The development, understanding, and maintenance of shared, formal models of disciplinary knowledge (ontologies) is one of the most important challenges of ecoinformatics. Ontologies are the glue that holds heterogeneous data and applications together. It is of paramount importance that natural system scientists have access to ontologies in ways that do not require them to become computer scientists or learn awkward concepts. Unfortunately, the development and understanding of ontologies are far from easy with the current generation of tools. GrOWL is the Ecoinformatics Collaboratory's answer to the need of intuitive knowledge visualization and editing tools.

The GrOWL project aims to reconcile modern ontology languages with the philosophy of semantic networks and concept maps, by providing a set of graphical idioms that cover almost every knowledge modelling construct and presents a "knowledge space" to users in an intuitive graphical translation. GrOWL provides a graphical browser and an editor of OWL ontologies that can be used stand-alone or embedded in a web browser. While it is in alpha stage, it is already being used in a number of projects, including the Ecosystem Services Database and SEEK. This page introduces GrOWL and its rapidly expanding feature list. GrOWL is open source, written in Java, and it can be downloaded in the download section of this site.

GrOWL has been designed following a policy-based paradigm, which implies that it's easy to create applications with different "personalities" from the same code. This allows us to distribute GrOWL as a stand-alone browser, an editor, or an applet. Other possible applications are being designed. Here is an introduction to the two major "incarnations" of GrOWL as it stands today.

GrOWL assisting search in the Ecosystem Services Database

GrOWL is designed to make complex ontologies look intuitive and to allow users to browse knowledge with ease. For this reason, it incorporates a number of features that are not available in other graphical knowledge representation frameworks.

The layout of the GrOWL graph can be defined automatically or loaded from a separate style sheet. This allows users to experience a consistent "shape" for the knowledge map that fosters recognition and creates familiarity.

There is usually some distance between the ontology that "works" for data integration or annotation purposes and the one that a human user can recognize easily and "sing along". To enable the display of ontologies as true concept maps recognizable by non-technical users, GrOWL implements configurable filters that can transform the display by simplifying it, hiding concepts and relationships that have no descriptions associated, or perform more complex translations (see the feature list).

Concepts can be stored in ontologies with extensive annotations to provide documentation. GrOWL shows these annotation as tooltips, and supports complex HTML and links within them. As user have become familiar with the web search engines pioneered by Google and others, GrOWL will integrate a search engine that is capable of looking up concepts based on search strings that can be as simple and as sophisticated as Google's. The ontology annotation properties (concept names, labels, and extended descriptions) can be searched and results returned as new browser starting points.

The GrOWL browser can be used inside a web browser or as a stand-alone application. When used inside a browser, it supports Javascript interaction so that it can be used as a concept chooser with implementation-defined operations. We are also gearing up to provide the scientific worfklow environment Kepler with a GrOWL-based semantic explorer to semantically annotate data and operations.

See the feature list for a systematic list of GrOWL current and planned features.

Screenshot

GrOWL can be configured to run as a graphical editor of knowledge maps. Users define concepts and relationships by dragging and dropping icons on a graphical canvas. Like the browser, the editor can be used stand-alone or as an applet running into a browser window.

Existing OWL ontologies can be loaded in the editor and automatically laid out graphically so that no concepts overlap and relationship arrows are optimally located. After the user has defined a preferred layout, the positioning of concepts on the screen is saved in a separate style sheet, so that the visual image of the concept map is not lost and persists between invocations. Users can modify existing ontologies and save them as new ones along with the preferred graphical layout.

Complementing the graphical image, GrOWL provides search facilities and a tree display that allows locating concepts from a structured list. Large ontologies present no problems to the GrOWL user because of the easy navigational tools that allow to quickly locate a concept of interest.