era-resource-uri-minting

name	era-resource-uri-minting
description	Mint correct URIs for ERA resource instances. Use when writing any BIND(IRI(...)) expression, choosing an ontology module path, or deciding whether to use the ERA namespace or a data provider namespace.

ERA Resource URI Minting

URI structure

http://data.europa.eu/949/[ontology-module]/{class-name}/{data-id}

• [ontology-module] — optional; official values: topology, trackside, onboard, body
• {class-name} — lowerCamelCase singular (e.g., operationalPoint, sectionOfLine)
• {data-id} — alphanumeric; only - and _ as separators; no spaces, /, ., (, ), #, or %20

Valid: http://data.europa.eu/949/topology/linearElement/26489401-SVN
Invalid: http://data.europa.eu/949/operationalPoints/ATAh%20H1K (encoded space)

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Common ERA URI patterns

The official [ontology-module] values are topology, trackside, onboard, body. Some implementations use alternative module names (e.g., infrastructureElement instead of trackside) — this is acceptable provided URIs are consistent within the dataset.

Topology module

Class	Pattern
LinearElement	topology/netElements/{id}
NetRelation	topology/netRelations/{id}
NetLinearReference	topology/netLinearReferences/{elementId}_{order}
NetPointReference	topology/netPointReferences/{elementId}_{order}_{start|end}
TopologicalCoordinate	topology/topologicalCoordinates/{elementId}_{order}_{start|end}
rdf:List node	topology/netLinearReferences/{elementId}_{order}_{nodeOrder}

Infrastructure Element module

Class	Pattern
Track	infrastructureElement/tracks/{id}
OperationalPoint	infrastructureElement/operationalPoints/{id}
SectionOfLine	infrastructureElement/sectionsOfLine/{id}
Signal	infrastructureElement/signals/{id}
Switch	infrastructureElement/switches/{id}
LevelCrossing	infrastructureElement/levelCrossings/{id}
ContactLineSystem	infrastructureElement/contactLineSystems/{id}
ETCS	infrastructureElement/etcs/{id}
PlatformEdge	infrastructureElement/platformEdges/{id}

Geometry

• Net element geometry: http://data.europa.eu/949/geometry/netElement_{id}
• Enriched geometry: http://data.europa.eu/949/geometry/{geomType}/{sha256hash8} (deterministic; SHA-256 of WKT, first 8 chars)

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SPARQL BIND pattern

BIND(IRI(CONCAT("http://data.europa.eu/949/infrastructureElement/tracks/", ?trackId)) AS ?eraTrack)

For composite keys, use _ as separator:

BIND(IRI(CONCAT("http://data.europa.eu/949/topology/netLinearReferences/", str(?trackId), "_", str(?order))) AS ?netLinearRef)

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Data provider namespace

ERA allows data providers to mint URIs in their own namespace instead of http://data.europa.eu/949/. The provider choices their own template.

Requirement: own-namespace URIs MUST be dereferenceable — an HTTP GET on the URI must return a valid response. This is a Linked Data requirement; non-resolvable URIs are not acceptable.

Dereferenceable URIs SHOULD support content negotiation:

Accept header	Expected response
text/html	Human-readable HTML page describing the resource
text/turtle or application/rdf+xml or application/ld+json	RDF description of the resource

GET https://data.mycompany.eu/_infrastructure_tracks_TRK-001
Accept: text/turtle

→ 200 OK  (or 303 See Other redirect to a document URI)
Content-Type: text/turtle

<https://data.mycompany.eu/_infrastructure_tracks_TRK-001>
    a era:Track ;
    era:trackId "TRK-001" .

Use own-namespace URIs when:

• Data is not to be merged into the official ERA Knowledge Graph
• The data provider manages their own URI lifecycle and can guarantee HTTP resolution

Own-namespace IDs follow the same {data-id} character restrictions (no spaces, ., (, ), #).

Opinion

The personal opinion of the author is that:

• the data provider should mint their own URIs in their own namespace
• the URI template uses a domain that produces a limited amount of PREFIX declarations. That would mean no /ontology-module/class-name/ path segments, but instead a flatter structure like http://data.mycompany.eu/_ontology-module_class-name_id.