A lot of people (myself included) find RDF (especially its RDF/XML representation) very verbose and not really for humans. At the same time, it happens (at least to me, but it bet it will be more and more common to you too in the near future) that you get an RDF model and you want to ‘take a look at it’.

It was Microsoft that introduced the “tree view” for an XML document in IE 5.0 as a way for people to ‘take a look’ at the XML documents that were starting to circulate. It seemed trivial but I found it to be more and more useful (so much that we cloned it in Cocoon for those browsers that didn’t support it).

The XML model is inherently a tree, so a tree view makes perfect sense as the maximum common denominator. But the RDF model is inherently a graph, way more complex than a tree and a ‘tree view’ of an RDF model feels much like looking at the shadow of an object to understand what it really is! A pain.

This is why Paolo and I wrote Welkin, the “IE XML tree view”-equivalent for RDF. And since we were at it, we added a few really nice features, like filtering by degree distribution of nodes, fisheye zooming, URI clustering and so on.

Welkin comes out of the work for Genius (that we presented at IDAMAP in 2004) drawing upon my Agora community visualization tool (that I very recently updated and now contains all the public ASF mailing lists, including the incubated ones! check it out!) and applying it to the visualization of gene networks. We understood that pretty much everything that was a graph exhibited similar properties and that by using RDF as the underlying model, we could create a very general tool, separating the concern of data production (and rdf-ization) from the data consumption (including exploration, visualization and analysis).

There is a lot of work still to do on Welkin, but I find it already very useful.

Enjoy.