GeoDCAT-AP is an extension of the DCAT application profile for data portals in Europe (DCAT-AP) for describing geospatial datasets, dataset series, and services. Its basic use case is to make spatial datasets, dataset series, and services searchable on general data portals, thereby making geospatial information better findable across borders and sectors. For this purpose, GeoDCAT-AP provides an RDF vocabulary and the corresponding RDF syntax binding for the union of metadata elements of the core profile of ISO 19115:2003 and those defined in the framework of the INSPIRE Directive of the European Union.
This document is the result of the major change release process described in the Change and Release Management Policy for DCAT-AP and was built starting from GeoDCAT-AP version 1.0.1.
The views expressed in this document are purely those of the Author(s) and may not, in any circumstances, be interpreted as stating an official position of the European Commission.
The European Commission does not guarantee the accuracy of the information included in this study, nor does it accept any responsibility for any use thereof.
Reference herein to any specific products, specifications, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favouring by the European Commission.
All care has been taken by the author to ensure that s/he has obtained, where necessary, permission to use any parts of manuscripts including illustrations, maps, and graphs, on which intellectual property rights already exist from the titular holder(s) of such rights or from her/his or their legal representative.
Status of This Document
This section describes the status of this
document at the time of its publication. Other documents may supersede
this document.
GitHub Issues are preferred for
discussion of this specification.
A Recommendation is a specification that, after extensive
consensus-building, has received the endorsement of the Working Group.
The Working Group recommends the wide deployment of this specification.
This document contains version 2.0.0 of the specification for GeoDCAT-AP, an extension of the DCAT application profile for data portals in Europe (DCAT-AP) [DCAT-AP] for describing geospatial datasets, dataset series, and services.
Its basic use case is to make spatial datasets, dataset series, and services searchable on general data portals, thereby making geospatial information better findable across borders and sectors. For this purpose, GeoDCAT-AP provides an RDF vocabulary and the corresponding RDF syntax binding for the union of metadata elements of the core profile of ISO 19115:2003 [ISO-19115] and those defined in the framework of the INSPIRE Directive [INSPIRE-DIR].
The GeoDCAT-AP specification does not replace the INSPIRE Metadata Regulation [INSPIRE-MD-REG] nor the INSPIRE Metadata technical guidelines [INSPIRE-MD] based on ISO 19115 and ISO 19119. Its purpose is to give owners of geospatial metadata the possibility to achieve more by providing the means of an additional implementation through harmonised RDF syntax bindings. Conversion rules to RDF syntax would allow Member States to maintain their collections of INSPIRE-relevant datasets following the INSPIRE Metadata technical guidelines based on [ISO-19115] and [ISO-19119], while at the same time publishing these collections on [DCAT-AP]-conformant data portals. A conversion to an RDF representation allows additional metadata elements to be displayed on general-purposed data portals, provided that such data portals are capable of displaying additional metadata elements. Additionally, data portals may be capable of providing machine-to-machine interfaces where additional metadata could be provided.
1.1 Context
With a view to fostering Europe's digital transformation, the European Commission is investing in frameworks and agreements to provide governments and businesses with the appropriate resources to digitalise their services. There are, for instance, building blocks available for creating a single market for data, where data flows freely within the EU and across sectors for the benefit of businesses, researchers and public administrations.
To this direction, the European Commission launched the European Data Strategy [DataStrategy], as part of the European Commission's priorities for 2019-2024 in order to make the EU a leader in a data-driven society.
Studies previously conducted on behalf of the European Commission (e.g., [Vickery]) shed light on the importance of having data findable and available in machine readable format in order to stimulate its reuse. This vision led to several legislative actions to reduce barriers and promote data sharing, such as the Open Data Directive [OPENDATA-DIR], which turned out to be a driving force towards a more transparent and fair access to government data.
With this regard, the wide range of (open) data portals developed by European public administrations is the result of this mission. These Web-based interfaces allow access to data by providing users means to explore a catalogue of datasets. To facilitate the sharing, discovery and re-use of the data beyond the (open) data portal, common agreements for the exchange of catalogues of datasets are needed. These interoperability agreements enable to connect (open) data catalogues into a pan-european catalogue of datasets.
The DCAT-AP application profile specifies the generic agreements for (open) data portals operated by public administrations in Europe. This specification extends DCAT-AP with additional requirements for geospatial data.
The current document is the result of the major semantic change release process described in the Change and Release Management Policy for DCAT-AP [DCAT-AP-CRMP] and was built starting from GeoDCAT-AP version 1.0.1 [GeoDCAT-AP-20160802], with the purpose of aligning it with DCAT-AP version 2.0.1 [DCAT-AP-20200608] and with version 2.0.1 of the INSPIRE Metadata Technical Guidelines [INSPIRE-MD-20170302].
This work has been carried out in the context of Action 1.1 – Improving semantic interoperability in European eGovernment systems [SEMIC] of the European Commission’s Interoperability solutions for public administrations, businesses and citizens (ISA²) Programme [ISA2], and it is the result of the major semantic change release process described in the Change and Release Management Policy for DCAT-AP [DCAT-AP-CRMP] and was built starting from GeoDCAT-AP version 1.0.1 [GeoDCAT-AP-20160802], with the purpose of aligning it with DCAT-AP version 2.0.1 [DCAT-AP-20200608] and with version 2.0.1 of the INSPIRE Metadata Technical Guidelines [INSPIRE-MD-20170302].
1.2 Scope of the revision
The objective of this work is to produce an updated release of GeoDCAT-AP based on requests for change coming from real-world implementations of the specification and an alignment with [DCAT-AP-20200608] and [INSPIRE-MD-20170302].
As [DCAT-AP-20200608], the Application Profile specified in this document is based on the specification of the Data Catalog Vocabulary (DCAT), originally developed under the responsibility of the Government Linked Data Working Group [GLD] at W3C, and significantly revised in 2020 by the W3C Dataset Exchange Working Group [DXWG]. DCAT is an RDF [RDF11-CONCEPTS] vocabulary designed to facilitate interoperability between data catalogues published on the Web. Additional classes and properties from other well-known vocabularies are re-used where necessary.
The work does not cover implementation issues like mechanisms for exchange of data and expected behaviour of systems implementing the Application Profile other than what is defined in the Conformance Statement in § 6. Conformance.
The Application Profile is intended to facilitate data exchange and therefore the classes and properties defined in this document are only relevant for the data to be exchanged; there are no requirements for communicating systems to implement specific technical environments. The only requirement is that the systems can export and import data in RDF in conformance with this Application Profile.
1.3 A DCAT-AP extension
The GeoDCAT-AP specification is designed as an extension of DCAT-AP in conformance with the guidelines for the creation of DCAT-AP extensions [DCAT-AP-EG]. The DCAT-AP Application Profile on which this document is based is the DCAT-AP specification of 8 June 2020 [DCAT-AP-20200608]. According to the same principles DCAT-AP is in itself an extension of DCAT.
This dependency must be taken into account while reading and using this specification. When implementing GeoDCAT-AP, these specifications should be consulted first, to fill in any missing gaps in this document.
2. Terminology used in the Application Profile
A Vocabulary is a specification that determines the semantics of terms (classes and properties) in a broad context of information exchange. The defined terms are higly reusable.
A Controlled Vocabulary is an organised arrangement of words and phrases used to index content and/or to retrieve content through browsing or searching. It typically includes preferred and variant terms and has a defined scope or describes a specific domain [GETTY]. Within this specification, it is also used as a synonym for a codelist.
An Application Profile is a specification that re-uses terms from one or more base standards (vocabularies), 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.
In the following sections, classes and properties are grouped under headings ‘mandatory’, ‘recommended’ and ‘optional’. These terms have the following meaning:
Mandatory class: a receiver MUST be able to process information about instances of the class; a sender MUST provide information about instances of the class.
Recommended class: a receiver MUST be able to process information about instances of the class; a sender SHOULD provide information about instances of the class; a sender of data MUST provide information about instances of the class, if such information is available.
Optional class: a receiver MUST be able to process information about instances of the class; a sender MAY provide the information but is not obliged to do so.
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 information for that property; a sender MUST provide information for that property, if such information 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 class: a receiver SHOULD be able to process information about instances of that class; a sender SHOULD NOT provide information about instances of that class.
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 propertry.
The meaning of the terms MUST, MUST NOT, SHOULD and MAY in this section and in the following sections are as defined in [RFC2119].
In the given context, the term "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.).
The class ‘Distribution’ is classified as ‘Recommended’ in § 3.2 Recommended Classes to allow for cases that a particular Dataset does not have a downloadable Distribution, and in such cases the sender of data would not be able to provide this information. However, it can be expected that in the majority of cases Datasets do have downloadable Distributions, and in such cases the provision of information on the Distribution is mandatory.
All other classes are classified as ‘Optional’ in § 3.3 Optional Classes. A further description of the optional classes is only included as a sub-section in § 4. Application Profile Properties per Class if the Application Profile specifies mandatory or recommended properties for them.
Classes no longer included in this version of the specification, or replaced with other ones, are classified as ‘Deprecated’ in § 3.4 Deprecated Classes.
Finally, classes and properties added in this Application Profile and extending [DCAT-AP] are marked with a prepended “plus” sign (+), and summarised in the reference table in § A.1 Classes and properties added by GeoDCAT-AP.
2.1 Namespaces
The namespace for GeoDCAT-AP is: http://data.europa.eu/930/
The suggested namespace prefix is: geodcat
The Application Profile reuses terms from various existing specifications, following established best practices [DWBP]. The following table indicates the full list of corresponding namespaces used in this document.
These extensions are meant to provide a DCAT-AP-conformant representation of geospatial metadata, identified by defining RDF syntax mappings covering the union of the elements in the INSPIRE metadata schema [INSPIRE-MD-REG] [INSPIRE-MD] and the core profile of [ISO-19115], following the criteria illustrated in § B. INSPIRE and ISO 19115 Mappings.
The current specification does not change the set of geospatial metadata elements already covered in its previous version [GeoDCAT-AP-20160802], but rather it updates some of the corresponding mappings based on the new classes and properties included in [DCAT-AP-20200608], following the release of version 2 of the W3C Data Catalog (DCAT) Vocabulary [VOCAB-DCAT-2], and aligns them with version 2.0.1 of the INSPIRE Metadata Technical Guidelines [INSPIRE-MD-20170302]. With the same objective, new terms have been defined in the GeoDCAT-AP namespace for the specification of agent roles (see § 7. Agent Roles) and spatial resolution (see § 4.20.1 Instances of Metric). As a result, some of the classes and properties defined in [GeoDCAT-AP-20160802] have been deprecated and replaced by the equivalent ones in [DCAT-AP-20200608] and by the newly defined terms.
An entity (e.g., an individual or an organisation) that is associated with Catalogues, Catalogue Records, Data Services, or Datasets. If the Agent is an organisation, the use of the Organization Ontology [VOCAB-ORG] is recommended. See § 7. Agent Roles for a discussion on Agent roles.
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 [BCP47].
An activity carried out by an Agent over an entity, according to a plan, and generating another entity.
In GeoDCAT-AP, this class SHOULD be used to specify a testing activity over a resource, against a given Standard, producing as output a conformance degree.
A value that allows the contents of a file to be authenticated. This class allows the results of a variety of checksum and cryptographic message digest algorithms to be represented.
An identifier in a particular context, consisting of the string that 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
A description following the [VCARD-RDF] specification, e.g. to provide telephone number and e-mail address for a contact point. Note that the class vcard:Kind is the parent class for the four explicit types of vCards (vcard:Individual, vcard:Organization, vcard:Location, vcard:Group).
A statement of any changes in ownership and custody of a resource since its creation that are significant for its authenticity, integrity, and interpretation
A statement about the intellectual property rights (IPR) held in or over a resource, a legal document giving official permission to do something with a resource, or a statement about access rights.
A system that provides one or more functions [DCTERMS].
In the geospatial domain, a service is defined as the set of operations which may be performed, by invoking a computer application, on the spatial data contained in spatial data sets or on the related metadata [INSPIRE-GLOSSARY].
A quick reference table of properties per class is included in § A. Quick Reference of Classes and Properties. The list of included properties contains all the properties in [DCAT-AP-20200608], plus a selection of properties from [VOCAB-DCAT-2] and [DCTERMS], on which GeoDCAT-AP expresses additional constraints or on which GeoDCAT-AP wants to emphasise their usage.
Examples on the use of these properties, encoded in [Turtle], are included in the relevant sections. The examples are also available in [Turtle], RDF/XML [RDF-SYNTAX-GRAMMAR], and JSON-LD [JSON-LD11] from a separate folder.
4.1 +Activity
Note
Class name
Activity
Obligation
Optional
URI
prov:Activity
Usage note
An activity carried out by an Agent over an entity, according to a plan, and generating another entity.
In GeoDCAT-AP, this class SHOULD be used to specify a testing activity over a resource, against a given Standard, producing as output a conformance degree.
This property refers to the Entity generated by the Activity.
1..n
+qualified association
prov:qualifiedAssociation
prov:Association
This property refers to the Plan according to which the Activity has been carried out, and possibly to the Agent who played a role in it.
1..n
+used
prov:used
prov:Entity
This property refers to the entity (e.g., a Catalogue, a Dataset, a Data Service) which was the subject of the Activity.
This property MAY be omitted in case its inverse property prov:wasUsedBy is specified.
1..n
4.1.2 Examples for Activity
Example 1 shows the use of class prov:Activity to specify the results of a testing activity assessing the conformance of a given resource against a given specification - as illustrated in § 8. Conformance Test Results.
The administrative area of an Address of the Kind. Depending on the country, this corresponds to a province, a county, a region, or a state.
0..1
+city
vcard:locality
rdfs:Literal
The city of an Address of the Kind.
0..1
+country
vcard:country-name
rdfs:Literal
The country of an Address of the Kind.
0..1
+postal code
vcard:postal-code
rdfs:Literal
The postal code of an Address of the Kind.
0..1
+street address
vcard:street-address
rdfs:Literal
The street name and civic number of an Address of the Kind.
0..1
4.3.2 Examples for Address (Kind)
4.4 Agent
Class name
Agent
Obligation
Mandatory
URI
foaf:Agent
Usage note
An entity (e.g., an individual or an organisation) that is associated with Catalogues, Catalogue Records, Data Services, or Datasets. If the Agent is an organisation, the use of the Organization Ontology [VOCAB-ORG] is recommended. See § 7. Agent Roles for a discussion on Agent roles.
This property contains a name of the Agent. This property can be repeated for different versions of the name (e.g. the name in different languages) - see § 9. Accessibility and Multilingual Aspects.
1..n
4.4.2 Recommended property for Agent
Property
URI
Range
Usage note
Card.
type
dct:type
skos:Concept
This property refers to a type of the Agent that makes the Catalogue, Catalogue Record, Data Service, or Dataset available
0..1
4.4.3 Optional properties for Agent
Note
Property
URI
Range
Usage note
Card.
+address
locn:address
locn:Address
This property MAY be used to specify the postal address of the Agent.
0..1
+affiliation
org:memberOf
org:Organization
This property MAY be used to specify the affiliation of the Agent.
0..1
+email
foaf:mbox
owl:Thing
This property MAY be used to provide the email address of the Agent, specified using fully qualified mailto: URI scheme [RFC6068].
0..1
+phone
foaf:phone
owl:Thing
This property MAY be used to provide the phone number of the Agent, specified using fully qualified tel: URI scheme [RFC3966].
0..1
+URL
foaf:workplaceHomepage
foaf:Document
This property MAY be used to specify the Web site of the Agent.
The use of this class in GeoDCAT-AP is illustrated in § 7. Agent Roles.
4.5.1 Mandatory properties for Attribution
Note
Property
URI
Range
Usage note
Card.
+agent
prov:agent
prov:Agent
This property refers to the Agent to whom the resource is attributed.
1..n
+had role
dcat:hadRole
dcat:Role
This property refers to the function of an Agent with respect to another entity or resource.
In GeoDCAT-AP, this property SHOULD take as value one of the URIs of the "Responsible party roles" code list operated by the INSPIRE Registry [INSPIRE-RPR].
This property links the Catalogue with a Dataset that is part of the Catalogue.
1..n
description
dct:description
rdfs:Literal
This property contains a free-text account of the Catalogue. This property can be repeated for parallel language versions of the description - see § 9. Accessibility and Multilingual Aspects.
1..n
publisher
dct:publisher
foaf:Agent
This property refers to an entity (organisation) responsible for making the Catalogue available.
1..1
title
dct:title
rdfs:Literal
This property contains a name given to the Catalogue. This property can be repeated for parallel language versions of the name - see § 9. Accessibility and Multilingual Aspects.
1..n
4.6.2 Recommended properties for Catalogue
Property
URI
Range
Usage note
Card.
homepage
foaf:homepage
foaf:Document
This property refers to a Web page that acts as the main page for the Catalogue.
0..1
language
dct:language
dct:LinguisticSystem
This property refers to a language used in the textual metadata describing titles, descriptions, etc. of the resources documented in the Catalogue (Data Services, Data Sets, and other Catalogues). This property can be repeated if the metadata is provided in multiple languages - see § 9. Accessibility and Multilingual Aspects.
0..n
licence
dct:license
dct:LicenseDocument
This property refers to the licence under which the Catalogue can be used or reused.
0..1
release date
dct:issued
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the date of formal issuance (e.g., publication) of the Catalogue.
0..1
spatial / geographic
dct:spatial
dct:Location
This property refers to a geographic area covered by the Catalogue.
0..n
themes
dcat:themeTaxonomy
skos:ConceptScheme
This property refers to a knowledge organization system used to classify the resourcees documented in the Catalogue (Data Services, Datasets, and other Catalogues).
0..n
update / modification date
dct:modified
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the most recent date on which the Catalogue was modified.
0..1
4.6.3 Optional properties for Catalogue
Note
Property
URI
Range
Usage note
Card.
+access rights
dct:accessRights
dct:RightsStatement
This property MAY include information regarding access or restrictions based on privacy, security, or other policies.
For INSPIRE metadata, this property SHOULD be used with the URIs of the "Limitations on public access" code list operated by the INSPIRE Registry [INSPIRE-LPA].
0..1
catalogue
dcat:catalog
dcat:Catalog
This property refers to a Catalogue whose contents are of interest in the context of this Catalogue.
0..n
+conforms to
dct:conformsTo
dct:Standard
This property refers to an implementing rule or other specification.
0..n
+contact point
dcat:contactPoint
vcard:Kind
This property contains contact information that can be used for sending comments about the Catalogue.
0..n
+creation date
dct:created
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the date on which the Catalogue has been first created.
0..1
creator
dct:creator
foaf:Agent
This property refers to the Agent primarily responsible for producing the Catalogue.
0..1
has part
dct:hasPart
dcat:Catalog
This property refers to a related Catalogue that is part of the described Catalogue.
0..n
+identifier
dct:identifier
rdfs:Literal
This property contains the main identifier for the Catalogue, e.g. the URI or other unique identifier.
0..n
is part of
dct:isPartOf
dcat:Catalog
This property refers to a related Catalogue in which the described Catalogue is physically or logically included.
0..1
+keyword / tag
dcat:keyword
rdfs:Literal
This property contains a keyword or tag describing the Catalogue.
0..n
+qualified attribution
prov:qualifiedAttribution
prov:Attribution
This property refers to a link to an Agent having some form of responsibility for the Catalogue.
0..n
record
dcat:record
dcat:CatalogRecord
This property refers to a Catalogue Record that is part of the Catalogue.
0..n
+reference system
dct:conformsTo
dct:Standard
This property SHOULD be used to specify the reference system used in the Catalogue.
Spatial reference systems SHOULD be specified by using the corresponding URIs from the “EPSG coordinate reference systems” register operated by OGC [OGC-EPSG].
0..n
rights
dct:rights
dct:RightsStatement
This property refers to a statement that specifies rights associated with the Catalogue.
0..1
+rights holder
dct:rightsHolder
foaf:Agent
This property refers to an Agent (organisation) holding rights on the Catalogue.
0..n
service
dcat:service
dcat:DataService
This property refers to a Data Service that is listed in the Catalogue.
0..n
+temporal coverage
dct:temporal
dct:PeriodOfTime
This property refers to a temporal period that the Catalogue covers.
0..n
+theme / category
dcat:theme
skos:Concept
This property refers to a Category of the Catalogue. A Catalogue may be associated with multiple Categories.
0..n
+topic category
dct:subject
skos:Concept
In GeoDCAT-AP, this property SHOULD take as value one of the URIs of the "Topic categories in accordance with EN ISO 19115" code list operated by the INSPIRE Registry [INSPIRE-TC].
0..n
+was used by
prov:wasUsedBy
prov:Activity
This property refers to an Activity that used the Catalogue.
In GeoDCAT-AP, this property MAY be used to specify a testing Activity over a Catalogue, against a given Standard, producing as output a conformance degree.
0..n
+custodian
geodcat:custodian
foaf:Agent
Party that accepts accountability and responsibility for the data and ensures appropriate care and maintenance of the resource [ISO-19115].
This property links the Catalogue Record to the Dataset, Data service or Catalogue described in the record.
1..1
update / modification date
dct:modified
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the most recent date on which the Catalogue Record was changed or modified.
1..1
4.7.2 Recommended properties for Catalogue Record
Property
URI
Range
Usage note
Card.
application profile
dct:conformsTo
dct:Standard
This property refers to an Application Profile that the Catalogue Record conforms to
0..1
change type
adms:status
skos:Concept
This property refers to the type of the latest revision of a Catalogue Record.
0..1
listing date
dct:issued
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the date on which the Catalogue Record was included in the Catalogue.
0..1
4.7.3 Optional properties for Catalogue Record
Note
Property
URI
Range
Usage note
Card.
+character encoding
cnt:characterEncoding
rdfs:Literal
This property SHOULD be used to specify the character encoding of the Catalogue Record, by using as value the character set names in the IANA register [IANA-CHARSETS].
0..n
+contact point
dcat:contactPoint
vcard:Kind
This property contains contact information that can be used for sending comments about the Catalogue Record.
0..n
+creation date
dct:created
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the date on which the Catalogue Record has been first created.
0..1
+creator
dct:creator
foaf:Agent
This property refers to the Agent primarily responsible for producing the Catalogue Record.
0..n
description
dct:description
rdfs:Literal
This property contains a free-text account of the Catalogue Record. This property can be repeated for parallel language versions of the description - see § 9. Accessibility and Multilingual Aspects.
0..n
+identifier
dct:identifier
rdfs:Literal
This property contains the main identifier for the Catalogue Record, e.g., the URI or other unique identifier in the context of the Catalogue.
0..n
language
dct:language
dct:LinguisticSystem
This property refers to a language used in the textual metadata describing titles, descriptions, etc. of the Catalogue Record. This property can be repeated if the metadata is provided in multiple languages - see § 9. Accessibility and Multilingual Aspects.
0..n
+publisher
dct:publisher
foaf:Agent
This property refers to an Agent (organisation) responsible for making the Catalogue Record available.
0..1
+qualified attribution
prov:qualifiedAttribution
prov:Attribution
This property refers to a link to an Agent having some form of responsibility for the Catalogue Record.
0..n
+rights holder
dct:rightsHolder
foaf:Agent
This property refers to an Agent (organisation) holding rights on the Catalogue Record.
0..n
source metadata
dct:source
dcat:CatalogRecord
This property refers to the original metadata record that was used in creating the Catalogue Record.
In GeoDCAT-AP, this MAY refer to an INSPIRE / [ISO-19115] record that was transformed into the current Geo/DCAT-AP one.
0..1
title
dct:title
rdfs:Literal
This property contains a name given to the Catalogue Record. This property can be repeated for parallel language versions of the name - see § 9. Accessibility and Multilingual Aspects.
0..n
+custodian
geodcat:custodian
foaf:Agent
Party that accepts accountability and responsibility for the data and ensures appropriate care and maintenance of the resource [ISO-19115].
This property contains a preferred label of the Category. This property can be repeated for parallel language versions of the label - see § 9. Accessibility and Multilingual Aspects.
1..n
4.8.2 Optional property for Category
Note
Property
URI
Range
Usage note
Card.
+category scheme
skos:inScheme
skos:ConceptScheme
This property MAY be used to specify the Category Scheme to which the Category belongs.
0..1
4.8.3 Examples for Category
4.9 Category Scheme
Class name
Category scheme
Obligation
Recommended
URI
skos:ConceptScheme
Usage note
A concept collection (e.g. controlled vocabulary) in which the Category is defined.
This property contains the date on which the Category Scheme has been first created.
0..1
+release date
dct:issued
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the date of formal issuance (e.g., publication) of the Category Scheme.
0..1
+update / modification date
dct:modified
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the most recent date on which the Category Scheme was changed or modified.
0..1
+version
owl:versionInfo
rdfs:Literal
This property contains a version number or other version designation of the Category Scheme.
0..1
4.9.3 Examples for Category Scheme
4.10 Checksum
Class name
Checksum
Obligation
Optional
URI
spdx:Checksum
Usage note
A value that allows the contents of a file to be authenticated. This class allows the results of a variety of checksum and cryptographic message digest algorithms to be represented.
This property identifies the algorithm used to produce the subject Checksum. Currently, SHA-1 is the only supported algorithm. It is anticipated that other algorithms will be supported at a later time.
1..1
checksum value
spdx:checksumValue
rdfs:Literal typed as xsd:hexBinary
This property provides a lower case hexadecimal encoded digest value produced using a specific algorithm.
1..1
4.11 Data Service
Class name
Data Service
Obligation
Optional
URI
dcat:DataService
Usage note
A collection of operations that provides access to one or more datasets or data processing functions.
The root location or primary endpoint of the Service (an IRI).
1..n
title
dct:title
rdfs:Literal
This property contains a name given to the Data Service. This property can be repeated for parallel language versions of the name - see § 9. Accessibility and Multilingual Aspects.
1..n
4.11.2 Recommended properties for Data Service
Property
URI
Range
Usage note
Card.
endpoint description
dcat:endpointDescription
rdfs:Resource
This property contains a description of the Data Services available via the endpoints, including their operations, parameters etc. The property gives specific details of the actual endpoint instances, while dct:conformsTo is used to indicate the general standard or specification that the endpoints implement.
0..n
serves dataset
dcat:servesDataset
dcat:Dataset
This property refers to a Dataset that this Data Service can distribute.
0..n
4.11.3 Optional properties for Data Service
Note
Property
URI
Range
Usage note
Card.
access rights
dct:accessRights
dct:RightsStatement
This property MAY include information regarding access or restrictions based on privacy, security, or other policies.
For INSPIRE metadata, this property SHOULD be used with the URIs of the "Limitations on public access" code list operated by the INSPIRE Registry [INSPIRE-LPA].
0..1
+conforms to
dct:conformsTo
dct:Standard
This property is used to indicate the general standard or specification that the Data Service endpoints implement.
0..n
+contact point
dcat:contactPoint
vcard:Kind
This property contains contact information that can be used for sending comments about the Data Service.
0..n
+creation date
dct:created
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the date on which the Data Service has been first created.
0..1
+creator
dct:creator
foaf:Agent
This property refers to the Agent primarily responsible for producing the Data Service..
0..n
description
dct:description
rdfs:Literal
This property contains a free-text account of the Data Service. This property can be repeated for parallel language versions of the description - see § 9. Accessibility and Multilingual Aspects.
0..n
+identifier
dct:identifier
rdfs:Literal
This property contains the main identifier for the Data Service, e.g. the URI or other unique identifier in the context of the Catalogue.
0..n
+keyword / tag
dcat:keyword
rdfs:Literal
This property contains a keyword or tag describing the Data Service.
0..n
+language
dct:language
dct:LinguisticSystem
This property refers to a language supported by the Data Service. This property can be repeated if multiple languages are supported in the Data Service - see § 9. Accessibility and Multilingual Aspects.
0..n
licence
dct:license
dct:LicenseDocument
This property contains the licence under which the Data Service is made available.
0..1
+publisher
dct:publisher
foaf:Agent
This property refers to an Agent (organisation) responsible for making the Data Service available.
0..1
+qualified attribution
prov:qualifiedAttribution
prov:Attribution
This property refers to a link to an Agent having some form of responsibility for the Data Service.
0..n
+reference system
dct:conformsTo
dct:Standard
This property SHOULD be used to specify the reference system used in the Data Service.
Spatial reference systems SHOULD be specified by using the corresponding URIs from the “EPSG coordinate reference systems” register operated by OGC [OGC-EPSG].
0..n
+release date
dct:issued
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the date of formal issuance (e.g., publication) of the Data Service.
0..1
+rights holder
dct:rightsHolder
foaf:Agent
This property refers to an Agent (organisation) holding rights on the Data Service..
0..n
+service category
dct:type
skos:Concept
In GeoDCAT-AP, this property SHOULD take as value one of the URIs of the "Classification of spatial data services" code list operated by the INSPIRE Registry [INSPIRE-SDSC].
0..1
+service type
dct:type
skos:Concept
In GeoDCAT-AP, this property SHOULD take as value one of the URIs of the "Spatial data service types" code list operated by the INSPIRE Registry [INSPIRE-SDST].
0..1
+spatial / geographic coverage
dct:spatial
dct:Location
This property refers to a geographic region that is covered by the Data Service.
This property refers to the minimum spatial separation resolvable in a Data Service, measured in metres.
0..n
+spatial resolution as text
rdfs:comment
rdfs:Literal
This property MAY be used to express spatial resolution as free-text, when it cannot be specified via dqv:hasQualityMeasurement and dcat:spatialResolutionInMeters.
0..n
+temporal coverage
dct:temporal
dct:PeriodOfTime
This property refers to a temporal period that the Data Service covers.
0..n
+temporal resolution
dcat:temporalResolution
rdfs:Literal typed as xsd:duration
This property refers to the minimum time period resolvable in the Data Service.
0..n
+theme / category
dcat:theme
skos:Concept
This property refers to a Category of the Data Service. A Data Service may be associated with multiple Categories.
0..n
+topic category
dct:subject
skos:Concept
In GeoDCAT-AP, this property SHOULD take as value one of the URIs of the "Topic categories in accordance with EN ISO 19115" code list operated by the INSPIRE Registry [INSPIRE-TC].
0..n
+type
dct:type
skos:Concept
In GeoDCAT-AP, this property SHOULD take as value one of the URIs of the "Resource types" code list operated by the INSPIRE Registry [INSPIRE-RT] - namely the one corresponding to "Spatial data service".
0..1
+update / modification date
dct:modified
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the most recent date on which the Data Service was changed or modified.
0..1
+was used by
prov:wasUsedBy
prov:Activity
This property refers to an Activity that used the Data Service.
In GeoDCAT-AP, this property MAY be used to specify a testing Activity over a Data Service, against a given Standard, producing as output a conformance degree.
0..n
+custodian
geodcat:custodian
foaf:Agent
Party that accepts accountability and responsibility for the data and ensures appropriate care and maintenance of the resource [ISO-19115].
This property contains a free-text account of the Dataset. This property can be repeated for parallel language versions of the description - see § 9. Accessibility and Multilingual Aspects.
1..n
title
dct:title
rdfs:Literal
This property contains a name given to the Dataset. This property can be repeated for parallel language versions of the name - see § 9. Accessibility and Multilingual Aspects.
1..n
4.12.2 Recommended properties for Dataset
Property
URI
Range
Usage note
Card.
contact point
dcat:contactPoint
vcard:Kind
This property contains contact information that can be used for sending comments about the Dataset.
0..n
dataset distribution
dcat:distribution
dcat:Distribution
This property links the Dataset to an available Distribution.
0..n
keyword / tag
dcat:keyword
rdfs:Literal
This property contains a keyword or tag describing the Dataset.
0..n
publisher
dct:publisher
foaf:Agent
This property refers to an Agent (organisation) responsible for making the Dataset available.
0..1
spatial / geographic coverage
dct:spatial
dct:Location
This property refers to a geographic region that is covered by the Dataset.
0..n
temporal coverage
dct:temporal
dct:PeriodOfTime
This property refers to a temporal period that the Dataset covers.
0..n
theme / category
dcat:theme
skos:Concept
This property refers to a category of the Dataset. A Dataset may be associated with multiple themes.
0..n
4.12.3 Optional properties for Dataset
Note
Property
URI
Range
Usage note
Card.
access rights
dct:accessRights
dct:RightsStatement
This property refers to information that indicates whether the Dataset is open data, has access restrictions or is not public.
For INSPIRE metadata, this property SHOULD be used with the URIs of the "Limitations on public access" code list operated by the INSPIRE Registry [INSPIRE-LPA].
0..1
conforms to
dct:conformsTo
dct:Standard
This property refers to an implementing rule or other specification.
0..n
+creation date
dct:created
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the date on which the Dataset has been first created.
0..1
creator
dct:creator
foaf:Agent
This property refers to the Agent primarily responsible for producing the Dataset.
0..1
documentation
foaf:page
foaf:Document
This property refers to a page or document about this Dataset.
0..n
frequency
dct:accrualPeriodicity
dct:Frequency
This property refers to the frequency at which the Dataset is updated.
0..1
has version
dct:hasVersion
dcat:Dataset
This property refers to a related Dataset that is a version, edition, or adaptation of the described Dataset.
0..n
identifier
dct:identifier
rdfs:Literal
This property contains the main identifier for the Dataset, e.g., the URI or other unique identifier in the context of the Catalogue.
0..n
is referenced by
dct:isReferencedBy
rdfs:Resource
This property is about a related resource, such as a publication, that references, cites, or otherwise points to the Dataset.
0..n
is version of
dct:isVersionOf
dcat:Dataset
This property refers to a related Dataset of which the described Dataset is a version, edition, or adaptation.
0..n
landing page
dcat:landingPage
foaf:Document
This property refers to a Web page that provides access to the Dataset, its Distributions and/or additional information. It is intended to point to a landing page at the original data provider, not to a page on a site of a third party, such as an aggregator.
0..n
language
dct:language
dct:LinguisticSystem
This property refers to a language of the Dataset. This property can be repeated if there are multiple languages in the Dataset - see § 9. Accessibility and Multilingual Aspects.
0..n
other identifier
adms:identifier
adms:Identifier
This property refers to a secondary identifier of the Dataset, such as MAST/ADS [MAST-ADS], [DataCite], [DOI], [EZID] or [W3ID].
0..n
provenance
dct:provenance
dct:ProvenanceStatement
This property contains a statement about the lineage of a Dataset.
0..n
qualified attribution
prov:qualifiedAttribution
prov:Attribution
This property refers to a link to an Agent having some form of responsibility for the Dataset.
0..n
qualified relation
dcat:qualifiedRelation
dcat:Relationship
This property provides a link to a description of a relationship with another resource.
0..n
+reference system
dct:conformsTo
dct:Standard
This property SHOULD be used to specify the reference system used in the Dataset.
Spatial reference systems SHOULD be specified by using the corresponding URIs from the “EPSG coordinate reference systems” register operated by OGC [OGC-EPSG].
0..n
related resource
dct:relation
rdfs:Resource
This property refers to a related resource.
0..n
release date
dct:issued
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the date of formal issuance (e.g., publication) of the Dataset.
0..1
+rights holder
dct:rightsHolder
foaf:Agent
This property refers to an Agent (organisation) holding rights on the Dataset.
0..n
sample
adms:sample
dcat:Distribution
This property refers to a sample Distribution of the Dataset.
0..n
source
dct:source
dcat:Dataset
This property refers to a related Dataset from which the described Dataset is derived.
This property refers to the minimum spatial separation resolvable in a Dataset, measured in metres.
0..n
+spatial resolution as text
rdfs:comment
rdfs:Literal
This property MAY be used to express spatial resolution as free-text, when it cannot be specified via dqv:hasQualityMeasurement and dcat:spatialResolutionInMeters.
0..n
temporal resolution
dcat:temporalResolution
rdfs:Literal typed as xsd:duration
This property refers to the minimum time period resolvable in the Dataset.
0..n
+topic category
dct:subject
skos:Concept
In GeoDCAT-AP, this property SHOULD take as value one of the URIs of the "Topic categories in accordance with EN ISO 19115" code list operated by the INSPIRE Registry [INSPIRE-TC].
0..n
type
dct:type
skos:Concept
This property refers to the type of the Dataset. A controlled vocabulary for the values has not been established in [DCAT-AP].
In GeoDCAT-AP, this property SHOULD take as value one of the URIs of the "Resource types" code list operated by the INSPIRE Registry [INSPIRE-RT]. For Datasets, the possible values are those corresponding to "Spatial data set" and "Spatial data set series".
0..1
update / modification date
dct:modified
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the most recent date on which the Dataset was changed or modified.
0..1
version
owl:versionInfo
rdfs:Literal
This property contains a version number or other version designation of the Dataset.
0..1
version notes
adms:versionNotes
rdfs:Literal
This property contains a description of the differences between this version and a previous version of the Dataset. This property can be repeated for parallel language versions of the version notes - see § 9. Accessibility and Multilingual Aspects.
0..n
was generated by
prov:wasGeneratedBy
prov:Activity
This property refers to an Activity that generated, or provides the business context for, the creation of the Dataset.
0..n
+was used by
prov:wasUsedBy
prov:Activity
This property refers to an Activity that used the Dataset.
In GeoDCAT-AP, this property MAY be used to specify a testing Activity over a Dataset, against a given Standard, producing as output a conformance degree.
0..n
+custodian
geodcat:custodian
foaf:Agent
Party that accepts accountability and responsibility for the data and ensures appropriate care and maintenance of the resource [ISO-19115].
This property contains a URL that gives access to a Distribution of the Dataset. The resource at the access URL may contain information about how to get the Distribution.
1..n
4.13.2 Recommended properties for Distribution
Property
URI
Range
Usage note
Card.
availability
dcatap:availability
skos:Concept
This property indicates how long it is planned to keep the Distribution of the Dataset available.
0..1
description
dct:description
rdfs:Literal
This property contains a free-text account of the Distribution. This property can be repeated for parallel language versions of the description - see § 9. Accessibility and Multilingual Aspects.
0..n
format
dct:format
dct:MediaTypeOrExtent
This property refers to the file format of the Distribution.
0..1
licence
dct:license
dct:LicenseDocument
This property refers to the licence under which the Distribution is made available.
0..1
4.13.3 Optional properties for Distribution
Note
Property
URI
Range
Usage note
Card.
+access rights
dct:accessRights
dct:RightsStatement
This property MAY include information regarding access or restrictions based on privacy, security, or other policies.
For INSPIRE metadata, this property SHOULD be used with the URIs of the "Limitations on public access" code list operated by the INSPIRE Registry [INSPIRE-LPA].
0..1
access service
dcat:accessService
dcat:DataService
This property refers to a Data Service that gives access to the Distribution of the Dataset.
0..n
byte size
dcat:byteSize
rdfs:Literal typed as xsd:decimal
This property contains the size of a Distribution in bytes.
0..1
+character encoding
cnt:characterEncoding
rdfs:Literal
This property SHOULD be used to specify the character encoding of the Distribution, by using as value the character set names in the IANA register [IANA-CHARSETS].
0..n
checksum
spdx:checksum
spdx:Checksum
This property provides a mechanism that can be used to verify that the contents of a Distribution have not changed. The checksum is related to the download URL.
0..1
compression format
dcat:compressFormat
dct:MediaType
This property refers to the format of the file in which the data is contained in a compressed form, e.g., to reduce the size of the downloadable file. It SHOULD be expressed using a media type as defined in the official register of media types managed by IANA [IANA-MEDIA-TYPES].
0..1
documentation
foaf:page
foaf:Document
This property refers to a page or document about this Distribution.
0..n
download URL
dcat:downloadURL
rdfs:Resource
This property contains a URL that is a direct link to a downloadable file in a given format.
0..n
has policy
odrl:hasPolicy
odrl:Policy
This property refers to the policy expressing the rights associated with the Distribution if using the [VOCAB-ODRL] vocabulary.
0..1
language
dct:language
dct:LinguisticSystem
This property refers to a language used in the Distribution. This property can be repeated if the metadata is provided in multiple languages - see § 9. Accessibility and Multilingual Aspects.
0..n
linked schemas
dct:conformsTo
dct:Standard
This property refers to an established schema to which the described Distribution conforms.
0..n
media type
dcat:mediaType
dct:MediaType
This property refers to the media type of the Distribution as defined in the official register of media types managed by IANA [IANA-MEDIA-TYPES].
0..1
packaging format
dcat:packageFormat
dct:MediaType
This property refers to the format of the file in which one or more data files are grouped together, e.g. to enable a set of related files to be downloaded together. It SHOULD be expressed using a media type as defined in the official register of media types managed by IANA [IANA-MEDIA-TYPES].
0..1
+reference system
dct:conformsTo
dct:Standard
This property SHOULD be used to specify the reference system used in the Distribution.
Spatial reference systems SHOULD be specified by using the corresponding URIs from the “EPSG coordinate reference systems” register operated by OGC [OGC-EPSG].
0..n
release date
dct:issued
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the date of formal issuance (e.g., publication) of the Distribution.
0..1
+representation technique
adms:representationTechnique
skos:Concept
This property MAY be used to provide more information about the format in which an 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).
In GeoDCAT-AP, this property SHOULD be used to express the spatial representation type (grid, vector, tin), by using the URIs of the corresponding code list operated by the INSPIRE Registry [INSPIRE-SRT].
0..1
rights
dct:rights
dct:RightsStatement
This property refers to a statement that specifies rights associated with the Distribution.
This property refers to the minimum spatial separation resolvable in a Distribution, measured in metres.
0..n
+spatial resolution as text
rdfs:comment
rdfs:Literal
This property MAY be used to express spatial resolution types that cannot be specified via dcat:spatialResolutionInMeters - i.e., spatial resolution as equivalent scale, angular distance, vertical distance.
0..n
status
adms:status
skos:Concept
This property refers to the maturity of the Distribution. It MUST take one of the values Completed, Deprecated, Under Development, Withdrawn from the ADMS status [ADMS-SKOS] vocabulary.
0..1
temporal resolution
dcat:temporalResolution
rdfs:Literal typed as xsd:duration
This property refers to the minimum time period resolvable in the Distribution.
0..n
title
dct:title
rdfs:Literal
This property contains a name given to the Distribution. This property can be repeated for parallel language versions of the description - see § 9. Accessibility and Multilingual Aspects.
0..n
update / modification date
dct:modified
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the most recent date on which the Distribution was changed or modified.
This property contains a free-text account of the Document. This property can be repeated for parallel language versions of the description - see § 9. Accessibility and Multilingual Aspects.
0..n
+title
dct:title
rdfs:Literal
This property contains a name given to the Document. This property can be repeated for parallel language versions of the name - see § 9. Accessibility and Multilingual Aspects.
0..n
4.14.2 Examples for Document
4.15 Identifier
Class name
Identifier
Obligation
Optional
URI
adms:Identifier
Usage note
An identifier in a particular context, consisting of the string that 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
rdfs:Literal typed with the URI of one of the members of the DataCite Resource Identifier Scheme [DataCite-RIS]
This property contains a string that is an identifier in the context of the identifier scheme referenced by its datatype.
0..1
4.16 Kind
Note
Class name
Kind
Obligation
Optional
URI
vcard:Kind
Usage note
A description following the [VCARD-RDF] specification, e.g. to provide telephone number and e-mail address for a contact point. Note that the class vcard:Kind is the parent class for the four explicit types of vCards (vcard:Individual, vcard:Organization, vcard:Location, vcard:Group).
This property contains an email address of the Kind, specified using fully qualified mailto: URI scheme [RFC6068].
0..1
+name
vcard:fn
rdfs:Literal
This property contains a name of the Kind. This property can be repeated for different versions of the name (e.g., the name in different languages) - see § 9. Accessibility and Multilingual Aspects.
0..1
+URL
vcard:hasURL
owl:Thing
This property points to a Web site of the Kind.
0..1
4.16.2 Optional properties for Kind
Note
Property
URI
Range
Usage note
Card.
+address
vcard:hasAddress
vcard:Address
This property MAY be used to specify the postal address of the Kind.
0..1
+affiliation
vcard:organization-name
rdfs:Literal
This property MAY be used to specify the affiliation of the Kind. This property can be repeated for different versions of the name (e.g. the name in different languages) - see § 9. Accessibility and Multilingual Aspects.
0..1
+phone
vcard:hasTelephone
owl:Thing
This property MAY be used to provide the phone number of the Kind, specified using fully qualified tel: URI scheme [RFC3966].
0..1
4.16.3 Examples for Kind
4.17 Licence Document
Class name
Licence Document
Obligation
Recommended
URI
dct:LicenseDocument
Usage note
A legal document giving official permission to do something with a resource.
This property refers to a type of licence, e.g. indicating ‘public domain’ or ‘royalties required’.
0..n
4.17.2 Optional property for Licence Document
Note
Property
URI
Range
Usage note
Card.
+licence text
rdfs:label
rdfs:Literal
This property contains the text of the Licence Document. This property can be repeated for parallel language versions of the name - see § 9. Accessibility and Multilingual Aspects.
0..n
4.17.3 Examples for Licence Document
4.18 Location
Class name
Location
Obligation
Optional
URI
dct:Location
Usage note
A spatial region or named place. It can be represented using a controlled vocabulary or with geographic coordinates.
rdfs:Literal typed as gsp:wktLiteral or gsp:gmlLiteral
This property refers to the geographic bounding box of a resource.
0..1
centroid
dcat:centroid
rdfs:Literal typed as gsp:wktLiteral or gsp:gmlLiteral
This property refers to the geographic centre (centroid) of a resource.
0..1
Note
4.18.2 Optional properties for Location
Note
Property
URI
Range
Usage note
Card.
+gazetteer
skos:inScheme
skos:ConceptScheme
This property MAY be used to specify the gazetteer to which the Location belongs.
0..1
+geographic identifier
dct:identifier
rdfs:Literal
This property contains the geographic identifier for the Location, e.g., the URI or other unique identifier in the context of the relevant gazetteer.
0..n
+geographic name
skos:prefLabel
rdfs:Literal
This property contains a preferred label of the Location. This property can be repeated for parallel language versions of the label - see § 9. Accessibility and Multilingual Aspects.
1..n
geometry
locn:geometry
rdfs:Literal typed as gsp:wktLiteral or gsp:gmlLiteral
This property associates any resource with the corresponding geometry.
An abridged version of the definition of these instances is shown in Example 18.
Instance
URI
Class
Usage note
+Spatial resolution as angular distance
geodcat:spatialResolutionAsAngularDistance
dqv:Metric
Spatial resolution expressed as angular distance [ISO-19115-1], by using a decimal degree.
+Spatial resolution as distance
geodcat:spatialResolutionAsDistance
dqv:Metric
Spatial resolution expressed as distance. It corresponds to the notion of spatial resolution as "ground distance" of [ISO-19115] and "horizontal ground distance" of [ISO-19115-1].
+Spatial resolution as equivalent scale
geodcat:spatialResolutionAsScale
dqv:Metric
Spatial resolution expressed as equivalent scale [ISO-19115], [ISO-19115-1], by using a representative fraction (e.g., 1:1,000, 1:1,000,000).
+Spatial resolution as vertical distance
geodcat:spatialResolutionAsVerticalDistance
dqv:Metric
Spatial resolution expressed as vertical distance [ISO-19115-1].
In GeoDCAT-AP, this property is typically used for Catalogues, Data Services, and Datasets. However, no domain restriction is defined, and therefore this property can be used on any resource.
4.20.2 Recommended properties for Metric
Note
Property
URI
Range
Usage note
Card.
+dimension
dqv:inDimension
dqv:Dimension
This property represents the dimensions a quality metric, certificate and annotation allow a measurement of.
In GeoDCAT-AP, this property is used in the definition of the instances of dqv:Metric corresponding to the different types of spatial resolution (see § 4.20.1 Instances of Metric). When used for this purpose, it MUST always take as value dqv:precision.
0..1
+expected data type
dqv:expectedDataType
rdfs:DataType
This property represents the expected data type for the Metric's observed value (e.g., xsd:boolean, xsd:double, etc.).
In GeoDCAT-AP, this property is used in the definition of the instances of dqv:Metric corresponding to the different types of spatial resolution (see § 4.20.1 Instances of Metric).
0..1
4.20.3 Examples for Metric
4.21 Period of Time
Class name
Period of time
Obligation
Optional
URI
dct:PeriodOfTime
Usage note
An interval of time that is named or defined by its start and end dates.
A statement of any changes in ownership and custody of a resource since its creation that are significant for its authenticity, integrity, and interpretation
4.22.1 Recommended property for Provenance Statement
Note
Property
URI
Range
Usage note
Card.
+provenance statement text
rdfs:label
rdfs:Literal
This property contains the text of the Provenance Statement. This property can be repeated for parallel language versions of the name - see § 9. Accessibility and Multilingual Aspects.
0..n
4.22.2 Examples for Provenance Statement
4.23 +Quality Measurement
Note
Class name
Quality Measurement
Obligation
Optional
URI
dqv:QualityMeasurement
Usage note
Represents the evaluation of a given resource (as a Data Service, Dataset, or Distribution) against a specific quality metric.
In GeoDCAT-AP, this class corresponds to the notion of "spatial resolution", as defined in [INSPIRE-MD-REG], [ISO-19115], and [ISO-19115-1].
4.23.1 Recommended properties for Quality Measurement
Note
Property
URI
Range
Usage note
Card.
+is measurement of
dqv:isMeasurementOf
dqv:Metric
This property indicates the Metric being observed.
In GeoDCAT-AP, this property is used to specify the type of spatial resolution being described, by taking as object one of the instances of dqv:Metric documented in § 4.20.1 Instances of Metric.
0..1
+unit of measure
sdmx-attribute:unitMeasure
skos:Concept
This property indicates the unit in which the data values are measured.
In GeoDCAT-AP, this property is used to specify, when relevant, the unit of measure of the spatial resolution being described, by taking as object the relevant term from the QUDT Units Vocabulary [QUDT-UNITS].
0..1
+value
dqv:value
rdfs:Literal
This property refers to values computed by the relevant Metric.
In GeoDCAT-AP, this property is used to specify the value of the spatial resolution being described via a typed literal. The datatype MUST correspond to the one specified via property dqv:expectedDataType in the definition of the corresponding instance of dqv:Metric.
0..1
4.23.2 Examples for Quality Measurement
4.24 Relationship
Class name
Relationship
Obligation
Optional
URI
dcat:Relationship
Usage note
An association class for attaching additional information to a relationship between DCAT Resources
This property refers to the function of an entity or agent with respect to another entity or resource.
1..n
relation
dct:relation
rdfs:Resource
This property refers to the resource related to the source resource.
1..n
4.25 Rights Statement
Note
Class name
Rights statement
Obligation
Optional
URI
dct:RightsStatement
Usage note
A statement about the intellectual property rights (IPR) held in or over a resource, a legal document giving official permission to do something with a resource, or a statement about access rights.
This property contains the text of the Rights Statement. This property can be repeated for parallel language versions of the name - see § 9. Accessibility and Multilingual Aspects.
0..n
4.26 Standard
Note
Class name
Standard
Obligation
Optional
URI
dct:Standard
Usage note
A standard or other specification to which a Catalogue, Catalogue Record, Data Service, Dataset, or Distribution conforms.
This property contains a free-text account of the Standard. This property can be repeated for parallel language versions of the description - see § 9. Accessibility and Multilingual Aspects.
0..n
+identifier
dct:identifier
rdfs:Literal
This property contains the main identifier for the Standard, e.g. the URI or other unique identifier in the context of the Catalogue, or of a reference register (e.g., the ISO, OGC, W3C catalogues of their standards, the OGC “EPSG coordinate reference systems” register [OGC-EPSG]).
0..n
+reference register
skos:inScheme
skos:ConceptScheme
This property MAY be used to specify the reference register to which the Standard belongs.
0..1
+release date
dct:issued
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the date of formal issuance (e.g., publication) of the Standard.
0..1
+title
dct:title
rdfs:Literal
This property contains a name given to the Standard. This property can be repeated for parallel language versions of the name - see § 9. Accessibility and Multilingual Aspects.
0..n
+type
dct:type
skos:Concept
This property refers to the type of the Standard. A controlled vocabulary for the values has not been established.
In GeoDCAT-AP, when the Standard is a spatial or temporal reference system, the relevant URIs from the INSPIRE glossary SHOULD be used [INSPIRE-GLOSSARY].
0..1
+version
owl:versionInfo
rdfs:Literal
This property contains a version number or other version designation of the Standard.
0..1
4.26.2 Optional properties for Standard
Note
Property
URI
Range
Usage note
Card.
+creation date
dct:created
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the date on which the Standard has been first created.
0..1
+update / modification date
dct:modified
rdfs:Literal typed as xsd:date or xsd:dateTime
This property contains the most recent date on which the Standard was changed or modified.
1..1
4.26.3 Examples for Standard
The following examples show the specification of different types of Standards.
5. Controlled Vocabularies
5.1 Requirements for controlled vocabularies
The following is a list of requirements that were identified for the controlled vocabularies to be recommended in this Application Profile.
Controlled vocabularies SHOULD:
Be published under an open licence.
Be operated and/or maintained by an institution of the European Union, by a recognised standards organisation or another trusted organisation.
Be properly documented.
Have labels in multiple languages, ideally in all official languages of the European Union.
Contain a relatively small number of terms (e.g. 10-25) that are general enough to enable a wide range of resources to be classified.
Have terms that are identified by URIs with each URI resolving to documentation about the term.
Have associated persistence and versioning policies.
These criteria do not intend to define a set of requirements for controlled vocabularies in general; they are only intended to be used for the selection of the controlled vocabularies that are proposed for this Application Profile.
5.2 Controlled vocabularies to be used
In the table below, a number of properties are listed with controlled vocabularies that MUST be used for the listed properties. The declaration of the following controlled vocabularies as mandatory ensures a minimum level of interoperability.
Compared with [DCAT-AP-20200608], GeoDCAT-AP makes use of additional controlled vocabularies mandated by [INSPIRE-MD-REG], and operated by the INSPIRE Registry - with the only exceptions of the coordinate reference systems register maintained by OGC [OGC-EPSG].
For two of these controlled vocabularies, namely the INSPIRE spatial data themes [INSPIRE-THEMES] and the ISO topic categories [INSPIRE-TC], the GeoDCAT-AP Working Group has defined a set of harmonised mappings to the EU Vocabularies Data Themes [EUV-THEMES], in order to facilitate the identification of the relevant theme in [EUV-THEMES] for geospatial metadata. The status of this work, along with links to a machine readable representation of the mappings, is documented on a dedicated page in Joinup [GeoDCAT-ACV].
The Corporate bodies NAL must be used for European institutions and a small set of international organisations. In case of other types of organisations, national, regional or local vocabularies should be used.
EU Vocabularies Continents Named Authority List [EUV-CONT], EU Vocabularies Countries Named Authority List [EUV-COUNTRIES], EU Vocabularies Places Named Authority List [EUV-PLACES], [GEONAMES]
The EU Vocabularies Name Authority Lists must be used for continents, countries and places that are in those lists; if a particular location is not in one of the mentioned Named Authority Lists, [GEONAMES] URIs must be used.
In addition to the proposed common vocabularies in § 5.2 Controlled vocabularies to be used, which are mandatory to ensure minimal interoperability, implementers are encouraged to publish and to use further region or domain-specific vocabularies that are available online. While those may not be recognised by general implementations of the Application Profile, they may serve to increase interoperability across applications in the same region or domain. Examples are the full set of concepts in EuroVoc [EUV-EUROVOC], the CERIF standard vocabularies [CERIF-VOCS], the Dewey Decimal Classification [DDC] and numerous other schemes.
For geospatial metadata, the working group has identified the following additional vocabularies:
Concerning licence vocabularies, implementers are encouraged to use widely recognised licences such as Creative Commons licences [CC], and in particular the CC Zero Public Domain Dedication [CC0] or CC-BY Attribution 4.0 International [CC-BY], or the Open Data Commons Public Domain Dedication and License (PDDL) [PDDL].
Often there is applicable legislation or a licency policy in place which determine the set of licences to be used. They may recommend the use of an open government licence such as the UK Open Government Licence [UKOGL].
Further activities in this area are undertaken by the Open Data Institute [ODI] with the Open Data Rights Statement Vocabulary [ODRS] and by the Open Digital Rights Language (ODRL) Initiative [VOCAB-ODRL].
6. Conformance
As well as sections marked as non-normative, all authoring guidelines, diagrams, examples, and notes in this specification are non-normative. Everything else in this specification is normative.
The key words MAY, MUST, MUST NOT, RECOMMENDED, SHOULD, and SHOULD NOT in this document
are to be interpreted as described in
BCP 14
[RFC2119] [RFC8174]
when, and only when, they appear in all capitals, as shown here.
6.1 Provider requirements
In order to conform to this Application Profile, an application that provides metadata MUST:
Provide information for the mandatory properties specified in § 4.7.1 Mandatory properties for Catalogue Record, if descriptions of Catalogue Records are provided – please note that the provision of descriptions of Catalogue Records is optional.
Provide descriptions of all organisations involved in the descriptions of Catalogue and Datasets, including at least the mandatory properties specified in § 4.4.1 Mandatory property for Agent.
Provide descriptions of all category schemes that contain the categories that are asserted in any of the descriptions of Datasets in the Catalogue, including at least the mandatory properties specified in § 4.9.1 Mandatory property for Category Scheme.
Provide descriptions of all categories involved in the descriptions of Datasets in the Catalogue, including at least the mandatory properties specified in § 4.8.1 Mandatory property for Category.
For the properties listed in the table in § 5.2 Controlled vocabularies to be used, the associated controlled vocabularies MUST be used. Additional controlled vocabularies MAY be used.
Recommended and optional classes may have mandatory properties, but those only apply if and when an instance of such a class is present in a description.
6.2 Receiver requirements
In order to conform to this Application Profile, an application that receives metadata MUST be able to:
As stated in § 2. Terminology used in the Application Profile, "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.).
7. Agent Roles
This section is non-normative.
GeoDCAT-AP supports the 11 agent roles defined in [INSPIRE-MD-REG] and [ISO-19115] by using two different but not mutually exclusive approaches.
In the first approach, roles are mapped to specific properties. In particular, GeoDCAT-AP makes use of the relevant properties from [DCAT-AP-20200608] and [DCTERMS], which overall cover 4 of the relevant roles - namely, dcat:contactPoint, dct:creator, dct:publisher, and dct:rightsHolder (not supported in [DCAT-AP-20200608]). The remaining 7 are covered by the corresponding properties defined in the GeoDCAT-AP namespace - namely, geodcat:custodian, geodcat:distributor, geodcat:originator, geodcat:principalInvestigator, geodcat:processor, geodcat:resourceProvider, and geodcat:user.
It is important to note that, following [INSPIRE-MD-REG] and [ISO-19115], in GeoDCAT-AP all these agent roles can be specified on Catalogues, Catalogue Records, Datasets, and Data Services.
The second and more general approach is based on [PROV-O], where agent roles are specified via a “qualified attribution” (prov:qualifiedAttribution). More precisely, the relevant Agent is specified via property prov:agent, whereas the role is specified with property dcat:hadRole, which takes as value a skos:Concept describing that role - as those included in the relevant code list operated by the INSPIRE Registry [INSPIRE-RPR]. This pattern is illustrated in Example 5.
The [PROV-O]-based approach is meant to give data providers an extension mechanism to specify, in a harmonised way, any kind of role, and, possibly, to attach additional information to the role and the associated Agent. As such, it MAY be used in combination with or to complement the property-based approach, but it MUST NOT replace it. For instance, it can be used to specify roles not covered by the agent role properties used in GeoDCAT-AP, and/or to specify additional information that cannot be expressed via a property (as the period during which an Agent covered a given role).
Following [INSPIRE-MD-REG] and [ISO-19115], GeoDCAT-AP supports the specification of test results to assess the degree of conformity of a resource (i.e., a Catalogue, a Dataset, a Data Service) with a given specification (e.g., a standard, a set of implementing rules, a set of data quality or interoperability criteria).
For this purpose, GeoDCAT-AP makes use of two different but not mutually exclusive approaches. More precisely, property dct:conformsTo is used when the test result states that a resource is conformant with a given specification. The more general approach is based on [PROV-O], and it specifies conformance test results as a testing activity (prov:Activity) that generates a result (specified with property prov:generated), corresponding to one of the degrees of conformity defined in [INSPIRE-MD-REG], and available from the INSPIRE Registry [INSPIRE-DoC]. The specification against which the testing activity is carried out is specified via a “qualified association” (prov:qualifiedAssociation), linked to a “plan” (prov:hadPlan) derived from (prov:wasDerivedFrom) the specification itself.
Accessibility in the context of this Application Profile is limited to information about the technical format of distributions of datasets. The properties dcat:mediaType and dct:format provide information that can be used to determine what software can be deployed to process the data. The accessibility of the data within the datasets needs to be taken care of by the software that processes the data and is outside of the scope of this Application Profile.
Multilingual aspects related to this Application Profile concern all properties whose contents are expressed as strings (i.e. rdfs:Literal) with human-readable text. Wherever such properties are used, the string values are of one of two types:
The string is free text. Examples are descriptions and labels. Such text may be translated into several languages.
The string is an appellation of a ‘named entity’. Examples are names of organisations or persons. These names may have parallel versions in other languages but those versions don’t need to be literal translations.
Wherever values of properties are expressed with either type of string, the property can be repeated with translations in the case of free text and with parallel versions in case of named entities. For free text, e.g. in the cases of titles, descriptions and keywords, the language tag is mandatory.
Language tags to be used with rdfs:Literal are defined by [BCP47], which allows the use of the "t" extension for text transformations defined in [RFC6497] with the field "t0" [CLDR] indicating a machine translation.
A language tag will look like: "en-t-es-t0-abcd", which conveys the information that the string is in English, translated from Spanish by machine translation using a tool named "abcd".
For named entities, the language tag is optional and should only be provided if the parallel version of the name is strictly associated with a particular language. For example, the name ‘European Union’ has parallel versions in all official languages of the union, while a name like ‘W3C’ is not associated with a particular language and has no parallel versions.
For linking to different language versions of associated web pages (e.g. landing pages) or documentation, a content negotiation [CONNEG] mechanism may be used whereby different content is served based on the Accept-Languages indicated by the browser. Using such a mechanism, the link to the page or document can resolve to different language versions of the page or document.
All the occurrences of the property dct:language, which can be repeated if the metadata is provided in multiple languages, must have a URI as their object, not a literal string from the [ISO-639] code list.
How multilingual information is handled in systems, for example in indexing and user interfaces, is outside of the scope of this Application Profile.
10. Privacy and security considerations
The GeoDCAT-AP vocabulary supports the attribution of data and metadata to various participants such as resource creators, publishers and other parties or agents, and as such defines terms that may be related to personal information. In addition, it also supports the association of rights and licenses with catalogued Resources and Distributions. These rights and licenses could potentially include or reference sensitive information such as user and asset identifiers as described in [VOCAB-ODRL].
Implementations that produce, maintain, publish or consume such vocabulary terms must take steps to ensure security and privacy considerations are addressed at the application level.
The ISA² Programme of the European Commission was represented by Pavlina Fragkou and Seth van Hooland.
Andrea Perego and Bert van Nuffelen were the editors of the specification.
Contributors: Andreas Kuckartz, Antonio Rotundo, Danny Vandenbroucke, Fabian Kirstein, Franck Cotton, Hannes Reuter, Jakub Klímek, James Passmore, Matthias Palmér, Riccardo Albertoni, Simon Cox.
This version of GeoDCAT-AP extends [DCAT-AP-20200608] with 6 additional classes and 69 additional properties (some of which re-used across classes). They are listed in the following table.
The objective of this work is to define an RDF syntax that can be used for the exchange of descriptions of spatial datasets, dataset series, and services among data portals. The RDF syntax should extend the DCAT Application Profile for data portals in Europe [DCAT-AP].
To provide an RDF syntax binding for the union of the elements in the INSPIRE metadata schema [INSPIRE-MD-REG], [INSPIRE-MD] and the core profile of ISO 19115:2003 [ISO-19115]. The guiding design principle is to make the resulting RDF syntax as simple as possible; thereby maximally using existing RDF vocabularies – such as the Dublin Core [DCTERMS] and [DCAT-AP] –, and as much as possible avoiding minting new terms. The defined syntax binding must enable the conversion of metadata records from ISO 19115 / INSPIRE to a harmonised RDF representation. The ability to convert metadata records from RDF to ISO 19115 / INSPIRE is not a requirement.
To update the reference XSLT implementation [GeoDCAT-XSLT] of the mappings defined in the GeoDCAT-AP specification.
To take into account and refer to alignment of relevant controlled vocabularies (e.g., the alignments between GEMET, INSPIRE themes, EuroVoc carried out by the Publications Office of the EU [EUV-EUROVOC]).
Additionally, the following outcomes may be achieved, outside the context of this specification:
To define new controlled vocabularies or define mappings between controlled vocabularies.
To define an RDF syntax binding for the elements in ISO 19115-1:2014 [ISO-19115-1].
B.2 Motivation and use cases
This section is non-normative.
The basic use case that GeoDCAT-AP intends to enable is a cross-domain data portal search for datasets, as documented in the DCAT-AP specification, version 2.0.1 [DCAT-AP-20200608]. GeoDCAT-AP will make it easier to share descriptions of spatial datasets between spatial data portals and general data portals, and thus help increase public and cross-sector access to such high value datasets. The datasets could include:
Datasets on the INSPIRE Geoportal
The INSPIRE Geoportal aggregates metadata for over 100k datasets across Europe. It provides the means to search for spatial data sets and spatial data services, and subject to access restrictions, to view spatial data sets from the EU Member States within the framework of the INSPIRE Directive. The metadata stored on this portal is structured according to the INSPIRE Metadata Technical Guidelines, version 2.0.1 [INSPIRE-MD-20170302]. In order to maximise visibility and re-use, spatial datasets could also be listed on general-purpose Open Data Portals, such as the European Union Open Data Portal (EU ODP) and the European Data Portal (EDP).
Datasets on national SDIs
GeoDCAT-AP would facilitate the integration of SDIs operated by EU Member States with any data catalogue able to consume [DCAT-AP]-compliant metadata.
General geospatial datasets
The geospatial community shares a common background and makes consistent use of consolidated standards and technologies. In particular, as far as metadata are concerned, it is widespread to use standards like [ISO-19115] / [ISO-19139], for the representation and encoding of metadata, and OGC’s [CSW] (Catalog Service for the Web) for accessing and querying metadata records. These standards are also those currently recommended in INSPIRE.
An additional RDF syntax for INSPIRE and ISO 19115 metadata elements is beneficial, especially when other data portals support the [DCAT-AP] metadata elements only.
Conversion rules to RDF syntax would allow Member States to maintain their collections of INSPIRE-relevant datasets following the INSPIRE Metadata Technical Guidelines [INSPIRE-MD], while at the same time publishing these collections on [DCAT-AP]-conformant data portals. A conversion to RDF syntax – using for example the GeoDCAT-AP XSLT script [GeoDCAT-XSLT] - allows additional metadata elements to be displayed on general-purposed data portals, provided that such data portals are capable of displaying additional metadata elements. Furthermore, data portals are frequently complemented by a triple store, making the full set of GeoDCAT-AP metadata queryable through a SPARQL endpoint [SPARQL11-QUERY].
B.3 Methodology and summary of results
This section is non-normative.
Methodologically, the development of GeoDCAT-AP implies three main interrelated tasks:
Definition of alignment criteria and requirements.
Identification of the metadata elements to be covered by GeoDCAT-AP.
Definition of alignments for the metadata elements to be covered by GeoDCAT-AP.
These tasks and their results are described in the following sections.
B.3.1 Alignment criteria and requirements
The overall objective of GeoDCAT-AP is twofold:
Provide a [DCAT-AP]-conformant representation of geospatial metadata.
Provide an as much as possible comprehensive RDF-based representation of geospatial metadata, based on widely used vocabularies, trying, at the same time, to avoid semantic loss and to promote cross-domain re-use.
Ensure backward compatibiliy with previous versions of GeoDCAT-AP.
GeoDCAT-AP must include, at least, all the mandatory [DCAT-AP] elements.
Vocabularies different from [DCAT-AP] can be used only for those geospatial metadata elements not supported in [DCAT-AP].
Another key criterion was to base as much as possible the defined alignments on existing practices, in particular those contributed by the GeoDCAT-AP WG. The objective was to build upon experiences having already addressed issues in scope of GeoDCAT-AP, and to avoid a negative impact on existing implementations.
Finally, as already mentioned in § B.1 Objectives, whenever no suitable candidates were available in existing vocabularies to represent geospatial metadata elements, the possibility of defining new terms was not excluded. However, this option needed to be carefully assessed, and discarded whenever it might have led to a specification that was conflicting with standards under preparation.
B.3.2 Metadata elements to be covered by GeoDCAT-AP
The general criterion used for this task was that GeoDCAT-AP would ideally cover all the metadata elements of the core profile of [ISO-19115] and those defined in INSPIRE, with the requirement that only optional elements MAY be excluded.
Based on this, the current version of GeoDCAT-AP covers the following set of metadata elements:
All the metadata elements in the core profile of [ISO-19115].
All the metadata elements defined in INSPIRE, with the exclusion of those not common to all the INSPIRE spatial data themes.
More precisely, the supported INSPIRE metadata elements include:
The set of metadata elements defined in the INSPIRE Metadata Regulation [INSPIRE-MD-REG].
The set of metadata elements defined in the INSPIRE Data and Services Regulation (Article 13: “Metadata required for Interoperability”) [INSPIRE-SDSS-REG]. These elements are also listed in Appendix C.3 to the INSPIRE Metadata Technical Guidelines (version 2.0.1) [INSPIRE-MD-20170302].
The set of metadata elements recommended as common to most of the INSPIRE spatial data themes in the INSPIRE Data Specifications Technical Guidelines, and listed in the first table included in Appendix C.7 to the INSPIRE Metadata Technical Guidelines (version 2.0.1) [INSPIRE-MD-20170302]. These elements are the following ones:
Maintenance information.
Conceptual and domain consistency (Data quality – Logical consistency).
The metadata elements not supported in the current version of GeoDCAT-AP are those recommended only for specific INSPIRE spatial data themes in the INSPIRE Data Specifications Technical Guidelines, and listed in Appendix C.7 to the INSPIRE Metadata Technical Guidelines (version 2.0.1) [INSPIRE-MD-20170302].
These elements have been excluded in the current version of GeoDCAT-AP for the following reasons:
The priority was to support all those elements relevant to any dataset.
These elements are all optional.
Support to these metadata elements might be provided in future versions of GeoDCAT-AP.
B.3.3 Alignments defined in GeoDCAT-AP
The alignments defined in the current version of GeoDCAT-AP are the result of an iterative revision process of [GeoDCAT-AP-20160802], following the criteria illustrated in the previous sections and the review of the GeoDCAT-AP WG. Alignments for [ISO-19115-1] have not been defined. § B.7 Comparison between INSPIRE and ISO 19115-1:2014 contains an overview of the most important changes with respect to [ISO-19115].
The work started with the review of [DCAT-AP-20200608], [VOCAB-DCAT-2], and [INSPIRE-MD-20170302], with the purpose of identifying possible disalignments of the mappings defined in [GeoDCAT-AP], as well as possible gaps in [DCAT-AP-20200608] and [VOCAB-DCAT-2], which may require the use of different vocabularies or the definition of new classes and/or properties in the GeoDCAT-AP namespace. In all these cases, backward compatibility with [GeoDCAT-AP-20160802] has been taken into account when implementing revisions.
Finally, the GeoDCAT-AP WG has worked in close coordination with the DCAT-AP WG, in order to ensure mutual compliance of the proposed solutions.
The results of this work, reflected in the current version of GeoDCAT-AP, can be summarised as follows:
Backward compatibility with [GeoDCAT-AP-20160802] is ensured: The revised mappings have been deprecated, but maintained in the mapping rules implemented in [GeoDCAT-XSLT] along with the new one, in the extended mapping profile of GeoDCAT-AP, and their support has been included in § 6. Conformance.
Compliance with [DCAT-AP-20200608] is ensured: The geospatial metadata elements covered by the defined mappings include all those that in [DCAT-AP-20200608] are mandatory, plus a subset of those that are recommended and optional.
The majority of the alignments defined in GeoDCAT-AP provide a complete representation of the corresponding geospatial metadata elements, but some metadata elements have open issues:
Partial mappings: For some metadata elements, only a partial mapping is available. This concerns data quality and maintenance information, for which only the mandatory components have been mapped (for more details, see § B.6.14 Conformity and data quality - *not in ISO 19115 core and § B.6.27 Maintenance information - *not in ISO 19115 core, respectively). This decision was taken because existing vocabularies did not offer the ability to represent all the components of these metadata elements.
The details of the alignments defined in GeoDCAT-AP are illustrated in the following section.
B.4 RDF syntax bindings for INSPIRE and ISO 19115 metadata elements
The following sections provide the list of the bindings defined in GeoDCAT-AP for the RDF representation of INSPIRE metadata and the core profile of [ISO-19115].
For detailed usage notes and examples of each of the metadata elements covered by GeoDCAT-AP, we refer the reader to § B.6 Detailed usage notes and examples (the relevant section is specified in the “comments” column of the mapping table).
B.4.1 Overview of bindings for GeoDCAT-AP Core
This section provides an overview of GeoDCAT-AP Core. This includes bindings for metadata elements of the INSPIRE metadata and metadata elements in the core profile of [ISO-19115] core for which DCAT-AP provides an RDF syntax binding. Those metadata elements for which [DCAT-AP-20200608] does not provide a binding are part of the GeoDCAT-AP Extended mapping profile described in § B.4.2 Overview of bindings for GeoDCAT-AP Extended.
GeoDCAT-AP Core is meant to enable the harvesting and re-use of spatial metadata records through [DCAT-AP-20200608]-conformant applications and services, including data portals and APIs. The alignments for INSPIRE and [ISO-19115] metadata elements that are not included in GeoDCAT-AP Core are defined in GeoDCAT-AP Extended, see § B.4.2 Overview of bindings for GeoDCAT-AP Extended.
In the following table, the starred elements (*) are used to indicate the corresponding metadata element in the core profile of [ISO-19115]. For each element, it is indicated whether the element is mandatory (M), optional (O), conditional (C), or recommended (R) in either specification.
See § B.6.4 Resource locator - *On-line resource. The defined encoding depends whether the resource is a service or a dataset or data series. Also, the value of the function code (CI_OnlineFunctionCode) is to be taken into account.
Keywords whose controlled vocabulary is the one of the INSPIRE spatial data themes are mapped to dcat:theme, and expressed by the corresponding URI in the INSPIRE Registry. See controlled vocabulary for theme in § 5.2 Controlled vocabularies to be used.
For services a syntax binding is provided in GeoDCAT-AP Extended only.
Geographic bounding box (M)
*Geographic location of the dataset (by four coordinates or by geographic identifier) (C)
B.4.2 Overview of bindings for GeoDCAT-AP Extended
This section provides an overview of the RDF syntax bindings in GeoDCAT-AP Extended. This GeoDCAT-AP mapping profile covers elements defined in INSPIRE and the core profile of [ISO-19115], for which [DCAT-AP-20200608] does not provide a syntax binding. GeoDCAT-AP Extended is a superset of GeoDCAT-AP Core.
The following table contains the defined RDF syntax binding for INSPIRE metadata. In the table below, the starred elements (*) are used to indicate the corresponding metadata element in the core profile of [ISO-19115]. For each metadata element, it is indicated whether the element is mandatory (M), optional (O), conditional (C), or recommended (R) in either specification.
Please note that some metadata elements have an RDF syntax binding in both the GeoDCAT-AP Core and Extended mapping profile. These elements fall in one of these categories:
Partial coverage by a [DCAT-AP-20200608] binding: This concerns conformity (only degree of conformity equal to “conformant” is supported) and responsible organisation (only responsible party roles creator, publisher, and point of contact are supported).
Subsumption by a GeoDCAT-AP RDF binding: ISO metadata elements available in GeoDCAT-AP Core, but for which only a many-to-one mapping is supported in [DCAT-AP-20200608]. This concerns resource types, since the [VOCAB-DCAT-2] notion of dataset encompasses both the ISO/INSPIRE notions of data set and data series.
In order to preserve the original semantics, the extended mapping profile of GeoDCAT-AP defines additional alignments to those included in GeoDCAT-AP Core. The two sets of alignments are not mutually exclusive, and can coexist without creating conflicts.
See § B.6.13 Spatial resolution – Spatial resolution of the dataset. Property dcat:spatialResolutionInMeters can only be used when spatial resolution is expressed as distance in metres. Property dqv:hasQualityMeasurement can be used to specify any type of spatial resolution. Property rdfs:comment is used only in case spatial resolution is specified as free-text.
B.5 Overview of metadata elements covered by GeoDCAT-AP
The following table provides an overview of the metadata elements in the INSPIRE metadata schema and in the core profile of [ISO-19115], and the available mappings in [DCAT-AP-20200608] and GeoDCAT-AP. Columns titled with “obligation” specify whether the corresponding metadata elements are mandatory (M), conditional (C), and optional (O) (where “conditional” means “mandatory under given conditions”).
Note that the mappings covered by [DCAT-AP-20200608] correspond to those defined in GeoDCAT-AP core, whereas those covered only by GeoDCAT-AP correspond to those defined in the GeoDCAT-AP extended.
INSPIRE
Obligation
ISO 19115 Core
Obligation
DCAT-AP
GeoDCAT-AP
Metadata point of contact
M
Metadata point of contact
M
Yes
Metadata date
M
Metadata date stamp
M
Yes
Yes
Metadata language
M
Metadata language
C
Yes
Yes
Metadata character set
C
Yes
Metadata file identifier
O
Yes
Metadata standard name
O
Yes
Metadata standard version
O
Yes
Resource title
M
Dataset title
M
Yes
Yes
Temporal reference - Date of creation / publication / last revision
C
Dataset reference date
M
Partially (creation date not included)
Yes
Resource abstract
M
Abstract describing the dataset
M
Yes
Yes
Resource language
C
Dataset language
M
Yes
Yes
Topic category
M
Dataset topic category
M
Yes
Geographic bounding box
M
Geographic location of the dataset (by four coordinates or by geographic identifier)
C
Yes
Yes
Character encoding
C
Dataset character set
C
Yes
Temporal reference - Temporal extent
C
Additional extent information for the dataset (vertical and temporal)
O
Partially (temporal extent only)
Partially (temporal extent only)
Lineage
M
Lineage
O
Yes
Yes
Spatial representation type
M
Spatial representation type
O
Yes
Encoding
M
Distribution format
O
Yes
Yes
Spatial resolution
C
Spatial resolution of the dataset
O
Yes (but only as horizontal ground distance)
Yes
Responsible organisation
M
Dataset responsible party
O
Partially (only 3 of the 11 responsible party roles are supported)
Yes
Resource locator
C
On-line resource
O
Yes
Yes
Coordinate reference system; Temporal reference system
M; C
Reference system
O
Yes
Conformity
M
Yes
Yes
Resource type
M
Yes
Yes
Spatial data service type
M
Yes
Keyword
M
Partially (only for datasets and dataset series)
Yes
Coupled resource
C
Yes
Yes
Unique resource identifier
M
Yes
Yes
Conditions for access and use
M
Yes
Yes
Limitations on public access
M
Yes
Yes
Maintenance information
O
Partially (only maintenance and update frequency)
Partially (only maintenance and update frequency)
Data quality – Logical consistency – Topological consistency
C
Partially (only conformance results)
Data quality – Logical consistency – Conceptual consistency
O
Partially (only conformance results)
Data quality – Logical consistency – Domain consistency
The content of the element ‘resource title’ can be represented in RDF as a plain literal, and by using property dct:title.
This binding may also include the specification of the language by using attribute @xml:lang [XML]. The language to be specified is the one indicated by element metadata language, mapped to the language identifiers defined by IETF BCP 47 [BCP47].
B.6.2 Resource abstract - *Abstract describing the dataset
The content of the elements ‘resource abstract’ can be represented in RDF as a plain literal, and by using property dct:description.
This binding may also include the specification of the language by using attribute @xml:lang [XML]. The language to be specified is the one indicated by element metadata language, mapped to the language identifiers defined by IETF BCP 47 [BCP47].
B.6.3 Resource type - *not in ISO 19115 core
Note
In [VOCAB-DCAT-2], the notion of dataset is quite broad, and may include both the INSPIRE notions of dataset and dataset series. Moreover, currently no existing vocabulary provides suitable candidates for the INSPIRE notions of dataset series – the existing ones are very generic (e.g., dctype:Collection is defined as An aggregation of resources [DCTERMS]).
Based on this, in GeoDCAT-AP both INSPIRE datasets and dataset series are specified as instances of dcat:Dataset.
Moreover, in order to maintain the INSPIRE distinction between datasets and dataset series, following the work on aligning INSPIRE Metadata and Dublin Core [INSPIRE-DC], in the extended mapping profile of GeoDCAT-AP they will be denoted by using the resource type code list operated by the INSPIRE Registry [INSPIRE-RT], and by using dct:type. More precisely, the following URIs SHOULD be used to denote, respectively, dataset and series:
As far as the INSPIRE notion of service is concerned, [VOCAB-DCAT-2] and [DCAT-AP-20200608] provide a specific class, namely, dcat:DataService, whereas class dcat:Catalog can be used to complement dcat:DataService for ‘discovery services’ in INSPIRE. Additionally, the spatial data service type can be specified by using dct:type with the corresponding code lists operated by the INSPIRE Registry [INSPIRE-SDST]. More precisely, the following URI SHOULD be used to denote services:
In INSPIRE, this element, quoting, defines the link(s) to the resource and/or the link to additional information about the resource. [VOCAB-DCAT-2] has a property, namely, dcat:landingPage, having exactly the same purpose.
[ISO-19115] offers however the ability to specify the “type” of resource locator by using a specific code list (CI_OnlineFunctionCode), described in the following table:
ISO 19115 – CI_OnlineFunctionCode
Description
download
online instructions for transferring data from one storage device or system to another
information
online information about the resource
offlineAccess
online instructions for requesting the resource from the provider
order
online order process for obtaining the resource
search
online search interface for seeking out information about the resource
Based on this, the mappings of element “resource locator” for data sets and data set series will vary depending on the function code (when available), based on the following table.
ISO 19115 – CI_OnlineFunctionCode
Property
Domain
Range
(not provided)
dcat:landingPage
dcat:Dataset
foaf:Document
download
dcat:accessURL
dcat:Distribution
rdfs:Resource
Information
foaf:page
dcat:Dataset
foaf:Document
offlineAccess
dcat:accessURL
dcat:Distribution
rdfs:Resource
order
dcat:accessURL
dcat:Distribution
rdfs:Resource
search
foaf:page
dcat:Dataset
foaf:Document
However, whenever the URL points to a service endpoint, the resource locator SHOULD be always mapped to property dcat:accessURL, and complemented by additional two properties, namely, dcat:endpointURL and dcat:endpointDescription.
More precisely, if the URL is recognised as pointing to a capabilities document, the URL is mapped to property dcat:endpointDescription, whereas property dcat:endpointURL will take as value the URL without it query string component.
Properties dcat:endpointURL and dcat:endpointDescription will have as domain class dcat:DataService, linked to the dataset distribution via property dcat:accessService.
Finally, whenever it is possible to recognise the service protocol, this information will be specified by property dct:conformsTo, taking as value the URI of the relevant specification from the INSPIRE Registry's code list for protocol values [INSPIRE-PV].
As far as services are concerned, the resource locator SHOULD be mapped to properties dcat:endpointURL, dcat:endpointDescription, and dct:conformsTo, as described above.
B.6.5 Unique resource identifier - *not in ISO 19115 core
In INSPIRE, this element is meant to uniquely identify a resource (dataset, series or service), and it is mandatory for datasets and series. It is specified by (a) a mandatory character string code and by (b) an optional character string namespace.
Based on [DCAT-AP-20200608], unique resource identifiers are mapped to dct:identifier (see Example 30). The actual value is obtained by the concatenation of the values of the namespace (if specified) and of the code in the original metadata record.
If the unique resource identifier is specified with or can be encoded as an HTTP URI, it can be used as the URI of the resource (see Example 31).
B.6.6 Coupled resource - *not in ISO 19115 core
Note
This element is used to link a service to the target datasets or dataset series.
Following [VOCAB-DCAT-2] and [DCAT-AP-20200608], this relationship is specified by using property dcat:servesDataset.
Note
The target dataset or series SHOULD be preferably referred to by using its unique resource identifier, as in Example 32.
B.6.7 Resource language and metadata language - *Dataset language and Metadata language
In INSPIRE metadata, metadata and resource languages (which may be different) are specified by using the three-letter language codes defined in [ISO-639-2].
Based on [DCAT-AP-20200608], both elements are specified with property dct:language, with the URI of the relevant language available from the relevant register operated by the EU Publications Office [EUV-LANG].
Example 33 assumes that the metadata language is Dutch, and the resource language is German.
The metadata language can be also used to specify the language of textual elements of resource metadata by using the @xml:lang attribute [XML].
Since @xml:lang takes as value language identifiers defined by IETF BCP 47 [BCP47], a mapping from the actual value of the metadata language is needed.
B.6.8 Topic category, originating controlled vocabulary, and keyword value - *Dataset topic category
In INSPIRE, these two elements have specific purposes. Quoting from the INSPIRE Metadata Regulation [INSPIRE-MD-REG] (§2.1 and §3.1, respectively):
The topic category is a high-level classification scheme to assist in the grouping and topic-based search of available spatial data resources.
The keyword value is a commonly used word, formalised word or phrase used to describe the subject. While the topic category is too coarse for detailed queries, keywords help narrowing a full text search and they allow for structured keyword search.
Moreover, two types of keywords are allowed:
free keywords;
keywords taken from a controlled vocabulary.
Finally, topic categories apply only to datasets and dataset series.
B.6.8.1 Topic category and keyword in datasets and dataset series
As far as dataset metadata are concerned, in both [VOCAB-DCAT-2] and [DCAT-AP-20200608], a distinction is made only between free keywords and keywords from controlled vocabularies, associated with a URI. For the former, dcat:keyword is used, whereas for the latter dcat:theme (which is a sub-property of dct:subject). Since the INSPIRE Registry operates URI registers for topic categories and INSPIRE spatial data themes, and in order to keep the distinction existing in INSPIRE between topic categories and keywords, the mapping is as follows:
Topic category is mapped to dct:subject, and expressed by the corresponding URIs minted for the ISO code list in the INSPIRE Registry – reference register:
Keywords associated with other controlled vocabularies are mapped to dcat:theme.
Following [DCAT-AP-20200608] recommendations, keywords from controlled vocabularies SHOULD be preferably specified with dereferenceable HTTP URIs. In such a case, the information concerning the originating controlled vocabulary can be omitted.
When keywords cannot be specified with HTTP URIs, they SHOULD be typed as a skos:Concept associated with a skos:ConceptScheme (used to type the originating controlled vocabulary), and annotated with the textual content and reference date(s) in the relevant INSPIRE metadata elements.
The representation of the information concerning the controlled vocabulary is illustrated in the following table.
Metadata Element
Proposed mapping
Originating controlled vocabulary
Title
skos:ConceptScheme
dct:title
Reference date
creation
dct:created
last revision
dct:modified
publication
dct:issued
For conformance with [DCAT-AP-20200608], GeoDCAT-AP records MUST also include keywords from the EU Vocabularies Data Theme Named Authority List [EUV-THEMES].
In order to ensure consistency, the relevant EU Vocabularies Data Theme keywords SHOULD be selected based on mappings with the controlled vocabularies used in INSPIRE / ISO 19115 metadata.
Note
B.6.8.2 Keyword in services
Note
As far as service metadata are concerned, keywords can classify either a service or the datasets / series operated by the service itself. For the latter, INSPIRE Metadata Regulation requires using at least one of the keywords from the ISO 19119 code list of spatial data service categories.
Both [VOCAB-DCAT-2] and [DCAT-AP-20200608] do not have any specific property for keywords classifying either a service or the datasets / series operated by a service. Moreover, dcat:theme and dcat:keyword cannot be used for services, since their domain is restricted to dcat:Dataset.
In order to keep the distinction between these two types of keywords, the adopted solution is as follows:
Keywords from the ISO 19119 codelists of spatial data service type and categories are mapped to dct:type, and expressed by the corresponding URI in the INSPIRE Registry – reference registers:
Keywords associated with other controlled vocabularies are mapped to dcat:theme. If not denoted by an HTTP URI, they SHOULD be expressed as a skos:Concept associated with a skos:ConceptScheme, and annotated with the textual content and reference date(s) in the relevant INSPIRE metadata elements.
B.6.9 Spatial data service type - *not in ISO 19115 core
B.6.10 Geographic bounding box - *Geographic location of the dataset (by 4 coordinates or by geographic identifier)
Note
In the core profile of [ISO-19115], spatial coverage can be specified either with a bounding box (a geometry) or a geographic identifier. INSPIRE is more restrictive, in that it requires using a bounding box
Based on that, GeoDCAT-AP specified spatial coverage as illustrated in the following sections.
B.6.10.1 Bounding box
As a general rule, when the area corresponding to the spatial coverage is denoted by a geometry, as in INSPIRE, [DCAT-AP-20200608] recommends the use of the Core Location Vocabulary [LOCN], where this is done by using property locn:geometry, having as range a geometry specified as
a URI - e.g., by using the geo URI scheme (IET RFC-5870) [RFC5870], or a geohash URI [GEOHASH], [GEOHASH-36];
a semantic representation - using vocabularies like W3C Lat/long [W3C-BASIC-GEO] or schema.org [SCHEMA-ORG].
However, in case the geometry is a bounding box or a centroid, properties dcat:bbox and dcat:centroid, respectively, SHOULD be used instead of locn:geometry.
It is worth noting that currently there is no agreement on a preferred format to be used in RDF for the representation of geometries. In GeoDCAT-AP, geometries can be provided in any, and possibly multiple, encodings, but at least one of the following must be made available: WKT or GML. An additional requirement concerns the coordinate reference system (CRS) used, which may vary on a country or territory basis. The CRS must be specified in the GML or WKT encoding as required by GeoSPARQL [GeoSPARQL]. Geometries shall be interpreted using the axis order defined in the spatial reference system used. For example, for CRS84 the axis order is longitude / latitude, whereas for WGS84 the axis order is latitude / longitude. Summarising:
Geometries MAY be provided in multiple encodings, but at least one of the following MUST be made available: GML and WKT.
For GML and WKT, the CRS MUST be specified as defined in GeoSPARQL [GeoSPARQL].
As geometries may be provided in multiple encodings, the corresponding datatype SHOULD be always specified to ensure that the geometry literal is correctly interpreted.
For GML and WKT, the [GeoSPARQL] datatypes gsp:gmlLiteral and gsp:wktLiteral, respectively, MUST be used.
For GeoJSON [RFC7946], datatype gsp:geoJSONLiteral, defined in the current draft of the new version of GeoSPARQL [GeoSPARQL11], SHOULD be used.
For the other geometry encodings, no datatype is currently available. Therefore, their interoperability is not ensured when metadata records are shared or harvested across catalogues.
Note
B.6.10.2 Geographic identifier
[ISO-19115] core also allows specifying the geographic location using a geographic identifier. Following [DCAT-AP-20200608], for this, it is RECOMMENDED to use an HTTP URI from one of the following registers / gazetteers:
The Named Authority Lists operated by the Metadata Registry of the EU Publications office concerning continents [EUV-CONT], countries [EUV-COUNTRIES], and places [EUV-PLACES].
If none of the above provides the relevant geographic identifiers, Geonames [GEONAMES] SHOULD be used.
If an HTTP URI is not available, the geographic identifier MUST be expressed with skos:prefLabel, and the reference to the originating controlled vocabulary (if any) MUST be specified with skos:inScheme. The controlled vocabulary will be described by a name (dct:title) and a last modified data (dct:modified).
As far as geographic identifiers are concerned, following [DCAT-AP-20200608], GeoDCAT-AP does not prevent the use other vocabularies in addition to the recommended ones. The vocabularies identified by the GeoDCAT-AP WG are listed in § 5.2 Controlled vocabularies to be used.
B.6.11 Temporal reference and metadata date –*Additional extent information for the dataset (vertical and temporal) and *Metadata date stamp
Note
Temporal reference is a composite element consisting of the following possible child elements:
temporal extent (temporal coverage);
date of publication, last revision, and/or creation.
Based on [DCAT-AP-20200608], temporal extent is mapped to dct:temporal, having as range dct:PeriodOfTime. The time instant or interval is specified by using properties dcat:startDate and dcat:endDate, respectively.
By contrast, date of publication, last revision, and creation are mapped, respectively, to dct:issued, dct:modified (both core and extended GeoDCAT-AP mapping profiles), and dct:created (only for the extended mapping profile of GeoDCAT-AP).
[DCAT-AP-20200608] does not have a property equivalent to the INSPIRE metadata element metadata date. In INSPIRE, this element is defined as follows (see [INSPIRE-MD-REG], Part B, §10.2):
The date which specifies when the metadata record was created or updated.
Due to this ambiguity, the defined mapping for this element is dct:modified.
B.6.12 Lineage - *Lineage
Following [DCAT-AP-20200608], this element is mapped to property dct:provenance.
Since the range of dct:provenance is not a literal, but class dct:ProvenanceStatement, the free-text content of element “lineage” can be expressed by using rdfs:label, as illustrated in [DC-UG-PM].
B.6.13 Spatial resolution – Spatial resolution of the dataset
Note
[VOCAB-DCAT-2] and [DCAT-AP-20200608] provide property dcat:spatialResolutionInMeters, to specify spatial resolution as distance in metres. Morever, [VOCAB-DCAT-2] and [SDW-BP] recommend the use of [VOCAB-DQV] to specify other types of spatial resolution, via property dqv:hasQualityMeasurement.
Based on this, GeoDCAT-AP specifies spatial resolution as follows:
Property dcat:spatialResolutionInMeters is used for spatial resolution when it is expressed as distance in metres.
Property dqv:hasQualityMeasurement is used for all types of spatial resolution. In such a case, the type of spatial resolution is specified by using property dqv:isMeasurementOf, which takes as value the relevant instance of class dqv:Metric defined in GeoDCAT-AP for this purpose (see § 4.20.1 Instances of Metric).
Property rdfs:comment is used when spatial resolution is specified as free-text.
The core mapping profile of GeoDCAT-AP, following [DCAT-AP-20200608], supports only the use property dcat:spatialResolutionInMeters, and, therefore, the other types of spatial resolution are left unmapped.
B.6.14 Conformity and data quality - *not in ISO 19115 core
In [ISO-19115], conformance and quality information is encoded as a quality report containing the result of a test (an evaluation) of a given quality measure, according to an evaluation method, with either a quantitative result (a metric) or a conformance result (pass or fail) as most important outcome.
The current version of GeoDCAT-AP only defines a syntax binding for conformity and not for data quality in general, making use of property dct:conformsTo and the W3C Provenance Ontology (PROV-O) [PROV-O], as explained in the following paragraphs.
[DCAT-AP-20200608] provides a single candidate, dct:conformsTo, which however can be used to map only a conformity of degree ‘conformant’. This is suitable for the core mapping profile of GeoDCAT-AP.
Considering how conformity must be expressed in extended mapping profile of GeoDCAT-AP (see [INSPIRE-MD-REG], Part B, §7), possible candidates are the W3C Evaluation and Report Language (EARL) [EARL10] and the W3C Provenance Ontology (PROV-O) [PROV-O]. The latter candidate was chosen by the GeoDCAT-AP Working Group, since it would enable wider re-use with respect to the EARL vocabulary, which is more specific, and its use is limited.
[PROV-O] allows encoding conformity as a test activity (prov:Activity) that generated a result specified with property prov:generated, corresponding to the degree of conformity, for which the INSPIRE Registry maintains a URI set [INSPIRE-DoC]. The specification against which the conformance is asserted is specified via a qualified association (prov:qualifiedAssociation) with a test plan (a prov:Plan) in turn derived from a standard (dct:Standard, also prov:Entity). These associations are made via a property chain: prov:qualifiedAssociation, prov:hadPlan, and prov:wasDerivedFrom.
This pattern is illustrated in the following table.
In order to grant interoperability with [DCAT-AP-20200608], when conformity is of degree “conformant”, the proposal is to use both [PROV-O] and dct:conformsTo for GeoDCAT-AP Extended.
B.6.15 Conditions for access and use and limitations on public access – Use limitation and access / other constraints
Note
In [DCAT-AP-20200608], licensing information is specified on (a) data catalogues (services) and on (b) the distribution(s) of a dataset, and not on the dataset itself. The principle is that different dataset distributions may be associated with different licensing terms. Moreover, [DCAT-AP-20200608] recommends the use of dct:accessRights for specifying access conditions.
Based on this, GeoDCAT-AP specifies use and access limitations by using, respectively, dct:license and dct:accessRights. These properties take as value the URI of the use / access limitations, when available. Otherwise, since the range of these properties is not a literal, but, respectively, classes dct:LicenseDocument and dct:RightsStatement, the free-text content of the corresponding ISO 19115 / INSPIRE metadata elements can be expressed by using rdfs:label, as illustrated in [DC-UG-PM].
Note
B.6.16 Responsible party and metadata point of contact - *Dataset responsible party and *Metadata point of contact
Note
[DCAT-AP-20200608] supports properties to denote the publisher, the creator, and the contact point for a dataset.
By contrast, [ISO-19115] and [INSPIRE-MD-REG] support 11 possible relationships between a resource (a dataset, a dataset series, a service) and an agent (organisation), plus one for metadata. However, for only some of them suitable candidates exist from widely used vocabularies (in particular, DCMI Metadata Terms [DCTERMS]).
In order to fill this gap, specific properties have been defined in the GeoDCAT-AP namespace to complement those available in [DCAT-AP-20200608] and [DCTERMS].
The following table lists the mappings between responsible party roles and the corresponding properties used in GeoDCAT-AP.
Party that accepts accountability and responsibility for the data and ensures appropriate care and maintenance of the resource.
geodcat:custodian
Owner
Part B, §6.3
Party that owns the resource.
dct:rightsHolder
User
Part B, §6.4
Party who uses the resource.
geodcat:user
Distributor
Part B, §6.5
Party who distributes the resource
geodcat:distributor
Originator
Part B, §6.6
Party who created the resource.
geodcat:originator
Point of contact
Part B, §6.7
Party who can be contacted for acquiring knowledge about or acquisition of the resource.
dcat:contactPoint
Principal investigator
Part B, §6.8
Key party responsible for gathering information and conducting research
geodcat:principalInvestigator
Processor
Part B, §6.9
Party who has processed the data in a manner such that the resource has been modified.
geodcat:processor
Publisher
Part B, §6.10
Party who published the resource
dct:publisher
Author
Part B, §6.11
Party who authored the resource.
dct:creator
The extended mapping profile of GeoDCAT-AP also supports the use of the W3C PROV ontology [PROV-O] and [VOCAB-DCAT-2] to specify the relationship between the resource and the responsible organisation. The FOAF Vocabulary [FOAF] is used to specify the contact information concerning the responsible party. Finally, the responsible party role will be specified by using dcat:hadRole, and using the relevant code list values from the INSPIRE Registry – reference register [INSPIRE-RPR]:
It is important to note that the [PROV-O]-based mappings are semantically equivalent to the property-based ones illustrated earlier in this section. Their use is therefore only accessory, and functional to possible requirements from the data provider side.
For these reasons, the GeoDCAT-AP overall approach is as follows:
Responsible parties and their roles MUST be represented by the corresponding properties, based on an agreed definition of 1-to-1 mappings.
The property-based representation MAY be complemented with the [PROV-O]-based approach.
As mentioned earlier, the latter option is supported only in the extended mapping profile of GeoDCAT-AP.
B.6.17 *Metadata file identifier
This element identifies a metadata record.
Metadata file identifiers are mapped to dct:identifier.
If the metadata file identifier is or can be encoded as an HTTP URI, it can also be used as the URI of the catalogue record (see Example 44).
B.6.18 *Metadata standard name, *Metadata standard version
Following [DCAT-AP-20200608], GeoDCAT-AP uses dct:conformsTo to specify the metadata standard, and properties dct:title and owl:versionInfo are used to specify the standard name and version, respectively.
This pattern is illustrated in the following table.
Metadata element
Proposed mapping
Metadata standard
Metadata standard name
dct:conformsTo (range dct:Standard)
dct:title
Metadata standard version
owl:versionInfo
Example 45 shows a GeoDCAT-AP metadata record obtained from one conformant with [ISO-19115].
To represent the standard name and version of the source ISO record, the GeoDCAT-AP metadata record must be extended as in Example 46.
B.6.23 Coordinate reference systems and Temporal reference systems – *Reference System
In GeoDCAT-AP, these elements are mapped to property dct:conformsTo. Moreover, in order to indicate that the object of dct:conformsTo denotes a reference system, an additional statement with predicate dct:type is added, with a code list value defining the notion of (spatial / temporal) reference system, taken from the glossary operated by the INSPIRE Registry [INSPIRE-GLOSSARY].
More precisely, the following URIs SHOULD be used to denote, respectively, spatial and temporal reference systems:
The reference system identifier SHOULD be preferably represented with an HTTP URI. In particular, spatial reference systems should be specified by using the corresponding URIs from the “EPSG coordinate reference systems” register operated by the Open Geospatial Consortium [OGC-EPSG].
In this register, the URI prefix for coordinate reference systems is the following one:
identifies coordinate reference system EPSG 4258, corresponding to ETRS89 (European Terrestrial Reference System 1989).
Note
In case the reference system is not specified as an HTTP URI, the mapping covers also other information included in the source metadata - as the identifier (dct:identifier), name (dct:title), and version (owl:versionInfo), plus a reference to the relevant register, if available (skos:inScheme). If a reference register is available, the reference system is implicitly also a skos:Concept, and its name can be specified by using skos:prefLabel.
Note
If not represented with an HTTP URI, the reference system identifier MUST be mapped to dct:identifier, as in Example 48.
B.6.24 Character encoding - *Dataset character set and *Metadata character set
In [VOCAB-DCAT-2] and [DCAT-AP-20200608], the specification of the character encoding of a dataset and the character encoding of a metadata record is not explicitly supported.
According to [RFC4288], the character set can be part of the media type specification, but only for type “text”. By contrast, in INSPIRE the character set can be specified also for other media types.
The W3C Content vocabulary [Content-in-RDF10] provides a possibly suitable candidate, namely, property cnt:characterEncoding, taking as value the character set names in the IANA register [IANA-CHARSETS]. GeoDCAT-AP uses this property.
Character encoding in [ISO-19115] metadata is specified with a code list that can be mapped to the corresponding codes in [IANA-CHARSETS], as shown in the following table (entries with 1-to-many mappings are in italic).
ISO 19115 - MD_CharacterSetCode
Description
IANA
ucs2
16-bit fixed size Universal Character Set, based on ISO/IEC 10646
ISO-10646-UCS-2
ucs4
32-bit fixed size Universal Character Set, based on ISO/IEC 10646
ISO-10646-UCS-4
utf7
7-bit variable size UCS Transfer Format, based on ISO/IEC 10646
UTF-7
utf8
8-bit variable size UCS Transfer Format, based on ISO/IEC 10646
UTF-8
utf16
16-bit variable size UCS Transfer Format, based on ISO/IEC 10646
UTF-16
8859part1
ISO/IEC 8859-1, Information technology - 8-bit single byte coded graphic character sets - Part 1 : Latin alphabet No.1
ISO-8859-1
8859part2
ISO/IEC 8859-2, Information technology - 8-bit single byte coded graphic character sets - Part 2 : Latin alphabet No.2
ISO-8859-2
8859part3
ISO/IEC 8859-3, Information technology - 8-bit single byte coded graphic character sets - Part 3 : Latin alphabet No.3
ISO-8859-3
8859part4
ISO/IEC 8859-4, Information technology - 8-bit single byte coded graphic character sets - Part 4 : Latin alphabet No.4
ISO-8859-4
8859part5
ISO/IEC 8859-5, Information technology - 8-bit single byte coded graphic character sets - Part 5 : Latin/Cyrillic alphabet
ISO-8859-5
8859part6
ISO/IEC 8859-6, Information technology - 8-bit single byte coded graphic character sets - Part 6 : Latin/Arabic alphabet
ISO-8859-6
8859part7
ISO/IEC 8859-7, Information technology - 8-bit single byte coded graphic character sets - Part 7 : Latin/Greek alphabet
ISO-8859-7
8859part8
ISO/IEC 8859-8, Information technology - 8-bit single byte coded graphic character sets - Part 8 : Latin/Hebrew alphabet
ISO-8859-8
8859part9
ISO/IEC 8859-9, Information technology - 8-bit single byte coded graphic character sets - Part 9 : Latin alphabet No.5
ISO-8859-9
8859part10
ISO/IEC 8859-10, Information technology - 8-bit single byte coded graphic character sets - Part 10 : Latin alphabet No.6
ISO-8859-10
8859part11
ISO/IEC 8859-11, Information technology - 8-bit single byte coded graphic character sets - Part 11 : Latin/Thai alphabet
ISO-8859-11
8859part13
ISO/IEC 8859-13, Information technology - 8-bit single byte coded graphic character sets - Part 13 : Latin alphabet No.7
ISO-8859-13
8859part14
ISO/IEC 8859-14, Information technology - 8-bit single byte coded graphic character sets - Part 14 : Latin alphabet No.8 (Celtic)
ISO-8859-14
8859part15
ISO/IEC 8859-15, Information technology - 8-bit single byte coded graphic character sets - Part 15 : Latin alphabet No.9
ISO-8859-15
8859part16
ISO/IEC 8859-16, Information technology - 8-bit single byte coded graphic character sets - Part 16 : Latin alphabet No.10
ISO-8859-16
jis
japanese code set used for electronic transmission
JIS_Encoding
shiftJIS
japanese code set used on MS-DOS machines
Shift_JIS
eucJP
japanese code set used on UNIX based machines
EUC-JP
usAscii
United States ASCII code set (ISO 646 US)
US-ASCII
ebcdic
IBM mainframe code set
IBM037
eucKR
Korean code set
EUC-KR
big5
traditional Chinese code set used in Taiwan, Hong Kong of China and other areas
Big5
GB2312
simplified Chinese code set
GB2312
B.6.25 Encoding - *Distribution format
In both [VOCAB-DCAT-2] and [DCAT-AP-20200608], this information is specified for the distribution(s) of a dataset, and not for the dataset itself.
Two properties are available:
dcat:mediaType: to be used when the format corresponds to one of the media types registered by IANA [IANA-MEDIA-TYPES].
dct:format: to be used in all the other cases, to be used with file type register operated by the Publications Office of the EU [EUV-FT].
The same approach is used in GeoDCAT-AP for ISO 19115 / INSPIRE metadata.
B.6.26 Spatial representation type – *Spatial representation type
In [ISO-19115], element “Spatial representation type” is meant mainly to describe the “method used to represent geographic information in the dataset”, by using a code list (see the table below).
The ADMS vocabulary [VOCAB-ADMS] includes a property, namely, adms:representationTechnique that could be used for this purpose. It is worth noting that, in the ADMS specification, adms:representationTechnique decribes a distribution, and not the dataset. Moreover, the [ISO-19115] code list of spatial representation types is available as a URI register from the INSPIRE Registry [INSPIRE-SRT].
Based on this, GeoDCAT-AP specifies this information by using property adms:representationTechnique, with the spatial representation type URIs operated by the INSPIRE Registry [INSPIRE-SRT].
This mapping is supported only in the extended mapping profile of GeoDCAT-AP.
The spatial representation types defined in [ISO-19115] are listed in the following table. It is important to note that, as stated in the INSPIRE Data Specifications, the only spatial representation types in scope of INSPIRE are the following ones: “vector”, “grid”, and “tin”.
ISO 19115 - MD_SpatialRepresentionTypeCode
Description
In scope of INSPIRE?
vector
vector data is used to represent geographic data
Yes
grid
grid data is used to represent geographic data
Yes
textTable
textual or tabular data is used to represent geographic data
No
tin
triangulated irregular network
Yes
stereoModel
three-dimensional view formed by the intersecting homologous rays of an overlapping pair of images
No
video
scene from a video recording
No
B.6.27 Maintenance information - *not in ISO 19115 core
In [ISO-19115], element “Maintenance information” is meant mainly to describe how frequently a resource is updated.
In [DCAT-AP-20200608], the update frequency is expressed through dct:accrualPeriodicity, with the frequency codes defined in the the EU Vocabularies Frequency Named Authority List [EUV-FREQ], which can be partially mapped to the ones used in [ISO-19115], as shown in the following table.
ISO 19115 - MD_MaintenanceFrequencyCode
Dublin Core Collection Description Frequency Vocabulary [CLD-FREQ]
EU Vocabularies Frequency Named Authority List [EUV-FREQ]
continual
continuous
UPDATE_CONT / CONT
daily
daily
DAILY
weekly
weekly
WEEKLY
fortnightly
biweekly
BIWEEKLY
monthly
monthly
MONTHLY
quarterly
quarterly
QUARTERLY
biannually
semiannual
ANNUAL_2
annually
annual
ANNUAL
asNeeded
-
-
Irregular
irregular
IRREG
notPlanned
-
-
unknown
-
UNKNOWN
-
triennial
TRIENNIAL
-
biennial
BIENNIAL
-
threeTimesAYear
ANNUAL_3
-
bimonthly
BIMONTHLY
-
semimonthly
MONTHLY_2
-
threeTimesAMonth
MONTHLY_3
-
semiweekly
WEEKLY_2
-
threeTimesAWeek
WEEKLY_3
-
-
OTHER
The [ISO-19115] code list of maintenance frequency codes is available as a URI register from the INSPIRE Registry [INSPIRE-MF].
Based on this, maintenance frequency is specified in GeoDCAT-AP by using dct:accrualPeriodicity with the EU Vocabularies Frequency Named Authority List [EUV-FREQ].
For the frequency codes not covered by the EU Vocabularies Frequency code list, the approach will be as follows:
In the core mapping profile of GeoDCAT-AP these codes will be ignored.
The extended mapping profile of GeoDCAT-AP will use the code list of ISO maintenance frequency codes operated by the INSPIRE Registry [INSPIRE-MF].
B.7 Comparison between INSPIRE and ISO 19115-1:2014
In [ISO-19115-1] the concept of ‘Core metadata’ was removed; it was translated into a normative annex (Annex F) “Discovery metadata for geographic resources”. In the Annex F metadata elements for the discovery are listed in 2 tables:
the metadata elements to be used for discovery of geographic datasets and series are identified in F.1;
the metadata elements to be used for discovery of service resources are identified in F.2.
B.7.1 Spatial dataset and spatial dataset series
The table below compares the core requirements of ISO 19115:2003 (see Table 3 in 6.5 of [ISO-19115]), the requirements of INSPIRE for spatial dataset and spatial dataset series as defined in the Implementing Rules for metadata and the discovery metadata for geographic datasets and series (see Table F.1 in annex F of [ISO-19115-1]). For those last metadata elements in the last field of the table the path is indicated. For each element, in brackets the obligation/max occurrence (3rd field).
ISO 19115 Core
INSPIRE Implementing Rules for Metadata
ISO 19115-1:2014 Discovery metadata for datasets and series (Table F.1)
MD_Metadata.identificationInfo > MD_Identification.spatialResolution > MD_Resolution.equivalentScaleMD_Resolution.distance, MD_Resolution.vertical, or MD_Resolution.angularDistance, or MD_Resolution.levelOfDetail
The table below compares the core requirements of ISO 19115:2003 (see Table 3 in 6.5 of ISO 19115:2003), the requirements of INSPIRE for services as defined in the Implementing Rules for metadata and the discovery metadata for services (see Table F.2 in annex F of ISO 19115-1:2014). For those metadata elements in the last field of the table the path is indicated. For each element, in brackets the obligation/max occurrence (3rd field).
ISO 19115 Core
INSPIRE
ISO 19115-1:2014 Discovery metadata for services (Table F.2)
C.1 Changes since first public working draft of 12 October 2020
Defined terms in the GeoDCAT-AP namespace (§ 4.20.1 Instances of Metric) for the specification of the different types of spatial resolution (see issue #15).
Defined properties in the GeoDCAT-AP namespace (§ 7. Agent Roles) for the specification of INSPIRE / ISO 19115:2003 responsible party roles not supported in [VOCAB-DCAT-2] and [DCTERMS] (see issue #32).
Adopted datatype gsp:geoJSONLiteral, defined in the current draft of GeoSPARQL [GeoSPARQL11], for GeoJSON literals, and deprecated the solution used in the previous versions of GeoDCAT-AP (see issue #4).
C.2 Changes since GeoDCAT-AP 1.0.1 (2 August 2016)
Document completely re-written starting from the [DCAT-AP-20200608] specification, with the purpose of using a consistent document structure across DCAT-AP specifications.
This property refers to the format of the file in which one or more data files are grouped together, e.g. to enable a set of related files to be downloaded together.
This property contains a description of the Data Services available via the endpoints, including their operations, parameters etc. The property gives specific details of the actual endpoint instances, while dct:conformsTo is used to indicate the general standard or specification that the endpoints implement.
This property indicates how long it is planned to keep the Distribution of the Dataset available. It MUST take one of the values: temporary, experimental, available, stable.
This property identifies the algorithm used to produce the subject Checksum. Currently, SHA-1 is the only supported algorithm. It is anticipated that other algorithms will be supported at a later time.
A value that allows the contents of a file to be authenticated. This class allows the results of a variety of checksum and cryptographic message digest algorithms to be represented.
Changed the recommendation to use new EU Data Theme vocabulary proposed by the Publications Office instead [EUV-THEMES] of EuroVoc [EUV-EUROVOC]. Added clarification that value is the URI of the concept scheme, not of the concepts.
Changed the recommendation to use terms from the new EU Data Theme vocabulary proposed by the Publications Office [EUV-THEMES] instead of EuroVoc domains [EUV-EUROVOC].
Changed the recommendation to use terms from the Frequency Name Authority List maintained by the Publications Office [EUV-FREQ] instead of the Dublin Core Collection Description Frequency Vocabulary [CLD-FREQ].