The Ontology page shows the contents of the topic map based on its ontology. Each tab on the Ontology page displays a part of the ontology, based on the function of topics.
Since the ontology of a topic map is defined in terms of topics in the same map, the map can be used to described its own ontology. As you will see, in Kamala we use this powerful functionality and we call this the meta-ontology. It provides semantic structures and flexibility when we are adding new things in the map or we use it for navigation or querying.
If you are unfamiliar with terms such as topic types and Topic Maps ontology , we recommend to read this introduction first: The TAO of Topic Maps by Steve Pepper.
The following video explains the basics of topic types.
To capture semantic knowledge in a topic map, we give a type to the basic constructs of the topic map. A topic type represents the class of which the topic is an instance. A type is the collection of things of which you can say that there are instances of that category. Person is a type: someone is a person or isn't. If it does not have instances or it is difficult to find them, than maybe it does not have a type.
A topic type is thus a topic that has (or can have) instances. For example: Person, Organization, Project, City, Document. When viewed from the instance side, one can say "John is a Person", on the Ontology level one can easily add a new instance. This instance will get all the semantic knowledge of the person topic type in that map. Topic types play a key role within Kamala and provide a much used entry point into your topic map data.
If you create a new topic from the topic type list, it will automatically be typed as topic type. When you click on the name of a topic type in the list, you will be taken to the topic type's page that will show you the list of instances.
An association role type is a topic that is (or can be) used as the type of a role in an association. For instance the role type employer in the employment relation.
An association type is a topic that is (or can be) used as the type of an association, such as employment.
An occurrence type is a topic that is (or can be) used as the type of an occurrence, such as e-mail address or website.
April 2, 2013