DCAT-AP-DONL 1.1

The DCAT application profile for data.overheid.nl.

Summary

This documentation describes the DCAT application profile named DCAT-AP-DONL 1.1. This is a metadata standard based on the DCAT application profile DCAT-AP-NL 1.1. The application profile aims to reduce data duplication and to standardize values of properties wherever possible, this to improve its usefulness for linked data applications.

DCAT-AP-DONL 1.1 is the DCAT application profile used by Data.Overheid.nl, which is the dataset portal of the Dutch government. It is also implemented as a CKAN extension which is available to the public on the Textinfo Gitlab server.

This documentation provides the exact details of the application profile and explains in what way it deviates from DCAT-AP-NL 1.1 and DCAT-AP-DONL 1.0 (its previous version).

Contact

For questions or comments regarding this DCAT application profile please contact KOOP at:

Online:koopoverheid.nl
Email:opendata@overheid.nl
Telephone:(070) 7000 526

Changelog

The following changes have been applied over time to the standard and/or its documentation.

03/07/2019

  • Introduced a new property for the Dataset class: nationalCoverage. This property is an optional boolean. When this property is not present in a dataset it is considered ‘false’.

12/11/2018

  • The property keyword was incorrectly listed as mandatory. It has been updated to accurately describe its recommended status

05/11/2018

  • The downloadURL property of a Distribution was incorrectly listed as having a 1..n cardinality, this has been corrected to 0..n to accurately reflect its recommended state.
  • Further clarified the Period class. this class consists of only recommended properties but has additional rules which state that at least one of these properties should be present. An empty Period class is considered invalid.
  • Introduced three new properties for the Dataset class, highValue, basisRegister and referentieData. These new properties are optional boolean properties. When these properties are not present in a dataset they are considered ‘false’.
  • The property rights of Distribution was incorrectly listed as mandatory, this property is recommended. Its state and cardinality have been corrected.

Classes

DCAT-AP-DONL 1.1 is based on the DCAT-AP-NL 1.1 standard. As such it inherits all the specifications from said standard. DCAT-AP-DONL 1.1 does modify the classes ‘Dataset’ and ‘Distribution’. The specifications of the DCAT-AP-DONL versions of these classes will now be handled. Given the fact that DCAT-AP-DONL must remain compatible with DCAT-AP-NL and by extension DCAT-AP-EU, these changes will not be groundbreaking.

In the schemas of the classes a column exists named ‘Man.’. This details whether a property is Mandatory (man), Recommended (rec) or Optional (opt).

There are direct references in the schemas below to the classes Period, LegalFoundation and Checksum , for the sake of clarity these are included in this documentation, however, these are direct copies of their counterparts in the DCAT-AP-NL standard.

Dataset

The properties and their acceptable values are outlined below:

Property Man. Card. URI Value
identifier man 1..1 dct:identifier xsd:anyURI
title man 1..1 dct:title xml:string
description man 1..1 dct:description xml:string
keyword rec 0..n dcat:keyword xml:string
metadataLanguage man 1..1 dct:language donl:language
language man 1..n dct:language donl:language
theme man 1..n dcat:theme overheid:taxonomiebeleidsagenda
modificationDate man 1..1 dct:modified xsd:date (ISO 8601)
authority man 1..1 overheid:authority donl:authority
publisher man 1..1 dct:publisher donl:authority
contactPoint man 1..1 dcat:contactPoint vcard:Kind
accessRights rec 0..1 dct:accessRights overheid:openbaarheidsniveau
datasetStatus rec 0..1 adms:status overheid:datasetStatus
landingPage rec 0..1 dcat:landingPage xsd:anyURI
spatial rec 0..n dct:spatial overheid:spatial
temporal rec 0..1 dct:temporal class Period
conformsTo rec 0..n dct:conformsTo xsd:anyURI
alternativeIdentifier rec 0..n adms:identifier xsd:anyURI
relatedResource rec 0..n dct:relation xsd:anyURI
source rec 0..n dct:source xsd:anyURI
hasVersion rec 0..n dct:hasVersion xsd:anyURI
isVersionOf rec 0..n dct:isVersionOf xsd:anyURI
releaseDate rec 0..1 dct:issued xsd:date (ISO 8601)
version rec 0..1 owl:versionInfo xml:string
versionNotes rec 0..n adms:versionNotes xml:string
legalFoundation rec 0..1 overheid:grondslag class LegalFoundation
datePlanned opt 0..1 skos:concept xsd:date (ISO 8601)
documentation opt 0..n foaf:page xsd:anyURI
frequency opt 0..1 dct:accrualPeriodicity overheid:frequency
provenance opt 0..n dct:provenance xsd:anyURI
sample opt 0..n adms:sample xsd:anyURI
highValue rec 0..1 skos:concept xsd:boolean
basisRegister rec 0..1 skos:concept xsd:boolean
referentieData rec 0..1 skos:concept xsd:boolean
nationalCoverage rec 0..1 skos:concept xsd:boolean

Distribution

The properties and their acceptable values are outlined below:

Property Man. Card. URI Value
accessURL man 1..1 dcat:accessURL xsd:anyURI
license man 1..1 dct:license overheid:license
title man 1..1 dct:title xml:string
description man 1..1 dct:description xml:string
language man 1..n dct:language donl:language
format man 1..1 dct:format mdr:filetype
rights rec 0..1 dct:rights xml:string
status rec 0..1 adms:status adms:distributiestatus
releaseDate rec 0..1 dct:issued xsd:date (ISO 8601)
modificationDate rec 0..1 dct:modified xsd:date (ISO 8601)
byteSize rec 0..1 dcat:byteSize xml:number
downloadURL rec 0..n dcat:downloadURL xsd:anyURI
mediaType rec 0..1 dcat:mediaType iana:mediatype
linkedSchemas rec 0..n dct:conformsTo xsd:anyURI
checksum opt 0..1 spdc:checksum class Checksum
documentation opt 0..n foaf:page xsd:anyURI

Period

The properties and their acceptable values are outlined below:

Property Man. Card. URI Value
label rec 0..1 skos:concept xml:string
startDate rec 0..1 schema:startDate xsd:date (ISO 8601)
endDate rec 0..1 schema:endDate xsd:date (ISO 8601)

As stated, the Period class consists of only recommended properties. However, when providing a Period for your dataset atleast one of these recommended properties must be provided. An empty Period class is considered invalid.

LegalFoundation

The properties and their acceptable values are outlined below:

Property Man. Card. URI Value
ref man 1..1 overheid:juriconnectverwijzing xml:string
label man 1..1 overheid:linktekst xml:string
uri man 1..1 foaf:page xsd:anyURI

Checksum

The properties and their acceptable values are outlined below:

Property Man. Card. URI Value
hash man 1..1 skos:concept xml:string
algorithm man 1..1 skos:concept xml:string

All other classes of the DCAT-AP-DONL standard are fully inherited from the DCAT-AP-NL standard.

Changes

Changes from the related DCAT application profiles will be listed and motivated.

Changes from the DCAT-AP-DONL 1.0 standard

The changes from DCAT-AP-DONL 1.0 to DCAT-AP-DONL 1.1 are listed below.

Note

DCAT-AP-DONL 1.0 was surprisingly poorly documented, given this, the list below may not be fully accurate. This changelog is based on 2015-04-17 Mapping Modellen_0.xslx.

New properties

The following properties have been introduced

Note

Most of the new properties are due to changes in the parent standard DCAT-AP-NL 1.1. These hanges will be listed, but not motivated.

Dataset:metadataLanguage
This new mandatory property forces providers to clarify which language is used in the metadata of a Dataset.
Dataset:alternativeIdentifier
From DCAT-AP-NL 1.1
Dataset:relatedResource
From DCAT-AP-NL 1.1
Dataset:source
From DCAT-AP-NL 1.1
Dataset:hasVersion
From DCAT-AP-NL 1.1
Dataset:isVersionOf
From DCAT-AP-NL 1.1
Dataset:documentation
From DCAT-AP-NL 1.1
Dataset:provenance
From DCAT-AP-NL 1.1
Dataset:sample
From DCAT-AP-NL 1.1
Distribution:metadataLanguage
This new mandatory property forces providers to clarify which language is used in the metadata of a Distribution.
Distribution:license
From DCAT-AP-NL 1.1
Distribution:language
From DCAT-AP-NL 1.1
Distribution:rights
From DCAT-AP-NL 1.1
Distribution:linkedSchemas
From DCAT-AP-NL 1.1
Distribution:checksum
From DCAT-AP-NL 1.1
Distribution:documentation
From DCAT-AP-NL 1.1

Changed properties

Changes have been made to every property of DCAT-AP-DONL 1.0. See the new class definitions for the new version of the classes. The most important conceptual changes are detailed and motivated below

Standardization of values
In order to combat the fifty different spellings of ‘Gemeente Nijmegen’ and the likes, most property ranges have been limited to a certain list of acceptable values. These lists of values contain URIs that reference resources that have acceptable values for the given property, e.g. http://standaarden.overheid.nl/owms/terms/Nijmegen_(gemeente).
Promoting linked data
Most property ranges have been limited from xml:string to xsd:anyURI. Data.Overheid.nl prefers resolvable URIs from a linked data perspective.

Removed properties

The following properties have been removed

Note

Most of the removed properties are due to changes in the parent standard DCAT-AP-NL 1.1. These changes will be listed, but not motivated.

Dataset:LODStars
From DCAT-AP-NL 1.1
Dataset:doel
From DCAT-AP-NL 1.1
Dataset:kwaliteit
From DCAT-AP-NL 1.1

Changes from the DCAT-AP-NL 1.1 standard

The changes from DCAT-AP-NL 1.1 to DCAT-AP-DONL 1.1 are listed below.

New properties

The following properties have been introduced

Dataset:datasetStatus
This recommended property defines in which part of a lifecycle a dataset exists. A dataset can be available, planned unavailable or being researched. Use Dataset:datePlanned to indicate when a dataset is expected to receive the datasetStatus available.
Dataset:datePlanned
This optional property defines the planned date at which this dataset becomes available. It is closely related to the datasetStatus planned, unavailable and being researched.
Dataset:license
This new, mandatory, property was introduced for the Dataset class. It allows a license to apply to a dataset, rather than a Distribution, which already had the license property.
Dataset:metadataLanguage
This new mandatory property forces providers to clarify which language is used in the metadata of a Dataset.
Distribution:metadataLanguage
This new mandatory property forces providers to clarify which language is used in the metadata of a Distribution.

Changed properties

The following properties have been modified

Dataset:title
The cardinality has been changed from 1..n to 1..1. Data.Overheid.nl demands that metadata is provided in only one language, therefore there is no longer any need to support multiple titles for one dataset.
Dataset:description
The cardinality has been changed from 1..n to 1..1. Data.Overheid.nl demands that metadata is provided in only one language, therefore there is no longer any need to support multiple descriptions for one dataset.
Dataset:theme
This property was changed from Recommended to Mandatory. Data.Overheid.nl requires at least one theme to properly categorize datasets. Because of this, its cardinality is changed from 0..n to 1..n.
Dataset:authority
This property was changed from Recommended to Mandatory. It must always be clear who owns the dataset, therefore this property needs to be mandatory. Because of this, its cardinality is changed from 0..1 to 1..1.
Dataset:publisher
This property was changed from Recommended to Mandatory. It must always be clear who published the dataset, therefore this property needs to be mandatory. Because of this, its cardinality is changed from 0..1 to 1..1.
Dataset:contactPoint
This property was changed from Recommended to Mandatory. A published dataset needs to have a contactPoint so that questions and/or comments regarding a dataset have a place to go. Because of this, its cardinality is changed from 0..n to 1..1.
Dataset:conformsTo
This property was changed from Optional to Recommended. Data.Overheid.nl wants as much metadata about a dataset as possible. This is purely a semantic change to inspire providers to provide more metadata. Furthermore, its range was narrowed to xsd:anyURI. Data.Overheid.nl prefers resolvable URIs from a linked data perspective.
Dataset:alternativeIdentifier
This property was changed from Optional to Recommended. The alternativeIdentifier is important in the quest to minimise duplicate datasets. As such this property now has a higher classification to signify this.
Dataset:relatedResource
This property was changed from Optional to Recommended. Data.Overheid.nl wants as much metadata about a dataset as possible. This is purely a semantic change to inspire providers to provide more metadata. Furthermore, its range was narrowed to xsd:anyURI. Data.Overheid.nl prefers resolvable URIs from a linked data perspective.
Dataset:source
This property was changed from Optional to Recommended. Data.Overheid.nl wants as much metadata about a dataset as possible. This is purely a semantic change to inspire providers to provide more metadata. Furthermore, its range was narrowed to xsd:anyURI. Data.Overheid.nl prefers resolvable URIs from a linked data perspective.
Dataset:hasVersion
This property was changed from Optional to Recommended. Data.Overheid.nl wants as much metadata about a dataset as possible. This is purely a semantic change to inspire providers to provide more metadata. Furthermore, its range was narrowed to xsd:anyURI. Data.Overheid.nl prefers resolvable URIs from a linked data perspective.
Dataset:isVersionOf
This property was changed from Optional to Recommended. Data.Overheid.nl wants as much metadata about a dataset as possible. This is purely a semantic change to inspire providers to provide more metadata. Furthermore, its range was narrowed to xsd:anyURI. Data.Overheid.nl prefers resolvable URIs from a linked data perspective.
Dataset:releaseDate
This property was changed from Optional to Recommended. Data.Overheid.nl wants as much metadata about a dataset as possible. This is purely a semantic change to inspire providers to provide more metadata.
Dataset:version
This property was changed from Optional to Recommended. Data.Overheid.nl wants as much metadata about a dataset as possible. This is purely a semantic change to inspire providers to provide more metadata.
Dataset:version_notes
This property was changed from Optional to Recommended. Data.Overheid.nl wants as much metadata about a dataset as possible. This is purely a semantic change to inspire providers to provide more metadata.
Distribution:license
This property was changed from Recommended to Mandatory. Data.Overheid.nl requires that all distributions have a license property. It must always be clear what license applies to a distribution. Because of this, its cardinality is changed from 0..1 to 1..1.
Distribution:title
The cardinality has been changed from 1..n to 1..1. Data.Overheid.nl demands that metadata is provided in only one language, therefore there is no longer any need to support multiple titles for one distribution.
Distribution:description
The cardinality has been changed from 1..n to 1..1. Data.Overheid.nl demands that metadata is provided in only one language, therefore there is no longer any need to support multiple titles for one distribution.
Distribution:format
This property was changed from Recommended to Mandatory. A Distribution always has a format, as such, it should be provided. Because of this, its cardinality is changed from 0..1 to 1..1.
Distribution:byteSize
This property was changed from Optional to Recommended. Data.Overheid.nl wants as much metadata about a distributions as possible. This is purely a semantic change to inspire providers to provide more metadata.
Distribution:downloadURL
This property was changed from Optional to Recommended. Data.Overheid.nl wants as much metadata about a distributions as possible. This is purely a semantic change to inspire providers to provide more metadata.
Distribution:mediaType
This property was changed from Optional to Recommended. Data.Overheid.nl wants as much metadata about a distributions as possible. This is purely a semantic change to inspire providers to provide more metadata.
Distribution:releaseDate
This property was changed from Optional to Recommended. Data.Overheid.nl wants as much metadata about a distributions as possible. This is purely a semantic change to inspire providers to provide more metadata.
Distribution:rights
This property was changed from optional to Mandatory. Rights always apply to Distributions, therefore providers must dictate which rights apply to the Distribution. Because of this, its cardinality is changed from 0..1 to 1..1.
Distribution:status
This property was changed from Optional to Recommended. Data.Overheid.nl wants as much metadata about a distributions as possible. This is purely a semantic change to inspire providers to provide more metadata.
Distribution:modificationDate
This property was changed from Optional to Recommended. Data.Overheid.nl wants as much metadata about a distributions as possible. This is purely a semantic change to inspire providers to provide more metadata.
Distribution:linkedSchemas
This property was changed from Optional to Recommended. Data.Overheid.nl wants as much metadata about a distributions as possible. Furthermore its range has been narrowed to only allow valid URIs. Data.Overheid.nl prefers resolvable URIs from a linked data perspective.

Removed properties

The following properties have been removed

None
No properties have been removed that were part of the DCAT-AP-NL 1.1 standard.

Workflow

Two aspects of the DCAT-AP-DONL 1.1 application profile deserve further elaboration, as they are a considerable change from either DCAT-AP-DONL 1.0 or DCAT-AP-NL 1.1. This is done below.

Dataset identifier

The value of a dataset identifier is the original identifier of the dataset. This value must be preserved when this dataset moves across dataportals. This ensures that the dataset, regardless of the dataportal it currently resides in, can always be uniquely identified. To communicate that a dataset is or has been present in a dataportal, the dataportal may elect to include its own internal identifier of the dataset as a part of the alternativeIdentifier property.

This process is visualised below:

Workflow identifier with multiple dataportals

Identifier workflow visualised

In the event that changes are made to a dataset that are not made by the original authority or publisher, the identifier property is invalidated. At this point the value of the identifier property is the identifier of the dataset that that dataportal currently maintains. In the above example, should NGR make changes to the dataset, then the internal identifier that NGR maintains for the dataset becomes the identifier of the new dataset.

Multilingual support

DCAT-AP-DONL mandates that the metadata of a dataset is provided in only one language. In order to provide metadata in multiple languages for a single dataset, the following steps must be taken.

First create the original dataset with metadata in a specific language:

{
    "identifier":         "http://mydata.portal.com/dataset/mijndataset1",
    "metadata_langugage": "http://publications.europa.eu/resource/authority/language/NLD",
    "title":              "Mijn dataset titel 1",
    "description":        "Mijn dataset omschrijving 1",
    ...
}

Then, when wanting to support metadata in a secondary language, create a new dataset with the metadata in the new language which references the original dataset:

{
    "identifier":         "http://mydata.portal.com/dataset/mijndataset1",
    "metadata_langugage": "http://publications.europa.eu/resource/authority/language/ENG",
    "title":              "My dataset 1",
    "description":        "My dataset description 1",
    "is_version_of":      "https://data.overheid.nl/datasets/mijndataset1",
    ...
}

By declaring your dataset with the same identifier and stating that the new dataset is a version of the original dataset you signal that the datasets are identical and that only the metadata is different. Ensure that the different datasets have unique metadataLanguage properties.

A visual guide:

Visualisation of multilingual support in DCAT-AP-DONL

Visualisation of multilingual support in DCAT-AP-DONL

In short: group all the resources with metadata in the same language under one dataset, which metadataLanguage matches that of the resources. When the dataset becomes available in a new language , create and maintain a separate dataset and resources for the new language. The actual accessURLs and downloadURLs can be the same across both datasets.

Valuelists

The DCAT-AP-DONL 1.1 standard uses lists of acceptable values in order to standardize the values of properties wherever possible. These lists are mostly inherited from the parent standard DCAT-AP-NL 1.1. These lists are shown below.

These valuelists are published on waardelijsten.dcat-ap-donl.nl.

Name Location
adms:changetype http://waardelijsten.dcat-ap-donl.nl/adms_changetype.json
adms:distributiestatus http://waardelijsten.dcat-ap-donl.nl/adms_distributiestatus.json
donl:catalogs http://waardelijsten.dcat-ap-donl.nl/donl_catalogs.json
donl:language http://waardelijsten.dcat-ap-donl.nl/donl_language.json
donl:organization http://waardelijsten.dcat-ap-donl.nl/donl_organization.json
iana:mediatypes http://waardelijsten.dcat-ap-donl.nl/iana_mediatypes.json
mdr:filetype_nal http://waardelijsten.dcat-ap-donl.nl/mdr_filetype_nal.json
overheid:dataset_status http://waardelijsten.dcat-ap-donl.nl/overheid_dataset_status.json
overheid:frequency http://waardelijsten.dcat-ap-donl.nl/overheid_frequency.json
overheid:license http://waardelijsten.dcat-ap-donl.nl/overheid_license.json
overheid:openbaarheidsniveau http://waardelijsten.dcat-ap-donl.nl/overheid_openbaarheidsniveau.json
overheid:spatial_gemeente http://waardelijsten.dcat-ap-donl.nl/overheid_spatial_gemeente.json
overheid:spatial_koninkrijksdeel http://waardelijsten.dcat-ap-donl.nl/overheid_spatial_koninkrijksdeel.json
overheid:spatial_provincie http://waardelijsten.dcat-ap-donl.nl/overheid_spatial_provincie.json
overheid:spatial_scheme http://waardelijsten.dcat-ap-donl.nl/overheid_spatial_scheme.json
overheid:spatial_waterschap http://waardelijsten.dcat-ap-donl.nl/overheid_spatial_waterschap.json
overheid:taxonomiebeleidsagenda http://waardelijsten.dcat-ap-donl.nl/overheid_taxonomiebeleidsagenda.json

DCAT-AP-DONL 1.1 maintains its own valuelists rather than simply using the DCAT-AP-NL valuelists. The primary motivater behind this decision is that DCAT-AP-DONL may elect not to support certain values of the DCAT-AP-NL valuelists. In order to support this feature, DCAT-AP-DONL has to maintain its own valuelists. An example of such a usecase is where DCAT-AP-DONL may decide not to support a certain license that DCAT-AP-NL supports.

Implementation

The DCAT-AP-DONL 1.1 metadata standard has been implemented in a CKAN extension. This extension allows your CKAN installation to manage datasets and distributions according to the standards defined in this documentation.

This extension, called ckanext-dcatdonl, can be found online at:

Repository:gitlab.textinfo.nl/opensource/ckanext-dcatdonl/.
Documentation:ckanext-dcatdonl.readthedocs.io