Scope

Scope is the term used in the topic map standard to refer to a constraint or a context in which something is said about a topic. The way in which such statements about topics are made is by adding a name to the topic; specifying an occurrence for a topic; or creating an association between topics (in which case the statement applies to all of the topics in the association).

In many cases statements are not always true, but are dependent upon a context. For example we make statements such as "ABC Limited was top vendor of widgets in Q2 2004," or "Fred says that ABC Limited is a good investment." In these statements the context is shown in italics - a temporal context in the first case and a quotation context in the second case. More prosaically, context is often used to facilitate multi-lingual interfaces, so the concept "Dog" may have the label "dog" in the context of the English language, "le chien" in French, and "das Hund" in German.

In a topic map, scope is defined by a collection of topics that can be assigned to a name, an occurrence, or an association. The default scope (where no set is assigned) is known as the unconstrained scope and simply means that the name, occurrence, or association is always valid.

When a topic map-aware application encounters a name, occurrence, or association that has a scope assigned to it, the application should make use of information it has about the current operating context and compare that information against the scope information contained in the topic map to determine if the construct is valid and whether or not it should be presented to the user.