DCAT-AP for Base Registries (BRegDCAT-AP)

Introduction

Context

One of the targets of the Digital Single Market [[EU-DIGI-STRAT]] is to deliver cross-border and crosssector public services in Europe. Thus, in order to succeed with this objective, Member States’ base registries need to be interconnected. Base registries are trusted and reliable sources of basic information on data items such as citizens, corporations, vehicles, driver licences, buildings, and locations. They are the cornerstone of public services and essential entities for public administration management.

The interoperability of base registries is key for the development of the EU Single Digital Gateway (or just Gateway) [[SDG]], a platform that aims to be the single point of access to public EU Member States’ services, facilitating digital public services among public administrations and citizens. The implementation of the Gateway [[OOTS]] relies on the once-only principle, ensuring data that is submitted at least once to an EU Member State, could be reused by any public authority across the EU.

To interconnect European base registries it is of interest to have a European wide insight in the connection potential of these. The development of a European Registry of Base Registries (ERBR), a pan-European registry of base registries, will improve the interoperability of individual base registries and harmonise the existing registries of base registries, enabling a one-stop-platform for citizens, business and public bodies to access and manage base registries across the European Union and across different domains.

This specification, BRegDCAT-AP, facilitates the creation of ERBR. It interconnects public services with base registries and their associated services. By conforming to this specification Base Registries will becomes easier to find. And subsequently together with the provision through the Once Only Hub [[OOTS]] make them more interoperable by . This set of recommendations will enable a mechanism for the update of EU reducing technical, organisational and multilingual barriers.

Scope

This document provides the guidelines on how to use DCAT-AP to make Base Registries well documented. The document is called the "usage guidelines of DCAT-AP for Base Registries", in short BRegDCAT-AP.

To understand these guidelines, it is important to realise that the BRegDCAT-AP applies to a subset of all the datasets that are collected by (Open) Data Portals in Europe. A single catalogue may contain catalogued resources which are within and outside scope of BRegDCAT-AP.

Conformance Statement

In order for applications to conform to BregDCAT-AP, it MUST conform to DCAT-AP. In addition, the application must conform to the mentioned constraints and usage guidelines following similar conformance statements as specifief in DCAT-AP.

Provider requirements

In order to conform to this Annex to the Application Profile of DCAT-AP, an application that provides metadata MUST:

Provide a description of the Catalogue, including at least the mandatory properties specified for the class Catalogue.
Provide descriptions of Datasets in the Catalogue, including at least the mandatory properties for the class Dataset.
Provide descriptions of Distributions, if any, of Datasets in the Catalogue, including at least the mandatory properties for the class Distribution.
Provide descriptions of Data Services, if any, in the Catalogue, including at least the mandatory properties for the class Data Service.
Provide descriptions of all other classes such as Agents, Contact Points, Licences, etc.

Receiver requirements

In order to conform to this Annex to the Application Profile, an application that receives metadata MUST be able to:

Process information for all classes and properties specified in section [[[#quick-reference]]].

"Processing" means that receivers must accept incoming data and transparently provide these data to applications and services. It does neither imply nor prescribe what applications and services finally do with the data (parse, convert, store, make searchable, display to users, etc.).

Terminology

An Application Profile is a specification that reuses terms from one or more base standards, adding more specificity by identifying mandatory, recommended and optional elements to be used for a particular application, as well as recommendations for controlled vocabularies to be used.

An Annex to an Application Profile is a specification that precises the use of some aspects of the Application Profile for a specific context.

A Base Registry is a web-based system that contains an inventory of descriptions of Master datasets and provides services enabling discovery and re-use of the datasets. The mandate of a Base Registry is given by specific legislation.

At EU level, National Registers aggregate information about Base Registries in Registries of Base Registries. A Registry of Base Registries is considered as a Catalogue of collections of metadata about datasets or data services.

This specification uses the following prefixes to shorten the URIs for readibility.

Prefix	Namespace IRI
`adms`	`http://www.w3.org/ns/adms#`
`cpsv`	`http://purl.org/vocab/cpsv#`
`dcat`	`http://www.w3.org/ns/dcat#`
`dcatap`	`http://data.europa.eu/r5r/`
`dct`	`http://purl.org/dc/terms/`
`dctype`	`http://purl.org/dc/dcmitype/`
`eli`	`http://data.europa.eu/eli/ontology#`
`foaf`	`http://xmlns.com/foaf/0.1/`
`locn`	`http://www.w3.org/ns/locn#`
`owl`	`http://www.w3.org/2002/07/owl#`
`rdf`	`http://www.w3.org/1999/02/22-rdf-syntax-ns#`
`rdfs`	`http://www.w3.org/2000/01/rdf-schema#`
`skos`	`http://www.w3.org/2004/02/skos/core#`
`vcard`	`http://www.w3.org/2006/vcard/ns#`
`xsd`	`http://www.w3.org/2001/XMLSchema#`

Overview

BRegDCAT-AP is an annex to DCAT-AP. It describes additional usage of the DCAT-AP for Base Registries. In this document only the additional information, that is required for the catalogued resources which are within scope of the regulation, is included. In any other case, the guidelines of DCAT-AP itself are applicable.

As shown in the profile diagram below: the sole addition to DCAT-AP is the relationship with a public service. As such the Annex can be even further reduced to a simple case of relating a public service with a catalogued resource.

Application profile diagram

An overview of BRegDCAT-AP is shown by the UML diagram below. The UML diagram illustrates the specification described in this document. For readability purposes the representation has been condensed as follows:

The figure contains the key classes with some important supporting classes. Other object properties (relationships) are listed as properties on the UML class with their target range.
The class dcat:Resource has been included more easily see the connection with W3C DCAT. DCAT-AP treats it as an abstract notion.

The cardinalities and qualifications are included in the figure.

For readibility of this document as an annex to DCAT-AP, the core relationships between classes are included.

Main Entities

The main entities are those that form the core of the Application Profile.

Catalogue

Definition: A catalogue or repository that hosts the Datasets or Data Services being described.
Reference in DCAT: Link
Properties: For this entity the following properties are defined: dataset , record , service .

Property	Range	Card	Definition	Usage	DCAT
dataset	Dataset	0..*	A Dataset that is part of the Catalogue.	As empty Catalogues are usually indications of problems, this property should be combined with the next property service to implement an empty Catalogue check.	Link
record	Catalogue Record	0..*	A Catalogue Record that is part of the Catalogue.		Link
service	Data Service	0..*	A site or end-point (Data Service) that is listed in the Catalogue.	As empty Catalogues are usually indications of problems, this property should be combined with the previous property dataset to implement an empty Catalogue check.	Link

Catalogue Record

Definition: A description of a Dataset's entry in the Catalogue.
Reference in DCAT: Link
Properties: For this entity the following properties are defined: primary topic .

	Property	Range	Card	Definition	Usage	DCAT
	primary topic	Catalogued Resource	1	A link to the Dataset, Data service or Catalog described in the record.	A catalogue record will refer to one entity in a catalogue. This can be either a Dataset or a Data Service. To ensure an unambigous reading of the cardinality the range is set to Catalogued Resource. However it is not the intend with this range to require the explicit use of the class Catalogued Record. As abstract class, an subclass should be used.	Link

Catalogued Resource

Definition: Resource published or curated by a single agent.
Reference in DCAT: Link
Usage Note: For DCAT-AP, the class is considered an abstract notion.
Properties: This specification does not impose any additional requirements to properties for this entity.

Data Service

Definition: A collection of operations that provides access to one or more datasets or data processing functions.
Reference in DCAT: Link
Subclass of
: Catalogued Resource
Properties: For this entity the following properties are defined: serves dataset .

	Property	Range	Card	Definition	Usage	DCAT
	serves dataset	Dataset	0..*	This property refers to a collection of data that this data service can distribute.		Link

Dataset

Definition: A conceptual entity that represents the information published.
Reference in DCAT: Link
Subclass of
: Catalogued Resource
Properties: For this entity the following properties are defined: dataset distribution .

	Property	Range	Card	Definition	Usage	DCAT
	dataset distribution	Distribution	0..*	An available Distribution for the Dataset.		Link

Distribution

Definition: A physical embodiment of the Dataset in a particular format.
Reference in DCAT: Link
Usage Note: Bulk downloads should be encoded as a Distribution.
Properties: For this entity the following properties are defined: access service .

	Property	Range	Card	Definition	Usage	DCAT
	access service	Data Service	0..*	A data service that gives access to the distribution of the dataset.		Link

Public Registry Service

Definition: A Registry Service is a public service that creates, maintains and/or manages Base Registries or a Registry of Base Registries. This service, provided by public administrations, or by other organisations on their behalf, stores and provides basic information on authoritative data items such as people, companies, vehicles, licences, buildings, locations and roads.
Properties: For this entity the following properties are defined: produces .

	Property	Range	Card	Definition	Usage	DCAT
	produces	Catalogued Resource	0..*	This property defines the output of the service as a data resource available and managed by a Base Registry Service.	The output must be also described as a dcat:Catalog, a dcat:Dataset or a dcat:DataService.

Supportive Entities

The supportive entities are supporting the main entities in the Application Profile. They are included in the Application Profile because they form the range of properties.

Concept

Definition: A concept can be viewed as an idea or notion; a unit of thought. However, what constitutes a unit of thought is subjective, and this definition is meant to be suggestive, rather than restrictive.
Properties: This specification does not impose any additional requirements to properties for this entity.

Legal Resource

Definition: This class represents the legislation, policy or policies that lie behind the Rules that govern the service.
Usage Note: The definition and properties of the Legal Resource class are aligned with the ontology included in "Council conclusions inviting the introduction of the European Legislation Identifier (ELI)". For describing the attributes of a Legal Resource (labels, preferred labels, alternative labels, definition, etc.) we refer to the ELI ontology. In this data specification the use is restricted to instances of this class that follow the ELI URI guidelines.
Properties: This specification does not impose any additional requirements to properties for this entity.

Literal

Definition: A literal value such as a string or integer; Literals may be typed, e.g. as a date according to xsd:date. Literals that contain human-readable text have an optional language tag as defined by BCP 4715.
Properties: This specification does not impose any additional requirements to properties for this entity.

Resource

Definition: Anything described by RDF.
Properties: This specification does not impose any additional requirements to properties for this entity.

Quick Reference of Classes and Properties

This section provides a condensed tabular overview of the mentioned classes and properties in this specification. The properties are grouped under headings mandatory, recommended, optional and deprecated. These terms have the following meaning.

Mandatory property: a receiver MUST be able to process the information for that property; a sender MUST provide the information for that property.
Recommended property: a receiver MUST be able to process the information for that property; a sender SHOULD provide the information for that property if it is available.
Optional property: a receiver MUST be able to process the information for that property; a sender MAY provide the information for that property but is not obliged to do so.
Deprecated property: a receiver SHOULD be able to process information about instances of that property; a sender SHOULD NOT provide the information about instances of that property.

Class	Class IRI	Property Type	Property	Property IRI
Catalogue	http://www.w3.org/ns/dcat#Catalog	Recommended	dataset	http://www.w3.org/ns/dcat#dataset
Catalogue	http://www.w3.org/ns/dcat#Catalog	Recommended	service	http://www.w3.org/ns/dcat#service
Catalogue	http://www.w3.org/ns/dcat#Catalog	Optional	record	http://www.w3.org/ns/dcat#record
Catalogue Record	http://www.w3.org/ns/dcat#CatalogRecord	Mandatory	primary topic	http://xmlns.com/foaf/0.1/primaryTopic
Catalogued Resource	http://www.w3.org/ns/dcat#Resource
Concept	http://www.w3.org/2004/02/skos/core#Concept
Data Service	http://www.w3.org/ns/dcat#DataService	Recommended	serves dataset	http://www.w3.org/ns/dcat#servesDataset
Dataset	http://www.w3.org/ns/dcat#Dataset	Recommended	dataset distribution	http://www.w3.org/ns/dcat#distribution
Distribution	http://www.w3.org/ns/dcat#Distribution	Optional	access service	http://www.w3.org/ns/dcat#accessService
Legal Resource	http://data.europa.eu/eli/ontology#LegalResource
Literal	http://www.w3.org/2000/01/rdf-schema#Literal
Public Registry Service	http://purl.org/vocab/cpsv#PublicService	Optional	produces	http://purl.org/vocab/cpsv#produces
Resource	http://www.w3.org/2000/01/rdf-schema#Resource

Acknowledgments

The editors gratefully acknowledge the contributions made to this document by all members of the working group. This work was elaborated by a Working Group under SEMIC by Interoperable Europe. Interoperable Europe of the European Commission was represented by Pavlina Fragkou and Seth Van Hooland. Natasa Sofou, Makx Dekkers and Bert Van Nuffelen were the editors of the specification. Past and current contributors are : Alberto Abella , Anssi Ahlberg , Adam Arndt , Judie Attard , Julius Belickas , Nick Berkvens , Konstantis Bogucarskis , Peter Bruhn Andersen , Ewa Bukala , Martin Böhm , Nikolai Bülow Tronche , Ana Cano , Eileen Carroll , Egle Cepaitiene , Luisa Cidoncha , Marco Combetto , John Cunningham , Jitse De Cock , Ine de Visser , Kelly Deirdre , Makx Dekkers , Radko Domanska , Iwona Domaszewska , Ulrika Domellöf Mattsson , Alessio Dragoni , Nicolai Draslov , Frederik Emanualsson , Jordi Escriu , Jose-Luis Fernandez-Villacanas , Nuno Freire , Leyre Garralda , Alma Gonzalez , Capser Gras , Bart Hanssens , Kieran Harper , Jasper Heide , Mika Honkanen , Peter Isrealsson , Fabian Kirstein , Michal Kitta , Jakub Klimek , Rae Knowler , Fredrik Knutsson , Peter Kochman , Sirkku Kokkola , Michal Kuban , Michal Kuban , Kaia Kulla , Maria Lenartowicz , Anja Litka , Anja Loddenkemper , Hagar Lowenthal , Melanie Mageean , Agata Majchrowska , Hugh Mangan , Estelle Maudet , Balint Miklos , Esther Minguela , Joachim Nielandt , Geraldine Nolf , Erik Obsteiner , Javier Orozco , Csapo Orsolya , Matthias Palmer , Alberto Palomo , Francesco Paolicelli , Eirini Pappi , Mihai Paunescu , Sylwia Pichlak Pawlak , Jiri Pilar , Ludger Rinsche , Daniele Rizzi , Reet Roosalu , Ana Rosa , Maik Roth , Antonio Rotundo , Michal Ruzicka , Jill Saligoe-Simmel , Fabian Santi , Giovanna Scaglione , Giampaolo Selitto , Martin Semberger , Paulo Seromenho , Jan Skornsek , Michele Spichtig , Emidio Stani , Kjersti Steien , Simon Steuer , Terje Sylvarnes , Martin Traunmuller , Kees Trautwein , Stavros Tsouderos , Thomas Tursics , Bert Van Nuffelen , Uwe Voges , Gabriella Wiersma , Jesper Zedlitz , Mantas Zimnickas .