Topics

In this section we are going to learn about more specifically about topics, what they are, what a topic can contain and why we need different names for a topic. We also discuss the option of having occurrences and why it is useful, in some cases, to introduce classification. Finally, we will see how we denote a particular topic in XML. A step-by-step example will show you how to create this topic map. Now, when we start to collect some topics, the question comes up: What exactly is a topic?

It can be a person, an item, an organisation, a building, or a place. In our case we consider the following topics and write them in XML:

<topic id="bond-uni">
  :
  :
</topic>

<topic id="robina">
  :
  :
</topic>

<topic id="it-school">
  :
  :
</topic>

<topic id="faculty">
  :
  :
</topic>

We gave each of our topics an internal identification to allow to reference this topic somewhere else. What we also need is an external representation, a base name. This base name indicates how the topic should present itself to the end user. In most cases it will be similar to the internal identification, but this is not necessarily so:

<topic id="bond-uni">
  <baseName>
    <baseNameString>Bond University</baseNameString>
  </baseName>
  :
  :
</topic>

<topic id="robina">
  <baseName>
    <baseNameString>Robina</baseNameString>
  </baseName>
  :
  :
</topic>

<topic id="it-school">
  <baseName>
    <baseNameString>Bond School of Information Technology</baseNameString>
  </baseName>
  :
  :
</topic>

<topic id="faculty">
  <baseName>
    <baseNameString>faculty</baseNameString>
  </baseName>
  :
  :
</topic>

As you can see, in two cases the baseNames [ standard] differ from the internal identification.

Since for most of the topics there is also information on the web, it would be useful to add references to these webpages within a topic. This is done with so called occurrences:

<topic id="bond-uni">
  <baseName>
    <baseNameString>Bond University</baseNameString>
  </baseName>
  <occurrence>
    <resourceRef xlink:href="http://www.bond.edu.au/"/>
  </occurrence>
</topic>
  
<topic id="robina">
  <baseName>
    <baseNameString>Robina</baseNameString>
  </baseName>
  <occurrence>
    <resourceRef xlink:href="http://www.rcc.org.au/"/>
  </occurrence>
</topic>

You can have any number of occurrences [ standard] for a single topic, there is no limit, per se.

Sometimes it is also very useful to classify our topics by more general terms. A classification[ standard] of a topic references such a more general topic:

<topic id="bond-uni">
  <instanceOf><topicRef xlink:href="#university"/></instanceOf>
  <baseName>
    <baseNameString>Bond University</baseNameString>
  </baseName>
  <occurrence>
    <resourceRef xlink:href="http://www.bond.edu.au/"/>
  </occurrence>
</topic>

<topic id="robina">
  <instanceOf><topicRef xlink:href="#suburb"/></instanceOf>
  <baseName>
    <baseNameString>Robina</baseNameString>
  </baseName>
  <occurrence>
    <resourceRef xlink:href="http://www.rcc.org.au/"/>
  </occurrence>
</topic>

We have now introduced two references to new topics; university and suburb. These topics in turn have to be defined while - this time - we do not bother too much about occurrences or further classifications:

<topic id="university">
  <baseName>
    <baseNameString>university</baseNameString>
  </baseName>
</topic>

<topic id="suburb">
  <baseName>
    <baseNameString>suburb</baseNameString>
  </baseName>
</topic>

Both examples show the simplest way to define a topic. It is up to the author of the map to decide whether this process of classification should be continued for ever and ever and ever........

In a next step, we will start to create some associations.