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RoadSegment

Entity Description​

The RoadSegment entity represents a specific section of a road. It is used to map traffic data and environmental impacts to physical infrastructure.

JSON Structure​

A typical RoadSegment entity in NGSI-LD format looks like this:

{
  "id": "urn:ngsi-ld:RoadSegment:Segment-A",
  "type": "RoadSegment",
  "name": {
    "type": "Property",
    "value": "Main Street - Block 1"
  },
  "roadClass": {
    "type": "Property",
    "value": "MAJOR_CITY_ROAD"
  },
  "allowedVehicleType": {
    "type": "Property",
    "value": ["car", "bus", "bicycle"]
  },
  "maximumAllowedSpeed": {
    "type": "Property",
    "value": 50
  },
  "totalLaneNumber": {
    "type": "Property",
    "value": 2
  },
  "location": {
    "type": "GeoProperty",
    "value": {
      "type": "LineString",
      "coordinates": [
        [-3.703, 40.416],
        [-3.704, 40.417]
      ]
    }
  }
}

Key Fields​

  • id: Unique identifier for the road segment.
  • type: Entity type, must be RoadSegment.
  • name: Human-readable name of the segment.
  • roadClass: Classification of the road (e.g., motorway, primary, residential).
  • allowedVehicleType: List of vehicle types allowed on this segment.
  • maximumAllowedSpeed: Speed limit for the segment.
  • location: GeoJSON LineString representing the path of the road segment.

Smart Data Models​

This data model adheres to the Smart Data Models standard for Transportation. It is compatible with DATEX II and OpenStreetMap standards.

Application​

Data Validation​

  • Geometry: The location is typically a LineString, validated to ensure it contains valid coordinates.
  • Enums: roadClass and allowedVehicleType are validated against standard lists to ensure consistency.

Documentation​

  • Map Rendering: Frontend applications use the location field to draw the road network on maps.
  • Routing: Navigation algorithms use maximumAllowedSpeed and allowedVehicleType to calculate optimal routes.

Uniqueness & Linked Data​

  • Uniqueness: roadClass is mapped to fiware:roadClass, standardizing road types across the platform.
  • Linked Data: RoadSegment acts as a hub. TrafficEnvironmentImpact and TrafficFlowObserved entities link to it via refRoadSegment, allowing data aggregation by location.

Intelligent Query Support​

  • Spatial Queries: "Find all road segments within a specific polygon."
  • Attribute Queries: "Identify all MAJOR_CITY_ROAD segments where the speed limit is greater than 50 km/h."
  • Impact Correlation: "Show road segments with high traffic density but low air quality."