railml-sparql-construct

name	railml-sparql-construct
description	Create SPARQL CONSTRUCT queries to transform railML 3.2 XML to ERA ontology RDF following project conventions. Use when implementing new infrastructure element mappings or updating existing CONSTRUCT queries.

railML to ERA SPARQL CONSTRUCT Implementation

Create SPARQL CONSTRUCT queries following established project patterns for transforming railML 3.2 XML data to ERA ontology RDF.

File Location Pattern

advanced-example/02-construct/03-functional-infrastructure/NN-element-name.sparql

Standard Prefixes

PREFIX era: <http://data.europa.eu/949/>
PREFIX country: <http://data.europa.eu/949/countries/>
PREFIX gsp: <http://www.opengis.net/ont/geosparql#>
PREFIX railml: <https://www.railml.org/schemas/3.2#>
PREFIX xyz: <http://sparql.xyz/facade-x/data/>
PREFIX fx: <http://sparql.xyz/facade-x/ns/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>

Query Structure Template

# Phase 3.N — Element Name (functional infrastructure)
# Maps railml:SourceElement → era:TargetClass
#
# Source: N railML instances
# 
# Target properties:
#   - era:property1 — description (type, cardinality)
#   - era:property2 — description
#
# URI Pattern:
#   http://data.europa.eu/949/functionalInfrastructure/elementType/{id}

CONSTRUCT {
  # Main resource and type
  ?eraElement a era:TargetClass ;
              rdfs:label ?label ;
              era:property1 ?value1 ;
              era:property2 ?value2 .
}
WHERE {
  # Get railML source elements
  ?railmlElement a railml:SourceElement ;
                 xyz:id ?elementId .
  
  # Mint ERA URI
  BIND (IRI(CONCAT("http://data.europa.eu/949/functionalInfrastructure/elementType/", ?elementId)) AS ?eraElement)
  
  # Extract properties
  # ...
}

Class Hierarchy Check: InfrastructureElement

CRITICAL STEP: Before applying any positioning pattern, verify if the target ERA class is a subclass of era:InfrastructureElement.

Check Subclass Relationship (MCP Query)

PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX owl: <http://www.w3.org/2002/07/owl#>
PREFIX era: <http://data.europa.eu/949/>

SELECT ?class ?superClass
WHERE {
  era:YourClass rdfs:subClassOf* ?superClass .
  
  # Filter out deprecated classes
  FILTER NOT EXISTS { ?superClass owl:deprecated "true"^^xsd:boolean }
}

Decision Tree:

1. IF class is subclass of era:InfrastructureElement:

   • ✅ Use era:netReference property
   • ✅ Create NetLinearReference, NetPointReference, or NetAreaReference
   • Examples: Track, Bridge, Signal, Switch, OperationalPoint, PlatformEdge

2. IF class is NOT subclass of era:InfrastructureElement:

   • ❌ Do NOT use era:netReference property
   • ✅ Class is a "functional resource" referenced FROM infrastructure elements
   • ✅ Find which InfrastructureElement classes reference this resource
   • ✅ Create linking via shared netElements in railML data
   • Examples: ContactLineSystem, TrainDetectionSystem, LoadingGaugeProfile, TrackGaugeProfile

Discovery of Linking Property (for non-InfrastructureElements)

PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX owl: <http://www.w3.org/2002/07/owl#>
PREFIX era: <http://data.europa.eu/949/>

SELECT ?property ?domain
WHERE {
  ?property rdfs:range era:YourFunctionalResourceClass .
  OPTIONAL { ?property rdfs:domain ?domain . }
  
  # Filter out deprecated properties
  FILTER NOT EXISTS { ?property owl:deprecated "true"^^xsd:boolean }
}

Then check SHACL shapes to confirm which classes have this property:

PREFIX sh: <http://www.w3.org/ns/shacl#>
PREFIX era: <http://data.europa.eu/949/>

SELECT ?targetClass ?property
WHERE {
  ?shape sh:targetClass ?targetClass .
  ?shape sh:property ?propShape .
  ?propShape sh:path ?property .
  FILTER(?property = era:yourLinkingProperty)
}

Common Positioning Patterns (for InfrastructureElements only)

Linear Extent (NetLinearReference)

Used for: Track, Bridge, SpeedSection

?netLinearRef a era:NetLinearReference ;
              era:startOfNetLinearReference ?startRef ;
              era:endOfNetLinearReference ?endRef .

?startRef a era:LinearReference ;
          era:atNetElement ?netElement ;
          era:atPosition ?startPos .

?endRef a era:LinearReference ;
        era:atNetElement ?netElement ;
        era:atPosition ?endPos .

Point Position (NetPointReference)

Used for: Signal, Switch, LevelCrossing, Tunnel endpoints

?netPointRef a era:NetPointReference ;
             era:at era:NetPoint ;
             era:atPosition ?position .

?position a era:LinearReference ;
          era:atNetElement ?netElement ;
          era:atPosition ?intrinsicCoord .

SKOS Concept Mapping

Map railML enumerations to ERA SKOS concepts:

# Define mapping (outside WHERE)
BIND (IF(?railmlValue = "option1",
         IRI("http://data.europa.eu/949/concepts/category/10"),
         IF(?railmlValue = "option2",
            IRI("http://data.europa.eu/949/concepts/category/20"),
            IRI("http://data.europa.eu/949/concepts/category/99")
         )
     ) AS ?eraConcept)

Workshop Simplifications

• Infrastructure Manager: Hardcode to <http://data.europa.eu/949/organisations/0076_IM>
• Country: Use country:NOR
• Dummy Values: Use conservative/safe defaults for required properties without railML source
• Micro-topology: Filter with FILTER NOT EXISTS { ?element fx:topology ?topology }

Common Patterns by Element Type

Infrastructure Elements (subclass of era:InfrastructureElement)

These classes have era:netReference property and use positioning patterns:

• Linear Infrastructure: NetLinearReference with start/end LinearReference
  • Examples: Track, Bridge, SpeedSection
• Point Infrastructure: NetPointReference with single LinearReference
  • Examples: Signal, Switch, LevelCrossing
• Dual-Point Infrastructure: Two separate NetPointReference instances
  • Example: Tunnel (start and end points)
• Aggregate Infrastructure: Property references to contained elements
  • Example: SectionOfLine (hasPart links to Tracks)

Functional Resources (NOT subclass of era:InfrastructureElement)

These classes do NOT have era:netReference and are referenced FROM infrastructure elements:

• ContactLineSystem: Referenced via era:contactLineSystem from Track
• TrainDetectionSystem: Referenced via era:trainDetection from Track
• LoadingGaugeProfile: Referenced via era:gaugingProfile from Track
• TrackGaugeProfile: Referenced via era:wheelSetGauge from Track

Implementation: Link from Track via shared netElements (see functional resource linking pattern above)

Key Considerations

1. Filter Deprecated: Always exclude deprecated properties/classes with FILTER NOT EXISTS { ?x owl:deprecated "true"^^xsd:boolean }
2. Class Hierarchy First: Always check if class is subclass of InfrastructureElement before using positioning patterns
3. SHACL Compliance: Check required properties with era-shacl-analysis skill
4. URI Uniqueness: Use railML xyz:id attributes for ERA URI minting
5. Datatype Casting: Explicit xsd: types for literals
6. Optional Properties: Use OPTIONAL blocks for non-required railML attributes
7. Label: Always include rdfs:label for human readability

Validation

After creating SPARQL file:

1. Check syntax with Jena ARQ or SPARQL.anything
2. Verify SHACL required properties are included
3. Review against similar existing files in project
4. Test against source data if available