For subjects within the hasNarrower element, the container subject is more general than each of the contained subjects. That is, this element makes the default hierarchical relationship explicit, although the way in which a relationship is narrower is not specified.
See appendix for information about this element in OASIS document type shells.
- map/topicref subjectScheme/hasNarrower
This example specifies that Planting Roses is a narrower subject category than Horticulture, although it is part of the Horticulture subject area.
<subjectScheme> <hasNarrower> <subjectdef keys="horticulture" navtitle="Horticulture"> <subjectdef keys="plantrose" navtitle="Planting Roses"/> </subjectdef> </hasNarrower> </subjectScheme>
The following attributes are available on this element: Universal attribute group, Link relationship attribute group (with a narrowed definition of href, given below), processing-role from Attributes common to many map elements, navtitle from Topicref element attributes group, outputclass, keys, and keyref.
- A pointer to the resource represented by the topicref. See The href attribute for detailed information on supported values and processing implications. References to DITA content cannot be below the topic level: that is, you cannot reference individual elements inside a topic. References to content other than DITA topics should use the format attribute to identify the kind of resource being referenced.