This specification defines a Profile of the W3C Data Catalog (DCAT) Vocabulary specifically for the use of describing Aeronautical datasets in the aviation industry. This DCAT Profile specification is a technical appendium to the ICAO Aeronautical Information Management (AIM) Manual Volume IV on Digital Data Sets. This manual provides the specific guidance for the provision of digital data sets that are managed and published by aeronautical data service providers.

The W3C DCAT recommendation enables a publisher to describe datasets and data services in a catalog using a standard model and vocabulary that facilitates the consumption and aggregation of metadata from multiple catalogs. This can increase the discoverability of datasets and data services. It also makes it possible to have a decentralized approach to publishing data catalogs and makes federated search for datasets across catalogs in multiple sites possible using the same query mechanism and structure.

Conformance

As well as sections marked as non-normative, all authoring guidelines, diagrams, examples, and notes in this Profile are non-normative. Everything else in this Profile is normative.

The key words MAY, MUST, MUST NOT, RECOMMENDED, SHOULD, and SHOULD NOT are to be interpreted as described in [[!RFC2119]].

Normative namespaces

Namespaces and prefixes used in normative parts of this Profile are shown in the following table.

Prefix	Namespace IRI	Source
`dcat`	`http://www.w3.org/ns/dcat#`	[[VOCAB-DCAT-3]]
`dct`	`http://purl.org/dc/terms/`	[[DCTERMS]]
`odrl`	`http://www.w3.org/ns/odrl/2/`	[[ODRL-VOCAB]]
`sdo`	`https://schema.org`	[[SCHEMA-ORG]]
`vcard`	`http://www.w3.org/2006/vcard/ns#`	[[VCARD-RDF]]

Syntax Serialisation

This Profile does not prescribe any particular method of deploying and encoding data catalogs expressed in DCAT. Within this Profile, the examples use [[JSON-LD]] because of its wide adoption.

URI Identifiers for Values

The DCAT specification, like most contemporary W3C recommendations, uses URIs as the value for many properties. This is consistent with Semantic Web and Linked Data principles.

This approach is new for the Aviation industry and as a tactical measure, this Profile will define a set of recommended URI values for relevant properties.

This Profile reserves the following URI domain for this purpose: http://vocab.icao.aero

The URIs based on this address will not be resolvable until a future time.

Where applicable, references will be made to existing online vocabularies with the same semantics.

ISO 19115 Mapping

A mapping currently exists between W3C DCAT and the Geographic Metadata ISO 19115 [[ISO-19115]] standard. The GeoDCAT Application Profile [[GEOCAT2]] provides the details in Appendix B of that document. Aeronautical data providers MAY require this conformance requirement.

Aeronautical Profile Model

The ICAO Aeronautical Information Management (AIM) Manual Volume IV on Digital Data Sets [[AIMV4]] defines the requirements for publishing digital data sets. This Profile defines how to implement these requirements as a Profile of the W3C DCAT specification [[VOCAB-DCAT-3]] The Aeronautical Dataset Profile model is shown in Figure 1. These classes, properties and relationships are considered to be the minimal standard and MUST be processable by conforming systems. Other classes, properties and relationships from [[!VOCAB-DCAT-3]] MAY be used but some consuming systems MAY not process the data fully.

Overview of DCAT Profile, showing the relevant classes, properties and relationships.

The Profile consists of the following six Classes:

Data Catalog (dcat:Catalog) - The collection of Aeronautical Dataset Series
Dataset Series (dcat:DatasetSeries) - A collection of related Aeronautical datasets
Data Product Specification (dcat:Resource) - A document describing a Dataset Series
Dataset (dcat:Dataset) - A collection of data related to a common Aeronautical feature
Data File (dcat:Distribution) - A specific data file representation of a Dataset
Data Service (dcat:DataService) - A digital interface that provides access to a Dataset

This Profile includes the following conformance rules:

The Data Catalog MAY be present
A Dataset Series MUST be present
A Data Product Specification MUST be present (for each Dataset Series)
A Dataset MUST be present (for each Dataset Series)
Either a Data File or a Data Service MUST be present (for each Dataset)

The formal definition of each property is as defined in [[!VOCAB-DCAT-3]] and is the normative reference. The following sections describes the additional contextual details for each property used in the above classes for use by Aeronautical datasets.

The examples in the following sections map the type of the above classes to @type in the JSON-LD serialisations

Identifier:	`dct:hasPart`
Notes:	The identifier of a Dataset Series in the Catalog

Describing the Dataset Series

Identifier

Identifier:	`dct:identifier`
Notes:	A unique URI of the Dataset Series. Mapped to `@id` in JSON-LD serialisations.

Title

Identifier:	`dct:title`
Notes:	Title of the Dataset Series

Description

Identifier:	`dct:description`
Notes:	Description of the Dataset Series

Theme

Identifier:	`dcat:theme`
Notes:	The theme/subject area the Dataset Series covers. The current set of URI values are defined below that covers the main themes for datasets in Aviation. Other URI values MAY be used.

http://vocab.icao.aero/AeronauticalInformation

Aeronautical information of lasting character essential to air navigation

http://vocab.icao.aero/AirportMapping

Collection of aerodrome mapping data organized and arranged as structured data

http://vocab.icao.aero/InstrumentFlightProcedure

A series of predetermined flight manoeuvres by reference to flight instruments

http://vocab.icao.aero/Obstacle

All fixed and mobile objects that have been assessed as being a hazard to air navigation

http://vocab.icao.aero/Terrain

The surface of the Earth containing naturally occurring features

Same As: https://schema.org/Landform

Policy

Identifier: odrl:hasPolicy

Notes:

Defines specific usage rules applicable to all the Datasets in the Dataset Series. This property uses the W3C ODRL Policy language [[ODRL-MODEL]] to describe the usage policy. ODRL supports the ability to define actions that are permitted or prohibited. In addition, obligations can also be defined.

There is only one use case identified for Aviation datasets that is the use of the dataset(s) is for non-operational purposes only. This can be expressed as a prohibition of the (positive) action of operational use. The URI required to meet this use case is defined below.

http://vocab.icao.aero/OperationalUse

Intended to be used as the basis for operational decision making

Spatial

Identifier: dct:spatial

Notes:

The spatial area the Dataset Series covers.

There are three types of spatial locations supported:

State - The name and ICAO code for the State. Also MAY include the name of the territory/jurisdiction within the State.
Aerodrome - The name and the ICAO or IATA code for the aerodrome
Airspace - The name, designator code, and category of the airspace.

Each of the above spatial types will define a type URI (which will be equivalent to dct:Location) as well as the set of properties to describe the location. These type URIs are defined below.

The properties to describe the State location are:

vcard:country-name for text-based country name or vcard:hasCountryName for a URI identifying the country.
vcard:region for text-based territory/jurisdiction name or vcard:hasRegion for a URI identifying the territory/jurisdiction.
sdo:termCode for the ICAO code of the State

The properties to describe the Aerodrome location are:

sdo:name for the name of the aerodrome
sdo:icaoCode for the ICAO code identifying the aerodrome
sdo:iataCode for the IATA code identifying the aerodrome

The properties to describe the Airspace location are:

sdo:name for the name of the airspace
sdo:codeValue for the designator code identifying the airspace
sdo:termCode for the category of airspace

http://vocab.icao.aero/State

An internationally recognised geographic entity that provides aeronautical information service

Same As: https://schema.org/AdministrativeArea

http://vocab.icao.aero/Aerodrome

A defined area on land or water intended to be used either wholly or in part for the arrival, departure and surface movement of aircraft

Same As: https://schema.org/Airport

http://vocab.icao.aero/Airspace

A defined three dimensional region of space relevant to air traffic

Part of Catalog

Identifier:	`dct:isPartOf`
Notes:	The identifier of a Catalog that this Dataset Series is a part of

Has Dataset

Identifier:	`dcat:dataset`
Notes:	The identifier of a Dataset in this Dataset Series

Referenced By

Identifier:	`dct:isReferencedBy`
Notes:	The identifier of the Data Product Specification description that covers this Dataset Series

Example

The example below describes the Aeronautical Information Package (AIP) Dataset Series in the Donlon Catalogue. The hasPolicy permits operational use. If the opposite was required, then the odrl:Permission should be changed to odrl:Prohibition. For demonstrable purposes, the example includes all three spatial location types. Only one type would appear in real instances. The example links to four explicit datasets in this series.

    {
      "@id": "http://donlon.aero/series/aip",
      "@type": "dcat:DatasetSeries",
      "dct:title": "Donlon AIP Series",
      "dct:description": "AIP datasets for Donlon ...",
      "dcat:theme": "http://vocab.icao.aero/AeronauticalInformation",
      "odrl:hasPolicy": {
        "@type": "odrl:Permission",
        "odrl:action": "http://vocab.icao.aero/OperationalUse" },
      // Example State spatial location
      "dct:spatial": {
          "@type": "http://vocab.icao.aero/State",
          "vcard:country-name": "Republic of Donlon",
          "vcard:region": "South Donlon",
          "sdo:termCode": "DDDD" },
      // Example Aerodrome spatial location
      "dct:spatial": {
          "@type": "http://vocab.icao.aero/Aerodrome",
          "sdo:name": "Donlon International Airport",
          "sdo:icaoCode": "ZZZZ",
          "sdo:iataCode": "ZZZ" },
      // Example Airspace spatial location
      "dct:spatial": {
          "@type": "http://vocab.icao.aero/Airspace",
          "sdo:name": "AMSWELL",
          "sdo:codeValue": "EAAD",
          "sdo:termCode": "FIR" },
      "dct:isPartOf": "http://donlon.aero/data-catalogue",
      "dct:dataset": ["http://donlon.aero/series/aip/2021/Jan",
                      "http://donlon.aero/series/aip/2021/Feb",
                      "http://donlon.aero/series/aip/2021/Mar",
                      "http://donlon.aero/series/aip/2021/Apr"],
      "dct:isReferencedBy": "http://donlon.aero/product/aip-series"
    }

Describing the Dataset

Identifier

Identifier:	`dct:identifier`
Notes:	A unique URI of the Dataset. Mapped to `@id` in JSON-LD serialisations.

Title

Identifier:	`dct:title`
Notes:	Title of the Dataset

Description

Identifier:	`dct:description`
Notes:	Description of the Dataset

Type

Identifier:	`dct:type`
Notes:	The release type of the Dataset. The current set of URI values are defined below for the types of dataset releases. Other URI values MAY be used.

http://vocab.icao.aero/Dataset/Baseline

The dataset includes all features

http://vocab.icao.aero/Dataset/Snapshot

The dataset includes all features at a specified time instance

http://vocab.icao.aero/Dataset/DeltaPerm

The dataset includes all feature permanent differences

http://vocab.icao.aero/Dataset/DeltaTemp

The dataset includes all feature temporary differences

Theme

Identifier:	`dcat:theme`
Notes:	The theme/subject area the Dataset Series covers. Note that the Dataset theme MUST not conflict with any theme defined for the parent Dataset Series. The current set of URI values are defined in Section 4.4 Theme. Other URI values MAY be used.

Method

Identifier:	`dct:accrualMethod`
Notes:	The methodology used for items added to the dataset. Used to indicate if the dataset was published as part of the AIRAC (Aeronautical Information Regulation And Control) cycle. The current set of URI values are defined below for the types of dataset releases. Other URI values MAY be used.

http://vocab.icao.aero/Dataset/AIRAC

The dataset is published under the AIRAC cycle

Conformance

Identifier:	`dct:conformsTo`
Notes:	The technical encoding/serialisation of the dataset contents. The current set of URI values are defined below for technical conformance. Other URI values MAY be used.

http://vocab.icao.aero/AIXM

The dataset conforms to the AIXM specification

http://vocab.icao.aero/FIXM

he dataset conforms to the FIXM specification

http://vocab.icao.aero/IWXXM

The dataset conforms to the IWXXM specification

http://vocab.icao.aero/AMXM

The dataset conforms to the AMXM specification

Policy

Identifier:	`odrl:hasPolicy`
Notes:	Defines specific usage rules applicable to the Dataset. Note that the Dataset rules MUST not conflict with any policy defined for the parent Dataset Series. See Section 4.5 Policy for more details.

Issued

Identifier:	`dct:issued`
Notes:	The date of issue of the Dataset. MAY include the time in the date.

Temporal

Identifier:	`dct:temporal`
Notes:	The effective dates related to Dataset. MUST include at least one of `dct:startDate` or `dct:endDate`. MAY includes the times in the dates.

Spatial

Identifier:	`dct:spatial`
Notes:	The spatial area the Dataset covers. Note that the Dataset spatial location MUST not conflict with any spatial location defined for the parent Dataset Series. See Section 4.6 Spatial for more details.

Part of Dataset Series

Identifier:	`dct:isPartOf`
Notes:	The identifier of a Dataset Series that this Dataset is a part of

Has Distribution

Identifier:	`dcat:distribution`
Notes:	The identifier of the distribution describing how to download the dataset file

Has Service

Identifier:	`dcat:service`
Notes:	The identifier of the data service describing how to access the dataset file

Example

The example below describes the Aeronautical Information Package (AIP) Dataset for April 2021. The example includes links to both a file distribution and a data service to access the dataset (see the following sections for description of their properties).

      {
        "@id": "http://donlon.aero/series/aip/2021/Apr",
        "@type": "dcat:Dataset",
        "dct:title": "Donlon AIP Dataset April 2021",
        "dct:description": "AIP dataset for Donlon ...",
        "dct:type": "http://vocab.icao.aero/Dataset/Baseline",
        "dcat:theme": "http://vocab.icao.aero/AeronauticalInformation",
        "dct:accuralMethod": "http://vocab.icao.aero/Dataset/AIRAC",
        "dct:conformsTo": "http://vocab.icao.aero/AIXM",
        "dct:issued": "2021-03-25",
        "dct:temporal": {
           "@type": "dct:PeriodOfTime", 
           "dct:startDate": "2021-04-01", 
           "dct:endDate": "2021-04-30" },
        "dct:spatial": {
           "@type": "http://vocab.icao.aero/State",
           "vcard:country-name": "Republic of Donlon",
           "sdo:termCode": "DDDD" },
        "dct:isPartOf": "http://donlon.aero/series/aip",
        "dcat:distribution": {
           "@type": "dcat:Distribution",
           "dcat:downloadURL": "http://donlon.aero/series/aerodrome/2021/Jan/data.xml", 
           "dcat:mediaType": "https://www.iana.org/assignments/media-types/application/gml+xml",
           "dcat:byteSize": "34254" },
        "dcat:service": {
           "@type": "dcat:DataService",
           "dcat:endpointURL": "http://donlon.aero/data-api/aip/",
           "dcat:compressFormat": "https://www.iana.org/assignments/media-types/application/gzip" }
      }

Identifier:	`dcat:downloadURL`
Notes:	The URI to directly download the dataset file

Identifier:	`dcat:mediaType`
Notes:	The media type of the file distribution. This property SHOULD use media types defined by IANA [[IANA-MEDIA-TYPES]]

Identifier:	`dcat:byteSize`
Notes:	The size of the distribution in bytes

Identifier:	`dcat:endpointURL`
Notes:	The primary endpoint URI of the data service

Identifier:	`dcat:packageFormat`
Notes:	The package format of the dataset in which one or more data files are grouped together. The format SHOULD be expressed using a media type as defined by IANA [[IANA-MEDIA-TYPES]]

Identifier:	`dcat:compressFormat`
Notes:	The compression format of the dataset in which the data is contained in a compressed form. The format SHOULD be expressed using a media type as defined by IANA [[IANA-MEDIA-TYPES]]

Describing the Data Product Specification

Identifier

Identifier:	`dct:identifier`
Notes:	A unique URI of the Data Product Specification description. Mapped to `@id` in JSON-LD serialisations.

Title

Identifier:	`dct:title`
Notes:	The title of the Data Product Specification.

Document Type

Identifier:	`dct:type`
Notes:	The type of document. This property is used to assert that the resource is a Data Product Specification. The URI is defined below.

http://vocab.icao.aero/DataProductSpecification

The resource is of type Data Product Specification

References

Identifier:	`dct:references`
Notes:	The identifier of the Dataset Series this Data Product Description covers

Has distribution

Identifier:	`dcat:distribution`
Notes:	The identifier of the distribution describing how to access the document.

Example

The example below describes a Data Product Description for the Donlon AIP Dataset Series

  {
    "@id": "http://donlon.aero/product/aip-series",
    "@type": "dcat:Resource",
    "dct:title": "Donlon AIP Dataset Series Product Description",
    "dct:type": "http://vocab.icao.aero/DataProductSpecification",
    "dct:references": "http://donlon.aero/series/aip",
    "dcat:distribution": {
      "@type": "dcat:Distribution",
      "dcat:downloadURL": "http://donlon.aero/dps/aip.pdf", 
      "dcat:mediaType": "https://www.iana.org/assignments/media-types/application/pdf" }
  }

W3C DCAT Profile for ICAO Aeronautical Datasets

Status of this document

Conformance

Normative namespaces

Syntax Serialisation

URI Identifiers for Values

ISO 19115 Mapping

Aeronautical Profile Model

Describing the Data Catalog

Identifier

Title

Description

Has Dataset Series

Example

Describing the Dataset Series

Identifier

Title

Description

Theme

Policy

Spatial

Part of Catalog

Has Dataset

Referenced By

Example

Describing the Dataset

Identifier

Title

Description

Type

Theme

Method

Conformance

Policy

Issued

Temporal

Spatial

Part of Dataset Series

Has Distribution

Has Service

Example

Describing the Data File Distribution

Access

Media Type

Media Size

Describing the Data Service

Endpoint

Package Format

Compression Format

Describing the Data Product Specification

Identifier

Title

Document Type

References

Has distribution

Example

Acknowledgements