280,635,980 triples

This service hosts (almost) all Dutch national regulations in CEN MetaLex XML and as RDF Linked Data. Current coverage is 33,706 document versions, covering practically all regulations available through http://wetten.overheid.nl

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Information

This service hosts (almost) all Dutch national regulations in CEN MetaLex XML and as RDF Linked Data. Current coverage is 33,706 document versions, covering practically all regulations available through http://wetten.overheid.nl

This server was developed by Rinke Hoekstra and is maintained by the Leibniz Center for Law of the Universiteit van Amsterdam.

The regulations were automatically converted by means of a (hopefully) generic conversion script, that is able to perform a similar conversion for any 'legislative' XML based on a standard mapping from legacy XML elements to CEN MetaLex. See the script's GitHub page for installation and usage instructions.

A report on this work will be published as part of the proceedings of the International Semantic Web Conference (ISWC) 2011: "Rinke Hoekstra. The MetaLex Document Server - Legal Documents as Versioned Linked Data"

View presentation »

MetaLex and Linked Data

CEN MetaLex is a standard for how sources of law and references to sources of law are to be represented in XML. It is an interchange format, a lowest common denominator for other standards, intended not to replace jurisdiction-specific standards and vendor-specific formats in the publications process but to impose a standardized view on legal documents for the purposes of information exchange and interoperability in the context of software development.

Linked Data is a W3C sanctioned approach to publishing metadata on the Web using a set of standard languages and metadata vocabularies.

MetaLex »Linked Data »

Example

The following links are several example URIs for the "Regeling beleidsregels vereveningsbijdrage zorgverzekering 2006" (See here for the document on Overheid.nl). Clicking on any of them, will redirect to a Marbles browser of the RDF metadata about the regulation.

Alternatively, you can access the document directly, by using a 'manifestation' (or 'document') URI that identifies the document (or part of it) in one of the available formats:

You can try out content negotiation with tools such as 'wget' or 'curl' to retrieve non-HTML content from the 'expression' and 'work' level URIs.

Technical Details

Metadata

Metadata follows the guidelines of the CEN MetaLex standard. Legislative events are represented both by means of the MetaLex ontology, as well as using the Open Provenance Model vocabulary (OPMV), the Simple Event Model (SEM) and the W3C Time Ontology.

Store

RDF representations of regulations reside in a 4store triple store, developed at Garlik.

MetaLex XML documents currently reside on the filesystem of the server. We plan to move these to a native XML database to support XQuery access to their structure.

Cool URIs

Resources available on this server are disclosed by means of Cool URIs.

That is, depending on the accept header sent by the client that performs an HTTP request to the URI of a resource, the server performs a 2-step redirect (actually 3, in this case) to the manifestation that is interpretable by the client. A manifestation is essentially a version of (part of) a document (an expression) in a certain format.

This server is able to handle the following content types:

  • HTML: application/xml, application/xhtml+xml, text/html
  • RDF/XML: application/rdf+xml
  • Turtle: text/rdf+n3, application/x-turtle
  • XML: text/xml
  • Net: text/plain

URI resolution works as follows:

  • A request for an expression URI (i.e. one that starts with 'http://doc.metalex.eu/id/...' ) is redirected by means of an HTTP 303 to a document URI (one that starts with 'http://doc.metalex.eu/doc/...')
  • This leads to a request for the document URI.
  • We then parse the HTTP accept header of the request, and redirect (via HTTP 302) to the URI of the manifestation URI (i.e. a URI ending with data.rdf, data.n3, data.ttl, data.html, data.xml or data.net)
  • For XML and NET files, we then redirect (via HTTP 302) to the URL of the actual file that contains the description of the resource.
  • For RDF, Turtle and N3 we directly return the the result of a SPARQL DESCRIBE query for the expression URI.
  • For HTML, we redirect (via HTTP 302) to a Marbles server that renders an HTML representation of the result of a SPARQL DESCRIBE query for the expression URI. (Marbles actually sends a request to the expression URI with an accept header that makes this server redirect to the RDF description)

Copyright (c) 2011 - Rinke Hoekstra, Leibniz Center for Law, Universiteit van Amsterdam