Monday, September 27, 2010

Visualizing data embedded in XHTML+RDFa

Orion picked up my challenge and made an web based application to graph data from one of my XHTML-RDFa pages. Well done! He wrote his work up in his blog of which the results looks like:

The text field shows the SPARQL used to aggregate the data, which is then visualized in the plot below that field. You can edit the SPARQL and, for example, plot the boiling point (t) as function of the number of carbons (p):

This work nicely shows some interesting McPrinciples: it shows what happens if we allow reuse and share our knowledge; it shows that nice graphics and semantic access to original data are very compatible. All in all, this is an important step forward to semantic publishing of chemical data! Orion, thanx for this really nice work!


  1. The semantic web: I want to believe. I really do... I genuinely appreciate the spirit of 'experimentation' on your blog, especially with semantic web technologies. This is a neat practical example, I wasn't ware you'd taken RDFa this far with embedded data for figures. I wonder if all we really need for data-rich (which buzz word ?) publications is an html document with RDFa. A couple of additional points, I guess you could do this directly in javascript without the need for the service. And I also wonder if RDFa is compatible with HTML5. Great work, I look forward to seeing how this evolves.

  2. Hi Greg,

    the Semantic Web is really a change in thinking for scientists... we cannot get away any more with fiddling around a bit and telling nice stories; we now have to be accurate in what we say. That is difficult, not just for scientists. This is why most people like HTML more than XHTML; the details are less important.

    There are actually various levels at which publishing can be improved; this could be one, and is at least one I am using in educational material.

    I fully agree that we need a SPARQL engine in JavaScript; it would indeed simplify things greatly. I can imagine future visualization toolkits to have support for RDFa itself.

    RDFa is indeed compatible with HTML, not just XHTML. I personally just like the last bit somewhat more, as validation of the correctness is easier (XHTML is much easier to parse then HTML). They are working on a HTML5 module for RDFa, which is, of course, work in progress, as HTML5 is still too. This is the current specification: