RE: W3C Data Exchange Working Group: Invitation to review draft revision of DCAT

Dear DXWG,

I would like to thank you for your considerable effort in the revision of DCAT. As designer and main author of EPOS-DCAT-AP (https://github.com/epos-eu/EPOS-DCAT-AP) I appreciate very much the new features you introduced. To respond to the requirements of our communities we had to accommodate functionalities in our profile that are now supported natively. In particular, the introduction of additional resources (beyond Dataset) as first-class citizens in a Catalogue was definitely required and we accommodated that by extending DCAT 2014. My view is that in the context of RIs catalogues have an essential role to represent a variety of assets -- having the focus only on Dataset would be too restrictive. Therefore, I am pleased to see that there is a dcat:Resource in this new version. Also, two specialisations of a dcat:Resource are provided: Dataset and DataService. I assume that more might be added to extend the scope of a Catalogue when needed. Am I correct? Do you support composition of resources? Would that be covered by dct:relation?
Also, I would be interested in the approach you are considering to tackle Issue 66 and Issue 71.

Another important feature for us is the support for Data Services. I like your solution and I would like to understand a bit more about how to deal with a service that is providing multiple datasets e.g. by different methods/operations. I agree that the description of a service, via dcat:endpointDescription, should be as much as possible relying on dedicated description standards (e.g. WADL, OpenAPI/Swagger, OpenSearch). However, in some cases where such descriptions are not available a templating approach might be useful. In our case, while promoting the first approach, we also provided an alternative by embedding the W3C Hydra Vocabulary. For instance, Templated Links can be used. Hydra offers quite extensive descriptions although its status (Unofficial Draft) makes its adoption and future support unclear.

About Organization and Person. I think it might be useful to make them explicit in the model in order to facilitate relationships between them and with their associated resources.
For instance, a Person belonging to an Organization, her roles etc. Did you consider adding additional roles beyond publisher, creator and contributor? Why the latter applies only to CatalogRecord?

Finally, I think the alignments with other standards are very important, e.g. Schema.org and PROV. We found it very useful to import elements of Schema.org directly in our profile. We also discussed the introduction of PROV and therefore I appreciate that some elements are now available: e.g. prov:wasGeneratedBy.

In conclusion I would like to thank you all again for this new revision and its substantial improvements. They will facilitate uptake and usability of the model in broader contexts.
I look forward to seeing a finalised version.

Kind regards,
Luca Trani


Luca Trani
Senior Advisor IT - Researcher
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KNMI
Ministry of Infrastructure and Water Management
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Van: Alejandra Gonzalez-Beltran [mailto:alejandra.gonzalez.beltran@gmail.com]
Verzonden: dinsdag 23 oktober 2018 09:55
Aan: public-dxwg-comments@w3.org
Onderwerp: W3C Data Exchange Working Group: Invitation to review draft revision of DCAT

Dear All,

This mail is to update you on the work of the W3C Data Exchange Working Group [1] and to ask for your help in reviewing progress on the revision of the RDF vocabulary for data catalogues, DCAT, that was published on 16 October 2018. The draft of the revision is available at https://www.w3.org/TR/vocab-dcat-2/.

The revision of DCAT is part of a group of 3 deliverables described in the Charter [2], but it is able to stand up by itself as an update to the recommended way in which data catalogues should be published on the web.
The main ways in which this first draft revision differs from the current recommendation include:

  *   the scope of DCAT is extended to include data services and data distribution services, as well as datasets, as members of a catalog
  *   some initial recommendations concerning the use of elements from the W3C PROV-O vocabulary for Dataset provenance
  *   recommendations for catalogs with lower expressivity, concerning the relations between Datasets and associated resources
  *   recommendations concerning the description of dataset quality, primarily using DQV (from the Data on the Web Working Group)
  *   some minor adjustments to support citation of all catalogued resources
  *   more relaxed axiomatisation that gives greater flexibility to the domain and range Classes of several predicates
In addition, among other things, we are working on:

  *   ways of dealing with related datasets (including sub-datasets)
  *   further recommendations regarding use of PROV-O elements and patterns in DCAT descriptions
  *   patterns for dataset versioning
In reviewing the draft it might be helpful for you to keep in mind the “Use Cases and Requirements” document that we are working to [3].
We would find it helpful to get feedback on the following lines:

  1.  Do you agree with the direction of travel of this revision of DCAT?
  2.  Are there any areas where we could improve what we have done? [please illustrate]
  3.  Are there any areas where you think the proposal is wrong or could lead us into developing proposals that are erroneous? [please give examples and reasons]
  4.  Are there other use cases for data catalogues and datasets descriptions that we have not considered [please illustrate]
Please also feel free to make any other comments and suggestions regarding the draft. Note that positive comments or general assent to changes are very welcome, as these provide evidence of community acceptance.
Please, send comments through GitHub issues (https://github.com/w3c/dxwg/issues) or through email at public-dxwg-comments@w3.org<mailto:public-dxwg-comments@w3.org>.
Best wishes

Alejandra (on behalf of the W3C DXWG)

[1] https://www.w3.org/2017/dxwg/wiki/Main_Page

[2] https://www.w3.org/2017/dxwg/charter

[3] https://www.w3.org/TR/dcat-ucr/