=Paper=
{{Paper
|id=None
|storemode=property
|title=Advanced Ontology Visualization with OWLGrEd
|pdfUrl=https://ceur-ws.org/Vol-796/owled2011_submission_7.pdf
|volume=Vol-796
|dblpUrl=https://dblp.org/rec/conf/owled/BarzdinsCLS11
}}
==Advanced Ontology Visualization with OWLGrEd==
https://ceur-ws.org/Vol-796/owled2011_submission_7.pdf
Advanced ontology visualization with OWLGrEd
Jānis Bārzdiņš, Kārlis Čerāns, Renārs Liepiņš, Artūrs Sproģis
Institute of Mathematics and Computer Science, University of Latvia,
Raina blvd. 29, LV-1459, Riga, Latvia
Janis.Barzdins@lumii.lv, Karlis.Cerans@lumii.lv,
Renars.Liepins@lumii.lv, Arturs.Sprogis@lumii.lv
Abstract. Intuitive ontology visualization is a key for their learning, exchange,
as well as their usage in conceptual modeling. OWLGrEd is a visual tool for
compact graphical UML-style rendering and editing of OWL 2.0 ontologies.
Here we introduce into OWLGrEd visualization annotations that allow defining
custom visual presentations of ontology entities on the basis of annotations
attached to these entities. The introduced mechanism of attaching visual
annotations to annotation properties used in the ontology, besides being
convenient for attaching graphical shape to user-defined annotations, appears to
be powerful enough to cover visualization of e.g. UML stereotypes and other
UML constructs that do not have direct counterpart in the "logic" part of OWL.
Keywords: OWL ontologies, visualization, annotations, OWLGrEd.
1 Introduction
Intuitive ontology visualization is a key for their learning, exchange, as well as their
usage in conceptual modeling. There are a number of tools (e.g. [1,2,3,4]) for rende-
ring and/or editing OWL ontologies in a graphical form. ODM [1] and OWLGrEd [4]
are oriented on visualization of OWL ontologies in the style of UML [5] class
diagrams. The main idea of OWLGrEd has been to provide compact graphical
notation for OWL ontologies, by combining the graphical visualization facilities of
UML class diagrams with textual facilities of OWL Manchester encoding [6].
Although OWLGrEd can be successfully used for ontology presentation and
editing in a UML-style graphical form (cf. [7]), the practical task of ontology-based
modeling suggests further facilities that would be welcome in a graphical ontology
editor. The ontology designer may attach certain specific meaning to some ontology
entities by user-defined annotation properties and then may wish to create specific
visualization patterns for the introduced properties. For instance, if an annotation
assertion relates an OWL class to a database table expression, a database icon besides
the table expression field may be appropriate in rendering this annotation assertion.
There are also natural modeling constructs in UML that do not have direct
counterpart in OWL, such as stereotypes, composition relation and derived union of
properties (or “abstract” property A, not having other subject-object pairs than those
of union of B and C). The visual annotation framework that we introduce in this paper
allows both visual effect specification for user-defined annotations and visual
modeling of the mentioned “advanced” UML concepts (these concepts may be said to
correspond to “user-defined” annotations from OWL perspective, as well).
In what follows, after brief reviewing of basic OWLGrEd ontology modeling
facilities we proceed to the main point of outlining the visual annotation framework
and some its usage examples, including advanced UML construct modeling.
2 Basic OWLGrEd constructs
OWLGrEd provides graphical notation for OWL, based on UML class diagrams. We
show OWL classes as UML classes, data properties as class attributes, object
properties as associations, individuals as objects, etc. We enrich the UML class
diagrams with the following new extension notations (cf. [4, 8]):
• fields in classes for equivalent class, superclass and disjoint class expressions
written in Manchester OWL syntax [6];
• fields in associations and attributes for equivalent, disjoint and super properties
and fields for property characteristics, e.g., functional, transitive, etc.;
• anonymous classes containing equivalent class expression but no name;
• connectors for visualizing disjoint, equivalent, etc. axioms;
• boxes with connectors for n-ary disjoint, equivalent, etc. axioms;
• connectors for visualizing object property restrictions some, only, exactly, etc.
OWLGrEd provides option to specify class expressions in compact textual form
rather than using separate graphical element for each logical item within class
expression. If an expression is referenced in multiple places, it can optionally be
shown as an anonymous class. An anonymous class is also used as a base for property
domain/range specification, if this domain/range is not a class.
Thing {owl} eats
eaten-by-animal
is-part-of eaten-by {>
Herbivore
Carnivore = Animal
eaten-by some [1..*]
Tree Tasty-plant = Animal and (eats only
and (eats some Animal) (Plant
is-part-of or (is-part-of only Plant)))
only <