University of Oxford

David M. Shotton

Graffoo*,* a Graphical Framework for OWL Ontologies \[1\], is a
wonderful new open source tool developed by Silvio Peroni that can be
used to present the classes, properties and restrictions within OWL
ontologies, or sub-sections of them, as clear and easy-to-understand
diagrams. Several Graffoo diagrams have been developed to explain SPAR
ontologies, or portions of them, and are to be found in the appropriate
ontology directories at
[[https://sempublishing.svn.sourceforge.net/svnroot/sempublishing/]{style="font-family: Times New Roman;font-size: 12pt"}](https://sempublishing.svn.sourceforge.net/svnroot/sempublishing/).

For example, in Figure 1 the diagram,
[[BiRO.png]{style="font-family: Times New Roman;font-size: 12pt"}](https://sempublishing.svn.sourceforge.net/svnroot/sempublishing/BiRO/BiRO.png),
illustrates the structure of [[BiRO, the Bibliographic Reference
Ontology]{style="font-family: Times New Roman;font-size: 12pt"}](http://purl.org/spar/biro/):

![](http://opencitations.files.wordpress.com/2011/06/062911_1339_graffooagra1.png){decoding="async"}[  
]{style="font-family: Arial;font-size: 11pt"}

[Graffoo diagram of BiRO, the Bibliographic Reference
Ontology]{style="font-family: Arial;font-size: 11pt"}

The upper part of this diagram shows how a bibliographic record, which
in [[FRBR
terminology]{style="font-family: Times New Roman;font-size: 12pt"}](http://www.rda-jsc.org/docs/mb-frbr-200804.pdf)
is a Work, (a) is a set of components (author names, publication year,
title, volume number, ISSN, publisher, dates of submission, acceptance
and publication, etc.), (b) references a published entity (a FRBR
Endeavor), and (c) can form part of a bibliographic collection such as a
library catalogue, which is also a set of components, in this case of
bibliographic records.

The lower part of the diagram shows how such a bibliographic record can
be realized (i.e. expressed in a specific form, forming what in FRBR
terminology is an Expression) as a bibliographic reference, such as you
might find in an article's reference list. The bibliographic reference,
while referencing the same published entity, differs from a
bibliographic record in two important ways.

- First, a bibliographic reference typically does not include all the
  components of the full bibliographic record. References typically
  exclude the ISSN, the name of the publisher, and the submission and
  acceptance dates; may exclude the publication date and some of the
  authors' names if there are many authors; and in certain journal (e.g.
  *Nature*) also exclude the title.
- Second, the components of a bibliographic reference form an ordered
  list rather than a set, although the precise order of components can
  vary from journal to journal (e.g. whether or not the publication year
  immediately follows the authors' names).

The diagram also shows that, just as bibliographic records may be
grouped into bibliographic collections, so bibliographic references may
be grouped into bibliographic lists such as reference lists (which, of
course, are themselves ordered lists), nicely exposing the symmetry
within the BiRO ontology in a manner that would be hard to grasp simply
by looking at the class structure within an ontology editor such as
[[Protégé]{style="font-family: Times New Roman;font-size: 12pt"}](http://protege.stanford.edu/).

The advantages of using such a Grafoo diagram are thus that it displays
the logical relationships between elements of an ontology, or a
sub-section of an ontology, in a manner that is relatively
straightforward to understand, once one has grasped the meaning of the
different elements of a Graffoo diagram. These elements are shown and
defined in the Graffoo key (Figure 2).

![](http://opencitations.files.wordpress.com/2011/06/062911_1339_graffooagra2.png){decoding="async"}

[Figure 2: The legend for all possible Graffoo objects  
]{style="font-family: Arial"}

From our preliminary empirical studies, it appears that Graffoo allows
us to create representations of OWL ontologies that can be comprehended
in detail without the person viewing them having to understand the
details of [[OWL
2]{style="font-family: Times New Roman;font-size: 12pt"}](http://www.w3.org/TR/owl2-overview/)
or of any of its linearizations
([[Turtle]{style="font-family: Times New Roman;font-size: 12pt"}](http://www.dajobe.org/2004/01/turtle/),
[[RDF/XML]{style="font-family: Times New Roman;font-size: 12pt"}](http://www.w3.org/TR/rdf-syntax-grammar/),
[[Manchester
Syntax]{style="font-family: Times New Roman;font-size: 12pt"}](http://www.w3.org/TR/owl2-manchester-syntax/),
or
[[OWL/XML]{style="font-family: Times New Roman;font-size: 12pt"}](http://www.w3.org/TR/owl-xmlsyntax/)).

Graffoo has been developed using the standard library of the [[*yEd*
diagram
editor]{style="font-family: Times New Roman;font-size: 12pt"}](http://www.yworks.com/en/products_yed_about.html),
a free diagram editor running on Windows, Mac and Linux. The
[[*graphml*]{style="font-family: Times New Roman;font-size: 12pt"}](http://graphml.graphdrawing.org/)
format version of those Graffoo objects is also available
[[here]{style="font-family: Times New Roman;font-size: 12pt"}](http://www.essepuntato.it/graffoo/sources).
We commend the use of Graffoo to other ontologists.

\[1\] Graffoo, the Graphic framework for OWL ontologies.
<http://www.essepuntato.it/graffoo>.


Graffoo
<em>
 ,
</em>
a Graphical Framework for OWL Ontologies [1], is a wonderful new open source tool developed by Silvio Peroni that can be used to present the classes, properties and restrictions within OWL ontologies, or sub-sections of them, as clear and easy-to-understand diagrams.

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Graffoo, a Graphical Framework for OWL Ontologies