Topics, Associations and Occurrences
A Topic represents anything we may think of, material or immaterial. It's just a string defining a subject. It holds no information by itself, but information will be linked to it. It's the basic building block of the topic map.For example, let's define a few topics about Astronomy; we will use them along this chapter to illustrate the various features offered by topic maps.
An Association is a way to link multiple Topics together – these topics are called the Association's members. For example, if we have a topic about Earth, and another about the Moon, we could create an association between these two topics, to show that the Moon is orbiting around the Earth (see graph below). What's more, each member of an association is assigned a role in this association. In our example, we see that the Earth gets the planet role in the association, while the Moon gets the moon role. The available roles are regular topics themselves, so you can create new roles when needed, name them whatever sounds meaningful to you, and use them afterwards in your new associations.
Note that a single Association can hold an infinite number of members, and a single topic can be a member of an infinite number of associations. In the graph below, for example, we can see that multiple planets are defined as belonging to the Solar System, using one single association.
Using these associations, you are going to create a whole network of topics, linked according to their respective meaning. And Goozzee will allow you to browse this network, jumping from topic to topic using these associations as some kind of path through your knowledge base.
Finally, Occurrences are where the real data resides. An Occurrence represents any kind of data : URLs of web pages, spreadsheet files, sound files, movies, texts, anything…
Occurrences are directly linked to Topics, without using any association or role. An occurrence is simply attached to a topic. A single Topic can contain an infinite number of occurrences, and a single occurrence can be linked to an infinite number of Topics.
In our example about Astronomy, we could link a video of the Apollo Mission to the Moon topic, or an URL to an encyclopedia entry about the Earth could be associated to the Earth topic... We could also import a map of the Solar System, and link it to all the planets of the Solar System.
So, to sum things up, associations are like paths that run though your knowledge base, jumping from topic to topic. And within the topics, you find occurrences (documents) related to the subject of each topic.