{
  "type": "FeatureCollection",
  "name": "Synthetic example only — not real stations",
  "features": [
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [
          120.0,
          30.0
        ]
      },
      "properties": {
        "id": "DEMO-1",
        "data_type": "synthetic",
        "description": "虚构节点，仅用于字段结构演示"
      }
    },
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [
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        ]
      },
      "properties": {
        "id": "DEMO-2",
        "data_type": "synthetic",
        "description": "虚构节点，仅用于字段结构演示"
      }
    },
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [
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        ]
      },
      "properties": {
        "id": "DEMO-3",
        "data_type": "synthetic",
        "description": "虚构节点，仅用于字段结构演示"
      }
    }
  ]
}