Every topic map application will be governed by its own unique topic map schema and its own unique system of topic instances. In most applications, the schema will be used to represent all the types of concepts presented by the site and the types of relationships between those concepts and between the concepts and other resources. You may also have a set of predefined topics that are used for classification purposes (often referred to as a taxonomy) - some more complex applications may include several taxonomies.

The class NetworkedPlanet.TMCore.Utils.ApplicationOntology provides a fast and convenient means of accessing the key topics that are part of both the topic map schema and any taxonomies that govern your application. Most importantly, the ApplicationOntology class provides a string replacement method that can be used in conjunction with the TMRQL query language, allowing you to embed human-readable references to topics within TMRQL queries without the need to do an explicit query of the subject identifiers table.

Before you can use the ApplicationOntology object effectively, you must assign a subject identifier to the topics you wish to be accessible. A subject identifier is simply a unique URI identifier for a topic.