ADMS is a profile of DCAT, used to describe semantic assets, defined as highly reusable metadata (e.g. xml schemata, generic data models) and reference data (e.g. code lists, taxonomies, dictionaries, vocabularies) that are used for eGovernment system development.

ADMS was first developed by PwC EU Services and published by the European Commission. Further development and review has been undertaken by the Government Linked Data Working Group (GLD WG).


ADMS, the Asset Description Metadata Schema, is a profile of DCAT [[DCAT]] for describing so-called Semantic Assets, that is, things like standards, code lists and taxonomies. Someone searching for a Semantic Asset is likely to have different needs, priorities and expectations than someone searching for a data set in a data catalog and these differences are reflected in ADMS. In particular, users seeking a Semantic Asset are likely to be searching for 'a document' — something they can open and read using familiar desktop software, as opposed to something that needs to be processed. Of course this is a very broad generalization. If a code list is published as a SKOS Concept scheme then it is both a Semantic Asset and a dataset and it can be argued that all Semantic Assets are datasets. Therefore the difference in user expectation is at the heart of what distinguishes ADMS as a profile of DCAT. A further distinction between DCAT anad ADMS can be made in that DCAT is designed to facilitate interoperability between data catalogs, i.e. the catalog itself is at the heart of the vocabulary. ADMS is focused on assets within a catalog.

The original development of ADMS was carried out under the Interoperability Solutions for European Public Administrations (ISA Programme) of the European Commission (EC). Contributors included representatives of Member States of the European Union, operators of national repositories, standardization bodies and independent experts whose work was published in April 2012 [[ADMS1]]. That document includes the history and motivation behind the development of ADMS, as well as the business need and usage scenario for it.

This version of ADMS builds on that work in a broader, global context.

A data interchange, however that interchange occurs, is conformant with ADMS if:

A conforming data interchange:

An ADMS profile is a specification for data interchange that adds additional constraints. Such additional constraints in a profile may include (but are not limited to):

ADMS is technology-neutral and a publisher may use any of the terms defined in this document encoded in any technology although RDF and XML are preferred.


The namespace for ADMS is However, it should be noted that ADMS makes extensive use of terms from other vocabularies, in particular Dublin Core [[DC11]]. It re-uses and subclasses DCAT wherever possible and therefore defines a minimal set of classes and properties of its own. A full set of namespaces and prefixes used in this document is shown in the table below.



This document uses the following terminology:

Semantic interoperability is defined by the European Interoperability Framework 2.02 [[EIF2]] as the ability of information and communication technology (ICT) systems and the business processes they support to exchange data and to enable the sharing of information and knowledge: Semantic Interoperability enables systems to combine received information with other information resources and to process it in a meaningful manner. It aims at the mental representations that human beings have of the meaning of any given data.

The European Commission defines a semantic interoperability asset as highly reusable metadata (e.g. xml schemata, generic data models) and reference data (e.g. code lists, taxonomies, dictionaries, vocabularies) which is used for eGovernment system development [[TOGD]].

This definition is sufficiently broad to allow the inclusion of descriptions of various types of (meta)data to be included and managed in asset repositories. Possible types are for example specifications, guideline documents, metadata schemas, code lists, controlled vocabularies, and references to various types of entities in the real world, such as organizations, people and places.

Vocabulary Overview

ADMS is intended as a model that facilitates federation and co-operation. Like DCAT, ADMS has the concepts of a repository (catalog), assets within the repository that are often conceptual in nature, and accessible realizations of those assets, known as distributions. An asset may have zero or multiple distributions. As an example, a W3C namespace document can be considered to be a Semantic Asset that is typically available in multiple distributions, typically one or more machine processable versions and one in HTML for human consuption. An asset without any distributions is effectively a concept with no tangible realization, such as a planned output of a working group that has not yet been drafted.

ADMS is an RDF vocabulary with an RDF schema available at its namespace The original ADMS specification published by the European Commission [[ADMS1]] includes an XML schema that also defines all the controlled vocabularies and cardinality constraints associated with the original document.


This example provides a quick overview of how ADMS might be used to represent a Semantic Asset Repository and its assets.

Examples in this document are serialized in Turtle.

First, the repository description:

:Repository a adms:SemanticAssetRepository;
  dcterms:created "1947-02-07"^^xsd:date;
  dcterms:description "A complete catalog of code lists and standards created by the Exemplary Standards Body"@en;
  dcterms:publisher <>;
  dcterms:title "The Exemplary Standards Body Catalog"@en.

This assumes that the Exemplary Standards Body is described at

Next, a Semantic Asset. We'll create an imaginary code list called 'Fruit I like' for our example:

We might describe this Semantic Asset thus:

1  :Fruit_02 a adms:SemanticAsset;
2    dcterms:created "1999-05-24";
3    dcterms:description "Fruits that are found to be generally liked by most people.";
4    dcterms:publisher <>;
5    dcterms:title "Fruit I like"@en ;
6    adms:status <> ;
7    dcterms:type <> ;
8    xhv:previous :Fruit_01 ;
9    xhv:last :Fruit ;
10   adms:distribution :Fruit_02.csv ;
11   adms:distribution :Fruit_02.xml .

This provides the creation date (line 2), description (line 3), publisher (line 4) and a title (line 5) for the Semantic Asset. The status of the Semantic Asset is given in line 6 using one of the values made available in the original ADMS specification [[ADMS1]]. Likewise the type of Semantic Asset in line 7. In line 8 we can see that there was a previous version of this asset (Fruit_01) and that the latest version can be found by appending 'Fruit' to the data's root (line 9).

This Semantic Asset has two distributions linked in lines 11 and 12. One of these might be described thus:

:Fruit_02.xml a adms:SemanticAssetDistribution ;
  dcterms:description "XML encoding of Fruits that are found to be generally liked by most people.";
  dcterms:license <> ;
  dcterms:format <> .

This is a very simple description of the Semantic Asset Distribution that just gives its description, format, and license. In this example we've used Ed Summers' media types application to provide a URI for the XML MIME type [[EDSU]]

The ADMS Domain Model

UML Diagram of ADMS
UML model of ADMS classes and properties

The classes and properties are described briefly in the following sub-sections

The Primary Concepts

Semantic Asset Repository adms:SemanticAssetRepository

A system or service that provides facilities for storage and maintenance of descriptions of Semantic Assets and Semantic Asset Distributions, and functionality that allows users to search and access these descriptions. A Semantic Asset Repository will typically contain descriptions of several Semantic Assets and related Semantic Asset Distributions.

adms:SemanticAssetRepository is a sub class od dcat:Catalog

Semantic Asset adms:SemanticAsset

An abstract entity that reflects the intellectual content of the asset and represents those characteristics of the asset that are independent of its physical embodiment. This abstract entity combines the FRBR entities work (a distinct intellectual or artistic creation) and expression (the intellectual or artistic realization of a work) [[FRBR]].

Assets can be versioned. Every time the intellectual content of an asset changes, the result is considered to be a new asset that can be linked to previous and next versions of the Asset.

The physical embodiment of an Asset is called a Distribution. A particular Asset may have zero or more Distributions.

adms:SemanticAsset is a sub class of dcat:Dataset

Semantic Asset Distribution adms:SemanticAssetDistribution

A particular physical embodiment of a Semantic Asset, which is an example of the FRBR entity manifestation (the physical embodiment of an expression of a work).

A Distribution is typically a downloadable computer file (but in principle it could also be a paper document or API response) that implements the intellectual content of an Asset.

A particular Distribution is associated with one and only one Asset, while all Distributions of an Asset share the same intellectual content in different physical formats.

Distributions themselves are not versioned. If Distribution 1A is the manifestation of Asset 1 and Distribution 2A is the manifestation of Asset 2, a version relationship will be expressed between Asset 1 and Asset 2, not between Distribution 1A and Distribution 2A. For an illustration of two Assets that each have two Distributions (representations in different formats) see the diagram below.

Diagram showing that Assets are versioned, Distributions are not
The relationship between versioned Semantic Assets and their Distributions

adms:SemanticAssetDistribution is a sub class of dcat:Distribution

Examples of the relationship between Assets and Distributions are:

An Asset without a Distribution
Even before a Semantic Asset is finalized, a description of what it will be can often be made; for example, a description of it can be written, the publisher is already known as is the language. A link to the distribution, the physical document, can only be made when the work is done; until that time, the Asset will have no Distribution associated with it.
An Asset and Distribution embedded in a single file
Some Semantic Assets, such as technical specifications, have some characteristics that are related to the intellectual content such as its description, its language and its version, and some characteristics that are related to the file itself such as its location (if its identifier is not a URL), its format and the usage conditions. In such cases, a single entity is both a Semantic Asset and a Semantic Asset Distribution. Even so, best practice is to assert the Asset → Distribution relationship (i.e. to point to itself) so that queries looking for that relationship will still return a result.
An Asset with multiple Distributions
It is common for a single work to be expressed in multiple formats. For example, RDF documents are often serialized in RDF/XML, Turtle and triples, each of which would be a discrete Distribution.

The Secondary Concepts

In addition to the primary concepts, ADMS includes a number of secondary or supporting concepts:

Asset Type skos:Concept

The classification of an Asset according to a controlled vocabulary, e.g. code list, metadata schema.

Contact Information v:VCard

A contact point for further information about an Asset.

Documentation foaf:Document

Any document that further describes an Asset or gives guidelines for its use.

File Format dcterms:FileFormat

The technical format in which a Distribution is available , e.g. PDF, XSD etc. See also representation technique.

Geographical Coverage dcterms:Location

The country or region to which an Asset or Repository applies.

Identifier adms:Identifier

This is based on the UN/CEFACT Identifier class. [[UNCEFACT]]) which consists of:

  • a content string which is the identifier;
  • an optional identifier for the identifier scheme;
  • an optional identifier for the version of the identifier scheme;
  • an optional identifier for the agency that manages the identifier scheme.

In ADMS this is expressed using the adms:Identifier class with the following properties:

  • the content string should be provided using skos:notation, datatyped with the identifier scheme (inclduing the version number if appropriate);
  • use dcterms:creator to link to a class that represents the agency that manages the identifier scheme and/or adms:schemaAgency to provide the name of the agency as a literal;
  • it may also be useful to provide further properties such as dcterms:issued to provide the date on which the identifier was issued.

An important point to note is that properties of adms:Identifier are properties of the Identifier, not the resource that it identifies or the agency that issued it.

Item adms:Item

An item that is contained inside an Asset, e.g. an individual term in a vocabulary, an individual code in a code list or some other ‘atomic’ element of an Asset.

Interoperability Level skos:Concept

A level as defined in a list such the European Interoperability Framework [[EIF2]] for which an Asset is relevant.

Language dcterms:LinguisticSystem

The language of an Asset if its contains textual information, e.g. the language of the terms in a controlled vocabulary or the language in which a specification is written.

License dcterms:LicenseDocument

The conditions or restrictions that apply to the use of a Distribution, e.g. whether it is in the public domain, or that some restrictions apply such as attribution being required, or that it can only be used for non-commercial purposes etc.

Period of time dcterms:PeriodOfTime

The time period relevant for an Asset, e.g. for its validity

Publisher dcterms:Agent

The organization making a Repository, Asset or Distribution available.

Representation Technique skos:Concept

The machine-readable language in which a Distribution is expressed. This is more fine-grained than file format, for example "Word 2003".

This concept indicates that one of the files in a Semantic Asset Distribution is expressed in the Representation Technique. There may also be other files in the Distribution that are expressed in other Representation Techniques or even files that are not representations at all.

Status skos:Concept

An indication of the maturity of an Asset or Distribution

Theme skos:Concept

The sector that an Asset applies to, e.g. "law" or "environment". Best practice is to user terms from a controlled vocabulary.

Theme Taxonomy skos:ConceptScheme

A controlled vocabulary that contains terms that are used as Themes for the Assets in a Repository.

Properties and Relationships

In the following sub-sections, we set out the properties and relationships (object type properties) used in ADMS. These are listed in alphabetical order, irrespective of namespace.


Any kind of URL that gives access to a Semantic Asset Distribution, e.g. a landing page, download, feed URL, SPARQL endpoint etc. Use dcat:accessURL when you do not have information on which it is or when it is definitely not a download.

Object Type Property:dcat:accessURL
Usage note
  • the value is a URL.
  • If the distribution(s) are accessible only through a landing page (i.e. direct download URLs are not known), then the landing page link should be duplicated as accessURL on a distribution (see also dcat:landingPage).


An alternative name for the Semantic Asset.

Datatype Property:skos:altLabel


A contact point for further information about a Semantic Asset.

Object Type Property:adms:contactPoint


The main documentation or specification of the Semantic Asset

Object Type Property:wdrs:describedby
Usage note>See also dcat:landingPage, adms:relatedDocumentation, adms:relatedWebPage


A description of the Semantic Asset, Semantic Asset Repository or Semantic Distribution.

Datatype Property:dcterms:description


Links a Semantic Asset to an implementation in a particular format.

Object Type Property:adms:distribution
Sub property of:dcat:distribution


This is a direct link from a Semantic Asset Distribution to a downloadable file in a given format, e.g. CSV file or RDF file. The format is described by the distribution's dcterms:format and/or dcat:mediaType.

Object Type Property:dcat:downloadURL


The file format of the distribution.

Object Type Property:dcterms:format
Usage note:dcat:mediaType should be used if the type of the distribution is defined by IANA. Suitable values for dcterms:format include URIs as used in the example. See also adms:representationTechnique.


A Semantic Asset that is contained in the Semantic Asset being described, e.g. when there are several vocabularies defined in a single document.

Object Type Property:adms:includedAsset


An item that is contained in the Semantic Asset (e.g. a concept in a controlled vocabulary, an individual code in a code list or any other ‘atomic’ element).

Object Type Property:adms:includedItem


The interoperability level for which the Semantic Asset is relevant.

Object Type Property:adms:interoperabilityLevel


Used to link a Semantic Asset to a Semantic Asset Repository.

Object Type Property:dcterms:isPartOf


Date of formal issuance (e.g., publication) of the Semantic Asset, Semantic Asset Repository or Semantic Distribution.

Datatype Property:dcterms:issued
Range:rdfs:Literal using the relevant ISO 8601 Date and Time compliant string and typed using the appropriate XML Schema datatype [[XMLSCHEMA-2]]


A word, phrase or tag to describe the Semantic Asset.

Datatype Property:dcat:keyword


A Web page that can be navigated to in a Web browser to gain access to the Semantic Asset, its distributions and/or additional information.

Object Type Property:dcat:landingPage
Usage note:If the Semantic Asset Distribution(s) are accessible only through a landing page (i.e. direct download URLs are not known), then the landing page link should be duplicated as accessURL on a distribution.


The language of the Semantic Asset

Object Type Property:dcterms:LinguisticSystem
Resources defined by the Library of Congress (1, 2) should be used.
If an ISO 639-1 (two-letter) code is defined for language, then its corresponding IRI should be used; if no ISO 639-1 code is defined, then IRI corresponding to the ISO 639-2 (three-letter) code should be used.


A link to the current or latest version of the Semantic Asset.

Object Type Property:xhv:last


Links to the conditions or restrictions for (re-)use of the Semantic Asset Distribution.

Object Type Property:dcterms:license
Usage note:If multiple licenses are given, these licenses apply to all files in the Semantic Asset Distribution.


The media type of the distribution as defined by IANA.

Object Type Property:dcat:mediaType
Usage note:This property should be used when the media type of the distribution is defined in IANA, e.g. text/csv otherwise dcterms:format may be used with different values. See also adms:representationTechnique.


Date of the latest update of the Semantic Asset, Semantic Asset Repository or Semantic Distribution.

Datatype Property:dcterms:modified
Range:rdfs:Literal using the relevant ISO 8601 Date and Time compliant string and typed using the appropriate XML Schema datatype [[XMLSCHEMA-2]]


A link to the next version of the Semantic Asset.

Object Type Property:xhv:next


A link to the previous version of the Semantic Asset.

Object Type Property:xhv:prev


Links a Semantic Asset, Semantic Asset Repository or Seamntic Asset Distribution to the publishing foaf:Agent.

Object Type Property:dcterms:publisher


Links to documentation that contains information related to the Semantic Asset.

Object Type Property:adms:relatedDocumentation


Links to a Web page that contains information related to the Semantic Asset.

Object Type Property:adms:relatedWebPage


A link between two Semantic Assets that are related in some (unspecified) way.

Object Type Property:dcterms:relation


More information about the format in which a Semantic Asset Distribution is released. This is different from the file format as, for example, a ZIP file (file format) could contain an XML schema (representation technique).

Object Type Property:adms:representationTechnique
Usage note:See also dcterms:format and dcat:mediaType.


Links to a sample of a Semantic Asset (which is itself a Semantic Asset).

Object Type Property:adms:sample


The geographic region to which the Semantic Asset or Semantic Asset Repository applies.

Object Type Property:dcterms:spatial


The status of the Semantic Asset in the context of a particular workflow process.

Object Type Property:adms:status


A schema according to which the Semantic Asset Repository can provide data about its content, e.g. ADMS.

Datatype Property:adms:supportedSchema


The time period to which the Semantic Asset applies, e.g. its validity.

Object Type Property:dcterms:temporal


The theme or sector to which the Semantic Asset applies.

Object Type Property:dcat:theme
Sub property of:dcterms:subject


The SKOS Concept Scheme used to classify Semantic Asset Repository's assets.

Object Type Property:dcat:themeTaxonomy


A name given to the Semantic Asset, Semantic Asset Repository or Semantic Distribution.

Datatype Property:dcterms:title


Links Semantic Assets that are translations of each other.

Object Type Property:adms:translation


The type of the Semantic Asset which should be provided using a controlled vocabulary encoded as a SKOS Concept

Object Type Property:dcterms:type
Range:Formally rdfs:Resource but skos:Concept should be used.


A version number or other designation of the Semantic Asset.

Datatype Property:adms:version


A description of changes between this version and the previous version of the Semantic Asset.

Datatype Property:adms:versionNotes