I'm in the process of constructing a DCAT catalogue and we want to show how each dataset conforms to the 5-star open data rating scheme. I assumed that someone would have coined URIs for each rating but have been unable to find them.

Do such URIs exist?

  • just to be clear, you are asking if 5-Star OD Ratings have namespaced URIs, that you can point to?
    – albert
    Sep 21, 2016 at 23:31
  • Yes, how else would the 5 star scheme earn it's own 5th star? ;)
    – chrisis
    Sep 22, 2016 at 7:53
  • Pointing to a namespace, and being a namespace are two different things, hence the need for clarification.
    – albert
    Sep 22, 2016 at 13:33
  • regardless, i asked because each one of those examples has uri's, so if that is what you seek, they have been there the whole time.
    – albert
    Sep 22, 2016 at 19:48
  • I was looking for URIs that identified the star level in an established/ vocabulary and resolved in a way that supplied some useful context i.e. linked. I'm only seeing links to examples from a web page that has changed since January.
    – chrisis
    Sep 22, 2016 at 21:45

2 Answers 2


I'm not sure I agree that you need to have any URI to demonstrate how open a set of data is. Either the data is open and shareable or it is not, the openness of the data is described by the openness of the data.

Let's say I publish a set of RDF linked data, as soon as it is published it is open to be consumed as a whole or in part, people can take which bits they want to put in a triple store or use how they like, so where do you put the link to the accreditation, I mean you can't link it to everything directly.

But OK, you want some URI that you can publish in a metadata catalogue, that documents the openness of the data described by the metadata, then why not use the Linked Open Data star badges


enter image description here no star Web data


enter image description here one star open Web data


enter image description here two star open Web data


enter image description here three star open Web data


enter image description here four star open Web data


enter image description here five star open Web data

  • I was hoping for URIs that resolved providing further information (TB-Ls third rule). Granted, you could argue a picture is further information ;) . I'm going to mark this answer as being the most helpful. A shorter answer to my original question might be - "No, but here's the best alternative".
    – chrisis
    Dec 22, 2016 at 13:21

Short answer

You should create these URIs yourself, as well as mainteiners of all other DCAT catalogues.

Long answer

Look at Data Quality Vocabulary, which is based on DCAT. Consider the following example from the section 6.7:

    a dcat:Dataset ;
    dqv:hasQualityAnnotation :classificationQA .

    a dqv:UserQualityFeedback ;
    oa:hasTarget <https://certificates.theodi.org/en/datasets/393> ;
    oa:hasBody :four_stars ; 
    oa:motivatedBy dqv:qualityAssessment, oa:classifying ;
    dqv:inDimension :availability .

   a skos:Concept;
   skos:inScheme :OpenData5Star ;
   skos:prefLabel "Four stars"@en ;
   skos:definition "Dataset available on the Web with structured
   machine-readable non proprietary format. It uses URIs to denote things."@en .

Data Quality Vocabulary implicitely prescribes creation of your own concept of 5 star rating scheme.


DQV is aligned with the daQ ontology for representing information on the quality of linked open datasets, which is itself anchored in the RDF Data Cube framework for publishing statistical data.

There are dimensions, metrics, observations of quality. The classification of a dataset as a three star dataset is just a derivation from the result of a availability measurement performed by a measurer.

    dqv:hasQualityAnnotation  :myDatasetClassification .

    a dqv:UserQualityFeedback ;
    prov:wasDerivedFrom  :measurement2 ;
    oa:hasTarget :myDataset ;
    oa:hasBody :three_stars ; 
    oa:motivatedBy dqv:qualityAssessment, oa:classifying ;
    dqv:inDimension :availability .

    a dqv:QualityMeasurement ;
    dqv:computedOn :mySPARQLDatasetDistribution ;
    dqv:isMeasurementOf :SPARQLAvailabilityMetric ;
    dqv:value "false"^^xsd:boolean .

As you can see, DQV uses the Web Annotation Vocabulary. It means that dataset quality lies entirely in the eye of the beholder, and all abstract notions involved have to be defined by this beholder, unless they are defined in the Web Annotation Vocabulary.

See also ISSUE-148 and the discussion related.

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