Seth Ladd's Blog

GRDDL is out, providing a mechanism for providing instructions to convert documents on the web into RDF . In short, GRDDL allows you to link an XSLT transform to your XHTML page, which converts the XHTML into an RDF document. For more information, start at the GRDDL Primer . (The irony is that while you can use XSLT to convert into RDF, you can't ever use XSLT to convert RDF into something else with complete certainly because RDF/XML output is nondeterministic.) The primer includes a few examples of using SPARQL to query the RDF document generated by a GRDDL transform. Here's an example from the primer: PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> PREFIX rev: <http://www.purl.org/stuff/rev#> PREFIX vcard: <http://www.w3.org/2006/vcard/ns#> PREFIX dc: <http://purl.org/dc/elements/1.1/> PREFIX foaf: <http://xmlns.com/foaf/0.1/> SELECT DISTINCT ?rating ?name ?region ?hotelname FROM <http://www.w3.org/TR/grddl-primer/hotel-data.rdf>...

RDF/A Primer 1.0 is an effort to allow embedding RDF into XHTML. To me, this problem of "How do I get my RDF into my web pages?" is only second to creating a friendly RDF XML format. Solve these two problems and you'll immediately see a greater adoption of semantic web technologies. > RDF/A is a set of attributes used to embed RDF in XHTML. An important goal of RDF/A is to achieve this RDF embedding without repeating existing XHTML content when that content is the metadata. Though RDF/A was initially designed for XHTML2, one should be able to use RDF/A with other XML dialects, e.g. XHTML1, SVG, given proper schema additions. From what I could see, this is a simple way to add more semantics to your web page. It doesn't appear that the authors explicitly mention how to get the semantics out of the document, though. However, I've never been too fond on GRDDL and it's use of XSLT so hopefully RDF/A will provide an easier metadata extraction technigue.