Quatro vocabulary schema description

Contents

• Introduction
• Example of use
• Mixing with other schemas
• The Quatro codes in full

Introduction

The Quatro vocabulary is defined in two separate documents: one for humans to read [DEF], the other is expressed as an RDF schema [RDFS] and is for machines to read. This document links the two and enables developers to use the machine-readable version in applications

The Quatro namespace is http://purl.org/quatro/elements/1.0/ and the recommended QName is quatro. The schema itself can be accessed from the namespace URL.

The schema declares that the permitted values for each descriptor is a Boolean, as defined in the XML Schema [XSD]. It is further declared that descriptors have a domain of Content Label as defined in the RDF Content Label schema. [RDF-CL].

Example of use

The following example shows the key elements.

<?xml version="1.0"?>
<rdf:RDF
  xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
  xmlns:label="http://www.w3.org/2004/12/q/contentlabel#"
  xmlns:dc="http://purl.org/dc/elements/1.1/"
  xmlns:dcterms="http://purl.org/dc/terms/"
  xmlns:quatro="http://purl.org/quatro/elements/1.0/#">

  <rdf:Description rdf:about="">
    <dc:creator rdf:resource="http://www.trustmarkscheme.com" />
    <dcterms:issued>2005-08-05</dcterms:issued> 
    <label:authorityFor>http://purl.org/quatro/elements/1.0/</label:authorityFor>
  </rdf:Description>

  <label:Ruleset rdf:ID="Ruleset">
    <label:hasHostRestrictions>
      <label:Hosts>
        <label:hostRestriction>example.org</label:hostRestriction>
      </label:Hosts>
    </label:hasHostRestrictions>
    <label:hasDefaultLabel rdf:resource="#label_1"/>
  </label:Ruleset>

  <label:ContentLabel rdf:ID="label_1">
    <rdfs:label xml:lang="en">Providing suitable identification information; 
      Use of clear language that is fit for purpose; Privacy statement; 
      Content provider credentials; Providing relevant information 
      about content; Fair commercial communications and fair marketing 
      practices; Protection of children; Providing information on goods 
      and services; Providing contract information</rdfs:label>
    <quatro:ga>1</quatro:ga>
    <quatro:gb>1</quatro:gb>
    <quatro:gc>1</quatro:gc>
    <quatro:gf>ES</quatro:gf>
    <quatro:gf>PT</quatro:gf>
    <quatro:aa>1</quatro:aa>
    <quatro:ab>1</quatro:ab>
    <quatro:ra>1</quatro:ra>
    <quatro:rb>1</quatro:rb>
    <quatro:rc>1</quatro:rc>
    <quatro:rd>1</quatro:rd>
    <quatro:gk rdf:resource="quatro:WAI-A" />
  </label:ContentLabel>
</rdf:RDF>

Section 1 declares the required namespaces.

Section 2 describes the RDF document itself, when and by whom it was issued, and for which namespaces that labelling organisation is an authority. The last item is provided so that if the RDF instance contains descriptions from other schemes (perfectly possible!) then the responsibility for the use of the Quatro descriptors remains clear.

Section 3, the Ruleset, defines for which hosts the RDF instance can be applied and what the default label is. The data here says that the default Content label for example.org is "label_1".

Section 4 is the label itself. The majority of the descriptors have a Boolean value but two differ from this. First of all quatro:gf which states the labelled resource meets legal practice in ES and PT (Spain and Portugal). Secondly, the final descriptor declares that the labelled resource meets the W3C's Web Accessibility Guidelines to "level A."

Mixing with other schemas

RDF-CL is a specialised use case for RDF itself [RDF], designed as a platform for carrying any kind of metadata and as the foundation of the semantic web [SW]. It is anticipated that any trust mark scheme using the Quatro vocabulary will use only a portion of it and will want to add their own descriptors too. A Content Label may look more like the example below which includes terms from the Quatro and ICRA schemas plus another "example.".

<label:ContentLabel rdf:ID="label_ex">
  <quatro:ga>1</quatro:ga>
  <quatro:gb>1</quatro:gb>
  <quatro:gf>ES</quatro:gf>
  <quatro:gf>PT</quatro:gf>
  <quatro:rb>1</quatro:rb>
  <quatro:rc>1</quatro:rc>
  <quatro:rd>1</quatro:rd>
  <ex:terma>1</ex:terma>
  <ex:termb>1</ex:termb>
  <extermc>1</extermc>
  <icra:nz>1</icra:nz>
  <icra:sz>1</icra:sz>
</label:ContentLabel>

The RDF-CL schema also has support for other types of labelling and classification schemes and developers are encouraged to familiarise themselves with the many options.

The Quatro codes in full

Links and references

[DEF]

http://www.quatro-project.org/vocabulary/1.0/

[RDFS]

http://www.w3.org/TR/rdf-schema/

[XSD]

http://www.w3.org/2001/XMLSchema

[RDF-CL]

RDF Content Labels: Schema Description

[RDF]

http://www.w3.org/RDF/

[SW]

http://www.w3.org/2001/sw/

[ICRA]

http://www.icra.org/