Update: If you’re interested in expressing statistics in RDF, I’d encourage you to join the publishing statistical data group and take a look at the documentation for ‘SDMX-RDF’ described there.
One of the things that we’ve been discussing over on the UK Government Data Developers mailing list is how best to represent the vast quantities of statistical data that the government produces, in RDF. This is what we’ve come up with.
This week, the Cabinet Office went live with a preview version of hmg.gov.uk/data, available only to those who subscribe to the UK Government Data Developers Google Group. Harry Metcalfe has written a great review, or of course you can check it out yourselves.
Already, though, there are discussions starting on the mailing list about how the data is being made available, and I’m worried that these might distract us from getting things done.
When Leigh Dodds presented about Linked Data at the XML Summer School this year, one of the things he suggested was that when you have a controlled vocabulary, you should define resources for the terms in that vocabulary rather than having a fixed set of literal values.
For example, if you’re saying that the topic of a page is elephants you should use a triple like:
<> dc:subject <http://example.com/id/concept/animal/elephant> .
rather than one like:
<> dc:subject "elephant"^^xsd:token .
One of the fundamental disconnects between HTML5 and previous versions of HTML is the way in which you answer the question “what is the structure of this page?”. Things that make use of that structure, such as RDFa, need to take this into account.
An example is the document:
<html> <head><title>HTML example</title></head> <body> <table> <span>Example title</span> <tr><td>Example table</td></tr> </table> </body> </html>
This post is about how to name properties and relations in RDF schemas. Or rather, about how different ontology developers use different conventions and how this can sometimes be confusing.
Part of the work that I’ve been doing over the last few months at TSO has been for OPSI, who want to provide information about UK legislation for reuse through an API as well as eventually through a new end-user service. The Single Legislation Service API is now available, in beta, if you want to take a look.
One way in which we’re providing information about legislation is using RDF/XML. An example is the Criminal Justice Act 1993 Section 67, for which RDF is available at http://legislation.data.gov.uk/ukpga/1993/36/section/67/data.rdf. For now, we’ve made the decision to not attempt to create any of our own ontologies for the RDF, but to reuse ones that are already out there.