Basic Example

This example provides a quick overview of how DCAT might be used to represent a government catalog and its datasets.

First, the catalog description:

   :catalog
       a dcat:Catalog ;
       dct:title "Imaginary Catalog" ;
       rdfs:label "Imaginary Catalog" ;
       foaf:homepage <http://example.org/catalog> ;
       dct:publisher :transparency-office ;
       dct:language <http://id.loc.gov/vocabulary/iso639-1/en>  ;
       dcat:dataset :dataset-001  , :dataset-002 , :dataset-003 ; 
       .

The publisher of the catalog has the relative URI :transparency-office. Further description of the publisher can be provided as in the following example:

   :transparency-office
       a foaf:Organization ;
       rdfs:label "Transparency Office" ;
       .

The catalog lists each of its datasets via dcat:dataset property. In the example above, an example dataset was mentioned with the relative URI :dataset-001. A possible description of it using DCAT is shown below:

   :dataset-001
       a dcat:Dataset ;
       dct:title "Imaginary dataset" ;
       dcat:keyword "accountability","transparency" ,"payments" ;
       dct:issued "2011-12-05"^^xsd:date ;
       dct:modified "2011-12-05"^^xsd:date ;
       dcat:contactPoint <http://example.org/transparency-office/contact> ;
       dct:temporal <http://reference.data.gov.uk/id/quarter/2006-Q1> ;
       dct:spatial <http://www.geonames.org/6695072> ;
       dct:publisher :finance-ministry ;
       dct:language <http://id.loc.gov/vocabulary/iso639-1/en>  ;
       dct:accrualPeriodicity <http://purl.org/linked-data/sdmx/2009/code#freq-W>  ;
       dcat:distribution :dataset-001-csv ;
       .

In order to express frequency of update in the example above, we chose to use an instance from the Content-Oriented Guidelines developed as part of the W3C Data Cube Vocabulary efforts. Additionally, we chose to describe the spatial and temporal coverage of the example dataset using URIs from Geonames and the Interval dataset from data.gov.uk, respectively. A contact point is also provided where comments and feedback about the dataset can be sent. Further details about the contact point, such as email address or telephone number, can be provided using VCard [[vcard-rdf]].

The dataset distribution :dataset-001-csv can be downloaded as a 5Kb CSV file. This information is represented via an RDF resource of type dcat:Distribution.

   :dataset-001-csv
       a dcat:Distribution ;
       dcat:downloadURL <http://www.example.org/files/001.csv> ;
       dct:title "CSV distribution of imaginary dataset 001" ;
       dcat:mediaType "text/csv" ;
       dcat:byteSize "5120"^^xsd:decimal ;
       .

Classifying datasets

The catalog classifies its datasets according to a set of domains represented by the relative URI :themes. SKOS can be used to describe the domains used:

   :catalog dcat:themeTaxonomy :themes .

   :themes
       a skos:ConceptScheme ;
       skos:prefLabel "A set of domains to classify documents" ;
       .

   :dataset-001 dcat:theme :accountability  .

Notice that this dataset is classified under the domain represented by the relative URI :accountability. It is recommended to define the concept as part of the concepts scheme identified by the URI :themes that was used to describe the catalog domains. An example SKOS description:

   :accountability 
       a skos:Concept ;
       skos:inScheme :themes ;
       skos:prefLabel "Accountability" ;
       .

Describing catalog records metadata

If the catalog publisher decides to keep metadata describing its records (i.e. the records containing metadata describing the datasets), dcat:CatalogRecord can be used. For example, while  :dataset-001 was issued on 2011-12-05, its description on Imaginary Catalog was added on 2011-12-11. This can be represented by DCAT as in the following:

   :catalog  dcat:record :record-001  .

   :record-001
       a dcat:CatalogRecord ;
       foaf:primaryTopic :dataset-001 ;
       dct:issued "2011-12-11"^^xsd:date ;
       .  

A dataset available only behind some Web page

:dataset-002 is available as a CSV file. However :dataset-002 can only be obtained through some Web page where the user needs to click some links, provide some information and check some boxes before accessing the data

   :dataset-002 
       a dcat:Dataset ;
       dcat:landingPage <http://example.org/dataset-002.html> ;
       dcat:distribution :dataset-002-csv ;
       .
   :dataset-002-csv 
       a dcat:Distribution ;
       dcat:accessURL <http://example.org/dataset-002.html> ;
       dcat:mediaType "text/csv" ;
       .

A dataset available as download and behind some Web page

On the other hand, :dataset-003 can be obtained through some landing page but also can be downloaded from a known URL.

   :dataset-003 
       a dcat:Dataset ;
       dcat:landingPage <http://example.org/dataset-003.html> ;
       dcat:distribution :dataset-003-csv ;
       .
   :dataset-003-csv 
       a dcat:Distribution ;
       dcat:downloadURL <http://example.org/dataset-003.csv> .
       dcat:mediaType "text/csv" ;
       .