / Linking relationships|
The hierarchical relationship of topic references in the ditamap can be used to generate links from parent topics to child topics, from child topics to parent topics, and between child topics.
The hierarchy of topic references in the ditamap controls not only the sequence of topics in the output and/or the TOC, but also influences automatically-generated navigation links and generated summary content in parent topics in some output formats.
DITA permits you to adjust the basis on which the automatic navigation links are generated through the collection-type attribute of the topicref element.
Which collection type to use is dependent on the nature of the content. However, if in doubt, leave the default, which provides links to any child topics, and a link back from child to parent. This ensures that all topics in a hypertext output such as HTML can be traversed using links alone.