Creating a New Ontology

In this section, you will learn how to create a new ontology document in SemanticWorks. You will open a blank document in SemanticWorks, select an ontology compliance level (OWL Lite), and save the document, while briefly exploring the SemanticWorks interface.

1.	Start SemanticWorks by clicking the SemanticWorks shortcut in the Quick Launch tray or via the Start \| All Programs menu item. SemanticWorks starts. The application window looks something like this.

Notice that there are three windows: (i) the Main Window; (ii) the Overview Window; and (iii) the Errors Window.

If the windows are not arranged as shown in the screenshot above, try arranging it in this way. Do this by dragging the title bar of the Overview Window and dropping it on the left-pointing arrow that appears in the Errors Window. The Errors Window itself should be located at the bottom of the application window (down-pointing arrow of outer circle arrows).

3.	Click the New icon in the toolbar (or File \| New or Ctrl+N) to open a blank document in SemanticWorks. The Main Window will now look like this.

Notice that there are five tabs at the top of the window and that the Classes tab is selected. These five tabs organize the ontology information in five categories, thus providing an overview of ontology information. We refer to this view as the Ontology Overview (also called Overview for short; it should not be confused with the Overview Window). Further, notice that a pane containing subsidiary categories for the selected Overview category (currently, the Classes category) is displayed below the main category. With the Classes tab selected, the subsidiary pane displays the instances and properties of the selected class.

The ontology you will create in this part of the tutorial will use features of the OWL Lite sublanguage. SemanticWorks checks ontologies according to the language level selected by the user, and also makes available constructors specific to the selected ontology language. It is therefore best to select the required language at the outset. To select the OWL Lite sublanguage, do the following:

1.	In the RDF/OWL Level combo box in the toolbar, click the arrowhead to display the dropdown list of options (screenshot below). (Alternatively, select RDF/OWL \| RDF/OWL Level to display a submenu of language levels.)

Notice that as soon as the specification level is selected, a syntax check is run on the document, and the message This ontology is well-formed is displayed in the Errors Window.

Note: You can change the RDF/OWL level at any time. The selected level is retained through changes of views (Text View and RDF/OWL View). When you reopen an ontology document, you should check that the desired language level is selected.

It is a good idea to save the ontology before continuing. Save the file using any name you like and with either the .rdf or .owl file extension. (The .rdf extension is allowed because OWL ontologies are themselves RDF documents; it is, in fact, more usual than the .owl extension.) We'll assume that the file you create in this part of the tutorial is called AltovaProducts.rdf.

Having done all of the above, you are now ready to declare namespaces for your ontology.