# IsaViz: A Visual Authoring Tool for RDF ## Introduction IsaViz is a visual environment for browsing and authoring RDF models represented as graphs. It features: a 2.5D user interface allowing smooth zooming and navigation in the graph creation and editing of graphs by drawing ellipses, boxes and arcs RDF/XML, Notation 3 and N-Triple import RDF/XML, Notation 3 and N-Triple export, but also SVG and PNG export Since version 2.0, IsaViz can render RDF graphs using GSS (Graph Stylesheets), a stylesheet language derived from CSS and SVG for styling RDF models represented as node-link diagrams. | IsaViz 2.0 with support for GSS (click to enlarge)

## News

IsaViz 2.0 released (2003-08-08)

This new relase supports the Last Call Working Draft specifications issued by the RDF Core Working Group including datatypes. It also supports GSS (Graph Stylesheets) an RDF-based style language for rendering RDF models. Other new features include enhanced navigation, better handling of namespace prefix bindings, and an import/export plug-in interface. See changes for a complete list of new features and improvements.

Problem with GraphViz 1.10.0 (2003-07-31)

The first release of GraphViz version 1.10.0 contains a bug that causes dot to produce incomplete SVG files, thus preventing IsaViz from importing RDF files. This problem has been corrected in subsequent releases, which can be downloaded from the graphviz.org site. Note: this problem only affects users who have installed GraphViz version 1.10.0.

Important Note (2003-03-07)

Several people have encountered difficulties importing local RDF files in IsaViz 1.2 (and might encounter the same problem if upgrading from 1.0 or 1.1 to 2.0): the model is not loaded, and the following error message is generated:

RDFErrorHandler.error: com.hp.hpl.jena.rdf.arp.MalformedURIException: No scheme found in URI.

The source of this error is a bad Defaut Base URI in your preferences (e.g. "online"). To correct this, select Edit/Preferences, and set the Default Base URI value to blank or to the well-formed URI of your choice.

## Screenshots

More screenshots are available.

## Download

Latest stable version: 2.0

Binary distribution (zip file, 9.89 Mb) | isaviz-bin-2_0.zip
Binary distribution (tarball, 9.84 Mb) | isaviz-bin-2_0.tar.gz
Source distribution (tarball, 10.3 Mb) | isaviz-src-2_0.tar.gz
Older versions

Development version: the latest source code is available through the W3C's public CVS repository.

### Other Required Libraries

You will also need to download graphviz/dot for your specific platform (version 1.8.9 or later is mandatory if you are installing IsaViz 2.0). Note: some instances of version 1.10.0 had a bug that produced incomplete SVG files, but it has been corrected in subsequent releases (newer versions can be obtained on the graphviz.org site).

Finally, as IsaViz is implemented in Java, it requires a JVM (Java Virtual Machine) 1.3.0 or later (1.4.0 or later strongly recommended - see Known problems) since the GUI makes extensive use of Java2D which featured poor performances in JVM 1.2.x. The latest JVM from Sun can be downloaded at http://java.sun.com/j2se/1.4/

### Plug-Ins

The Sesame plug-in makes it possible to read/write RDF data directly from/to a Sesame server. It can be downloaded freely from the Sesame Sourceforge Project page.

## Documentation

Installation instructions contain information on how to install and configure IsaViz, including requirements for additional software versions. You should read these as they contain important instructions regarding GraphViz/dot which is not included in the distribution.

A User Manual describing all features of IsaViz is also available, as well as a User Manual for Graph Stylesheets (GSS).

## Mailing List

If you want to make comments, bug reports or simply ask a question, use the following mailing list: www-isaviz@w3.org. To subscribe to the list, send an e-mail to www-isaviz-request@w3.org with subscribe in the subject header. See http://www.w3.org/Mail/Request for more details. An archive of messages sent to the list is available.

## Known Problems

- When using a JVM 1.3.x to run IsaViz, it may randomly freeze for no apparent reason. This problem seems to occur especially on slow systems (no matter the OS) and on all UNIX/Linux systems. It is somehow related to the Java2D drawString method when combined with affine transformations (used by the ZVTM to draw text in the zoomable window). It seems to have been fixed in JVM 1.4.0, so I suggest that people encountering this problem run IsaViz using a JVM 1.4.0 or later (it should completely disappear).
- Due to a bug in GraphViz's SVG output, IsaViz is not able to fully load RDF models containing ampersand characters ('&') in literal values. The bug was reported against GraphViz version 1.7.6 and has been fixed in version 1.8.1 (it is still present in version 1.7.12). The corresponding error message looks like this: The parsing might not be complete (The file is probably not well-formed XML). Some nodes and edges might be missing from the graph because of an error (check error log) in file C:\Temp\isv20013.svg. You can get a more complete error report by reading the error log.
- The ZVTM uses a mouse cursor different from the system cursor, tightly coupled to ZVTM views and thus dependant on their refresh rate. It can therefore be difficult to control the mouse when browsing/editing big models. This difficult problem was addressed at the ZVTM level by implementing a specific XOR mode. This mode is available since version 0.8.0 of the library, which ships with IsaViz v1.1 and subsequent releases.

## Acknowledgements

IsaViz is developed by Emmanuel Pietriga.

The first version was developed in collaboration with Xerox Research Centre Europe which also contributed XVTM, the ancestor of ZVTM (Zoomable Visual Transformation Machine) upon which IsaViz is built. It also includes software developed by:

- HP Labs (Jena 2 Semantic Web Toolkit)
- The Apache Software Foundation (Xerces Java 2)

and makes use of the GraphViz library developed by AT&T Research.

The Sesame plug-in is developed by Aidministrator.

| Emmanuel Pietriga Last modified: Fri Aug 08 11:30:31 Eastern Daylight Time 2003