Methodology

We followed the steps described below to collect evidence for the revisions proposed in [[VOCAB-DCAT-2]]:

1. Identify the actual list of revisions proposed in [[VOCAB-DCAT-2]] for which implementation evidence should be collected (see for more details).
2. Review existing vocabularies based on [[VOCAB-DCAT]], and identify if they include already the changes proposed in [[VOCAB-DCAT-2]], and/or their alignment with [[VOCAB-DCAT-2]] is planned. The rationale for including also planned implementations is that these vocabularies are not likely to adopt the revisions proposed in [[VOCAB-DCAT-2]] until it becomes a W3C Recommendation.
3. Review existing guidelines and implementation reports of [[VOCAB-DCAT]], as well as of vocabularies based on it, to verify if the changes proposed [[VOCAB-DCAT-2]] are implemented in existing data catalogs, data services, and datasets.
4. Develop an Implementation Report with details of the steps above.

As noted, to have a broader coverage of [[VOCAB-DCAT-2]] adoption we considered different types of evidence:

1. DCAT-based vocabularies
2. Data catalogs, data services, and datasets

Due to the large number of DCAT-based vocabularies and data catalogs supporting [[VOCAB-DCAT]], this report includes only a representative subset, providing nonetheless enough implementation evidence of the revisions proposed in [[VOCAB-DCAT-2]].

Meeting the exit criteria

As described in the DXWG charter, to advance to Proposed Recommendation, evidence will be adduced in order to demonstrate that each of the changes made to the original DCAT Recommendation [[VOCAB-DCAT]] has been published and consumed independently in catalogs and related systems at least once, although a higher number is expected for the majority of terms.

Evidence of implementation was gathered from existing data catalogs, data services, and datasets, which already implement the proposed changes, as well as from existing application profiles of [[VOCAB-DCAT]].

DCAT-based vocabularies

The following table shows DCAT-based vocabularies providing implementation evidence of the revisions proposed in [[VOCAB-DCAT-2]].

The criteria used to select the relevant vocabularies are the following ones:

1. They are based on [[VOCAB-DCAT-2]] or they extend [[VOCAB-DCAT]] with properties and classes included in [[VOCAB-DCAT-2]].
2. Preferably, they are used across multiple data catalogs and/or domains/disciplines.

At the time this report was written, it was not possible to identify vocabularies based on [[VOCAB-DCAT-2]]. However, there are quite a few vocabularies extending [[VOCAB-DCAT]] - a non-exhaustive list is included in § 14 DCAT Profiles of [[VOCAB-DCAT-2]]. Among these, we have selected the most representative ones, for geographic and domain coverage as well as tooling support, which already include at least some of the revisions proposed in [[VOCAB-DCAT-2]], and/or whose alignment with [[VOCAB-DCAT-2]] is under way or planned.

The vocabularies listed earlier in this section have been chosen for the following reasons:

• [[DCAT-AP]] is a profile of [[VOCAB-DCAT]] used across Europe since 2014 as a metadata interchange format, primarily for catalogs of government data, and, to some extent, for scientific data. As such, it has a broad geographic coverage, and it is supported in data catalogs (e.g., the European Data Portal) and catalog platforms (e.g., CKAN).
• [[GeoDCAT-AP]] and [[StatDCAT-AP]] are domain-specific extension of [[DCAT-AP]] for geospatial and statistical data, respectively, and they share the same geographic coverage of [[VOCAB-DCAT]].
• [[CiteDCAT-AP]] and [[DCAT-AP-JRC]] are extensions of [[DCAT-AP]] specifically designed for multidisciplinary research data, and they are implemented in the corporate catalog of the European Commission's Joint Research Centre. Moreover, [[CiteDCAT-AP]] is supported in Zenodo, the research data catalog and repository most widely used in Europe.

[[DCAT-AP]] has also been used as a basis for the development of country-specific extensions (see [[DCAT-AP-EXT]]). Such extensions have not been included in this report, but they provide additional support to the implementation evidence for the revisions proposed in [[VOCAB-DCAT-2]] already included in [[DCAT-AP]].

Moreover, at the date this report was written, work is under way to release a new version of [[DCAT-AP]], aligned with [[VOCAB-DCAT-2]], which will eventually be reflected in the [[DCAT-AP]] extensions.

Data catalogs, data services, and datasets

The following table shows data catalogs, data services, and datasets providing implementation evidence of the revisions proposed in [[VOCAB-DCAT-2]].

The criteria used to select the relevant data catalogs are the following ones:

1. They implement [[VOCAB-DCAT-2]] or one of the vocabularies listed in .
2. Preferably, they have a broad geographic and/or community coverage.

As explained in , there are many data catalogs supporting [[DCAT-AP]] and its extensions. Among these, we have selected the European Data Portal, since it provides a single access point to data published in catalogs across Europe (at the date this report was written, the European Data Portal included nearly 1,000,000 metadata records), and Zenodo, which is the most used repository in Europe for scientific data (at the date this report was written, it included nearly 1,500,000 metadata records).

The rest of the selected data catalogs have been chosen because they support either [[VOCAB-DCAT-2]] or the other vocabularies listed in .

As already mentioned in , CKAN, a popular catalog platform on which also some of the data catalogs listed earlier are based, supports [[DCAT-AP]] via a specific extension, and therefore it has not been included here.

Finally, among other reported implementations, it is worth mentioning the LinkedPipes DCAT-AP Viewer and the LinkedPipes DCAT-AP Forms, where support to [[VOCAB-DCAT-2]] is being implemented at the date this report was written.

Guidelines and reports

The following table lists guidelines and reports that demonstrate actual implementations of the revisions proposed in [[VOCAB-DCAT-2]]. These examples are drawn from the data catalogs and DCAT-based vocabularies listed in the previous sections.