In this demo paper we provide a brief overview of the main features of LODE, the Live OWL Documentation Environment. LODE is an online service that generates a human-readable description of any OWL ontology, taking into account both the ontological axioms and the annotations, and ordering these with the appearance and functionality of a W3C Recommendations web page, namely as an HTML page with embedded links for ease of browsing and navigation.
Understanding the aim and extent of an ontology is one of the most important
task of the Semantic Web. To this end, users usually start by consulting its
human-readable documentation. A large number of ontologies, especially those
used in the Linked Data world, have good comprehensive Web pages
describing their theoretical backgrounds and the features of their developed entities.
However, problems arise when we look at under-developed models, since
natural language documentation is usually only published once an ontology has
become stable. This approach is justifiable: writing proper documentation costs
effort, and re-writing it every time the developing ontology is modified is not
practical. For this reason, tools for the automatic online generation of HTML
documentation from ontologies – e.g. Parrot [
In this paper we introduce the main features of LODE, the Live OWL
Documentation Environment4 [
The rest of the paper is structured as follows. In Section 2 we present LODE, highlighting its main characteristics and features, and in Section 3, we conclude the paper by sketching out the future developments of our work. 2
LODE, theLive OWL Documentation Environment [
LODE automatically extracts classes, object properties, data properties, nam-ed individuals, annotation properties, meta-modelling (punning), general axioms, SWRL rules and namespace declarations from any OWL or OWL 2 ontology, and renders them as ordered lists, together with their textual and graphic definitions, in a single human-readable HTML page designed for easy browsing and navigation by means of embedded links. LODE can be invoked with a number of optional parameters so as to limit or extend the final documentation produced. For instance, it is possible to take into account all the entities in the ontology closure and/or the inferred axioms. The following pseudo-URL describes how to call LODE: rdfs:label) and then lists the metadata of the ontology, such as its IRI, authors (dc:creator annotations), date of publication (dc:date), and imported ontologies (owl:imports axioms). A brief abstract (rdfs:comment) and an automaticallybuilt Table of Content follow. When dc:description assertions are specified for the ontology, the section “Introduction” is created as the first item after the Table of Content. Then, LODE renders all the classes, object, data and annotation properties, named individuals, general axioms and SWRL rules, and concludes the document with a list of the namespaces defined in the ontology.
Displays information about imported ontology. All the annotations and axioms defined in the imported ontology are fully rendered in the documentation when one of the parameters “imported” or “closure” is specified.
Displays of axioms inferred by a reasoner. All the axioms inferable
by Pellet [
Axioms descriptions fully displayed. All the axioms and restrictions
are rendered within each entity definition through the Manchester Syntax [
Cool URIs to call the service. Any LODE URL built as shown in Fig. 1 is compliant with Tim Berners-Lee’s “Cool URI” definition7. This enables LODE to be used in conjunction with content-negotiation mechanisms, so as to produce HTML representations of ontologies and their entities automatically when accessing ontologies from a web browser.
Images can be included in the documentation. The annotation property dc:description can be used to refer to graphic files in addition to specifying simple text. In this case, LODE is able to render these graphic files as part of the documentation itself, as shown in Fig. 2a.
Permits choice of language in which to display the documentation. The text of the documentation can be rendered in a specific language when the parameter “lang” is specified. The selected language will be used as preferred language instead of English (the default) to render the documentation, as shown in Fig. 2b. Of course, this presupposes that appropriate language annotations are present in the ontology. 3
In this demo paper we briefly overview the main features of LODE, the
Live OWL Documentation Environment, our tool that automatically produces
HTML documentation of OWL ontologies. We recently performed two
different user evaluations so as to assess the usability of LODE when users use it
to deal with ontology understanding and navigation tasks. Preliminary results,
6 The screenshots shown in Figure 2 of this paper refers to the documentation
produced by LODE for the Argument Model Ontology (http://www.essepuntato.
it/2011/02/argumentmodel).
7 Cool URIs don’t change: http://www.w3.org/Provider/Style/URI.
presented in [