NGSI-LD to RDF Agent

The NGSI-LD to RDF Agent converts NGSI-LD entities to pure RDF/Turtle format.

📋 Overview

Property	Value
Module	src.agents.rdf_linked_data.ngsi_ld_to_rdf_agent
Class	NGSILDToRDFAgent
Author	UIP Team
Version	1.0.0

🎯 Purpose

• Convert NGSI-LD to RDF with proper ontology mappings
• Preserve semantic meaning during conversion
• Apply domain ontologies (SOSA, SSN, GeoSPARQL)
• Generate clean Turtle output

🚀 Usage

Convert Single Entity

from src.agents.rdf_linked_data.ngsi_ld_to_rdf_agent import NGSILDToRDFAgent

agent = NGSILDToRDFAgent()

ngsi_entity = {
    "id": "urn:ngsi-ld:TrafficCamera:CAM_001",
    "type": "TrafficCamera",
    "location": {
        "type": "GeoProperty",
        "value": {"type": "Point", "coordinates": [106.6297, 10.8231]}
    },
    "vehicleCount": {
        "type": "Property",
        "value": 42,
        "observedAt": "2025-11-29T10:30:00Z"
    }
}

# Convert to RDF
rdf_graph = agent.convert(ngsi_entity)

# Serialize to Turtle
turtle = rdf_graph.serialize(format="turtle")

Batch Conversion

# Convert multiple entities
entities = [entity1, entity2, entity3]
combined_graph = agent.convert_batch(entities)

With Ontology Mappings

# Convert with SOSA/SSN ontology
rdf_graph = agent.convert(
    entity=sensor_entity,
    ontology="sosa",
    include_metadata=True
)

⚙️ Configuration

# config/ngsi_ld_mappings.yaml
ngsi_ld_to_rdf:
  enabled: true
  
  # Base URI
  base_uri: "https://uip.city.gov/entities/"
  
  # Ontology mappings
  ontologies:
    sosa:
      prefix: "http://www.w3.org/ns/sosa/"
      mappings:
        TrafficCamera: "sosa:Platform"
        vehicleCount: "sosa:observedProperty"
    geo:
      prefix: "http://www.opengis.net/ont/geosparql#"
      mappings:
        location: "geo:hasGeometry"
  
  # Output settings
  output:
    format: "turtle"
    include_prefixes: true
    pretty_print: true

📊 Mapping Example

NGSI-LD Input

{
  "id": "urn:ngsi-ld:TrafficCamera:CAM_001",
  "type": "TrafficCamera",
  "vehicleCount": {
    "type": "Property",
    "value": 42
  }
}

RDF/Turtle Output

@prefix sosa: <http://www.w3.org/ns/sosa/> .
@prefix uip: <https://uip.city.gov/entities/> .

uip:TrafficCamera_CAM_001 a sosa:Platform ;
    sosa:hosts uip:Sensor_CAM_001 ;
    sosa:madeObservation [
        a sosa:Observation ;
        sosa:observedProperty uip:vehicleCount ;
        sosa:hasSimpleResult 42
    ] .

📖 Related Documentation

• SOSA-SSN Mapper - Sensor ontology
• Triplestore Loader - RDF storage
• Content Negotiation - Format handling

---

See the complete agents reference for all available agents.