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."