Semantic Web, Zitgist, DataViewer

Zitgist’s RDF Browser: Browse the Semantic Web

I am pleased to announce the pre-release of the Zitgist RDF Browser. This new tool from Zitgist will help users to browse the information available on the Semantic Web. As you will see bellow, this tool is a sort of information shape-shifter. Depending on the data available for a given Thing (a resource), it will shapes its user interface so that the data is best displayed for a better understanding of its semantic and for a better browsing experience.

This pre-release version is usable by anybody, however I would appreciate that you report any bug, issues or suggestions to me so that I can enhance the browser to meet people’s expectations.

Introducing Zitgist’s RDF Browser


The Templating system

The core of this new RDF browser is its templating system. This system will enhance the RDF browsing experience of users along with their understand of the information displayed to them. People can see it as a typical web browser such as Internet Explorer or FireFox, but instead of reading and displaying HTML, it display RDF data. Users only have to put the URI of a resource (it can be a URL where the browser can find RDF information about this Thing), then pressing the “browse” button.

Then, depending on the information available about this Thing, the RDF browser will shape its interface to optimize users’ browsing experience with the data.

Sources of data

Data displayed in the Zitgist RDF Browser can come from many different data sources:

  • Zitgist’s internal RDF datastore
  • URI dereferencing
  • On-the-fly conversation of data sources such as:
    • Microformats
    • RDFa
    • eRDF
    • HTML meta tags
    • API data source such as:, Google Base, etc.

So, depending on what information is available for a given URI, the browser will mesh-up these data sources and displays the information to the user.

First example of the templating system


This first example shows how the browser will create a web page out of a RDF data source. In this case, the data source is a URI where Madonna’s latest album “Confession on a Dance Floor” is described.

  1. The browser will check for that URI:
  2. No information is available in its data store, so it will dereference the URI to get the RDF triples describing the album.
  3. All in all, 15 different URIs will be dereferenced to create the web page.
  4. The browser will detect that the type of the entity related to this URI is a mo:Album; so it will triggers the “moAlbum” template to skin the data source so that the user can easily see and understand the information we have about this resource (music album).
  5. Then the skinned information is displayed to the user.

The templating system in action

Now we will see the templating system in action. In fact, the RDF browser does much more than skinning a single data source.


If you put that URI in the browser, you will see Sebastian’s profile. The browser will fire the foafPerson template, and his profile will be skinned according to this template.

However, what is interesting in that example is not only Sebastian’s profile, but the entities it links to. In fact, if you take a closer look and go down the page a little bit, you will notice the “Current projects” section of his profile. Then you will see a list of projects.


The first project is a musical group described as a foaf:Group. So, the browser will check the URI Sebastian’s profile link to, get information about it, skin it accordingly to the foafGroup template, and embed the result within Sebastian’s profile page.

Since we could embed such entities at infinitum, the browser restricts this automatic browsing to 3 deep levels in the graph.

Finally, we can “lookup” an individual embedded item by clicking on the lookup icon at the upper right corner of each entity.

Sidebar Navigator

In some cases some generated web page can be quite large, so a navigation widget has been developed to help users to navigate generated documents. The navigation of a document is based on the entities displayed in it.

For example, if we run the Zitgist RDF Browser for that URI:, we will notice that information displayed is many pages long. So, to help us navigating this long document, we will use the entity navigator widget.



All the types available in that web page are listed in the sidebar, and for each type you have all the instances available.

In that example, you can easily browse the web feed of that web page. In a click, you can see all Posts, Feeds and Authors.

Interesting examples

There is a list of starting points to see the Zitgist RDF Browser in action:

  • And all the examples above.


The Zitgist RDF Browser can process any URI. So, from any web page, a user can launch the browser to see what semantic web information is available for that URI. Then, all the information the browser can find/generate out of that data source will be displayed to the user.

To help users, I developed this really simple bookmarklet that get the URI of the current web page, send it to the browser, and then redirect the user to the browser’s generated page.

Zitgist RDF Browser’s Bookmarklet



As you noticed above, this new RDF browser is a sort of information shape-shifter. Depending on the information available for a given URI, it will skin it to make it easier to browse and understand for users.

Semantic Web, Zitgist, Music Ontology

The Music Data Space

Kingsley is talking about Data Spaces since a long time. But what is a Data Space? Nothing is better than an example to understand something, so I will try to explain you with a single data space that has been created yesterday, the Music Data Space:


This is the Music Data Space. This Data Space contains information about musical things. These things are described mainly by using the Music Ontology, but also by using other ontologies like FOAF. Finally, things (musical things) belonging to this space are accessible, on the Web, via dereferencable URIs.

So, the Music Data Space is a place where all musical things are defined on the Semantic Web, and accessible via the Web.

That is it, and it is what we created last Monday.

Now, some of you could wonder: why on earth belongs to the Music Data Space? also belongs to the Music Data Space too! live in the Music Data space too via their API. In fact, a simple experience with the OpenLink RDF Browser clearly demonstrates that’s data belongs to the Music Data Space too.

Open the RDF Browser by following that link

Now you will visualize RDF information about an album called “Chore of Enchantment”. Take a look at this line:


Click on the link to Amazon. A window should popup. Select the Get Data Set (dereference) option.

At this point, some magic will happens. In fact, the new information that is displayed in the RDF Browser is coming directly from’s web server.

This is why I assume that belong to the Music Data Space too.

In fact, the Virtuoso Sponger will connect to via their API to get some information about that album. It will convert the data into RDF and will display it to the user via the RDF browser’s interface.

One step further: the JPG file also belongs to the Music Data Space!

Yes! Information about the JPG file, hosted on’s web servers, also belong to the Music Data Space and there is the proof:

Open that same RDF Browser page by following that link

Click on the Image (JPG) representing the cover of this album. A window should popup. Select the Get Data Set (dereference) option.

Check the triples that have been created from this image. The Virtuoso Sponger downloaded the JPG file, it analyzed its header, RDFized everything and sent the information back to the RDF Browser so that the user can see the information available for that image.

Where is the end? I have no idea… probably at the same place where the imagination ends too.

Unifying everything

This is that simple. All data sources (relational databases, remote data accessible via APIs, native rdf data, etc.) are unified together via the Music Data Space. And this Music Data Space is accessible, via URI dereferencing, at

Other Data Spaces available


The Music Data Space is the starting point and many other type of data spaces should emerge soon.

Semantic Web, Zitgist, Music Ontology

Browsing Musicbrainz’s dataset via URI dereferencing

Musicbrainz’s dataset can finally be browsed, node-by-node, using URI dereferencing.

What this mean?

Since the Musicbrainz relational database has been converted into RDF using the Music Ontology, all relations existing between Musicbrainz entities (an entity can be a Music Artist, a Band, an Album, a Track, etc.) are creating a musical relations graph. Each node of the graph is a resource and each arc is a property between two resources. Welcome in the World of RDF.


This means that from a resource “Madonna” we can browse the musical relations graph to find other entities such as Records, People, Bands, Etc.

Kingsley, inspired by Diana Ross, said: “URI Everything, and Everything is Cool!

This is cool! Now Diana Ross has her own URI on the semantic web:

Paul McCarney:

The Beatles:


Have their own too!

URIs for Musical Things

These URIs are not only used to refer to Musicbrainz entities. In fact, these URIs are used to refer to any Musical Entities that you can describe using the Music Ontology. In a near future, the Musicbrainz data will be integrated along with data from Jamendo and Magnatune. In the future, we will be able to integrate any sort of musical data at the same place (radio stations data, user foaf profiles relations to musical things, etc.). So from a single source ( all these different sources of musical data will be queriable at once.


URI schemes

The URI schemes are defined in the Musicbrainz Virtuoso RDF View:


All these URI schemes terms refer to their Music Ontology classes’ descriptions.


I am getting closer and closer to the first goal I set to myself when I first started to write the Music Ontology. This first goal was to make the Musicbrainz relational database available in RDF on the Web. Months later and with the help of the Music Ontology Community (specially Yves Raimond that worked tirelessly on the project) and the OpenLink Software Inc. Team, we finally make this data available through URI dereferencing.

From there, we will build-up new music services, integrate more musical datasets into the Music Data Space, etc. It is just the beginning of something much bigger.


Gone for the next 2 weeks

I am leaving tomorrow morning for the California until the 11 May. Until then I will be reachable via email, but with some latency, so please pardon me if I don’t answer the same day you send the email.

Do not hesitate to send me an email if you have questions, comments or suggestions about my works, I will be a pleasure for me to answer to them, it will just take a little bit longer than usually.