Editing OWL Ontologies

Altova SemanticWorks provides powerful support for creating and editing OWL ontologies in an intuitive, visual manner to implement Semantic Web applications.

OWL (Web Ontology Language) is an RDF-based language used to create Semantic Web ontologies. Ontologies indicate the hierarchies and relationships that exist between different resources within a specific domain. When RDF resource descriptions are associated with an ontology defined somewhere on the Web, intranet, or extranet, it’s possible for machines to retrieve the semantic information associated with each resource to find, present, and act on data in meaningful ways.

OWL has three sub languages, each with increasing complexity: OWL Lite, OWL DL, and OWL Full, and the choice of dialect depends on the complexity and level of detail required by your semantic model.

Altova SemanticWorks® 2009 supports all three OWL dialects in addition to full support for RDF and RDFS. Using SemanticWorks, you can create complex ontologies visually, using intelligent entry helpers, intuitive icons, time saving shortcuts, and many other features that make learning OWL easy. And, since SemanticWorks auto-generates the RDF/XML or N-triples code that corresponds to your design, building Semantic Web ontologies is as easy as plotting them out on a whiteboard.

Visual OWL Development

SemanticWorks® 2009 allows you to work with existing OWL documents or create new ones from scratch. Example OWL ontology files are shipped with the product, and the help file included with SemanticWorks contains an informative OWL tutorial to get you started learning OWL quickly and easily.

SemanticWorks® 2009 separates the different components that make up an ontology onto five tabs: Classes, Properties, Instances, allDifferent, and Ontologies. The classes tab lists all the classes available in the ontology with a separate window that lists the instances and properties of the selected class. All the properties of the ontology are listed on the Properties tab, and a separate window below the tab lists the domain of the currently selected property. All instances are listed on the next tab, and the allDifferent tab lists the items in the ontology that are mutually distinct. Lastly, the Ontologies tab lists all resources that are ontologies, including ontologies that have been imported into the current file. The details entry helper window provides a compact and editable description of any item selected in the Main Window. In an ontology, the Details Window is especially useful for creating and editing instances of a class.

SemanticWorks OWL editor

Each tab includes an insert button that allows you to add the corresponding type of ontology item with one click. Then, you can view and/or edit the details of any item by clicking its expand button. SemanticWorks displays resources graphically with informative icons for indicating item types, containers and collections (bag, sequence, etc.), class descriptions (unionOf, intersectionOf, etc.), class axioms (subClassOf, disjointWith, etc.), property descriptions (subPropertyOf, inverseOf, etc.), and more. When editing, you can insert these connectors using a context-sensitive right click menu or by selecting them from the SemanticWorks toolbar.

To help you immediately visualize relationships, OWL classes are encapsulated in yellow boxes with dashed lines surrounding sub-classes.

In addition to these informative visual indicators, holding your mouse over any item or icon listed in the display reveals its meaning or corresponding URI.

SemanticWorks OWL development

The SemanticWorks display is highly configurable, allowing you to adjust the width of the items in the graph, display it with a vertical or horizontal orientation, adjust the distances between parent and child nodes, change the font styles and colors used, and assign different colors to represent resources from different ontologies. You can even print the display of your OWL items to document the ontology.

To complement its intuitive visual design paradigm, SemanticWorks® 2009 provides numerous helpful features to speed ontology development, including:

An overview window for visualizing and navigating large ontologies
The ability to create instances of a particular class directly in the class detail view (without having to switch back to the instances tab)
Automatic assignment of mandatory properties when creating new instances of a particular class
Auto-generation of owl:allDifferent statements for multiple selected instances at once

defining owl alldifferent

SemanticWorks® 2009 provides full syntax checking to ensure that your OWL ontology properly conforms to the RDF/XML specifications. In addition, support for semantics checking in OWL DL and OWL Lite ontologies allows you to ensure consistency throughout your entire ontology definition. Any errors or conflicts are listed in the Errors window with a link to help you find and correct them quickly.

In addition to viewing and editing your ontology in the graphical RDF/OWL view, you can select the tab for the editable text view at any time to see how your document is being built in RDF/XML or N-triples, and you can export your document at any time to change from RDF/XML to N-triples or vice versa. Text view includes syntax coloring, source folding, and line numbers to help you understand and navigate the file easily.

OWL code