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🌀 Buffer Transformation

A buffer in Geographic Information Systems (GIS) is a zone created at a specified distance around a geographic feature such as a point, line, or polygon. Buffers are one of the most widely used spatial analysis tools because they allow you to analyze the proximity and influence of features.

🧭 What is a Buffer?​

  • Point Buffers — circular zones around a location (e.g., cellular towers, wells).
  • Line Buffers — bands around linear features (e.g., roads, rivers) for corridors, pollution analysis, or setback rules.
  • Polygon Buffers — rings around polygons (e.g., parks, industrial zones) to model impact or regulatory zones.

Depending on the data, buffers help answer questions like: “What falls within 500 meters of this road?” or “Which buildings are inside a 1 km zone around the river?”

Buffer Illustration

⚙️ Parameters​

The buffer transformation requires two parameters:

{
  "type": "buffer",
  "params": {
    "distance": <number>,        // how far to buffer
    "units": "meters|kilometers|feet|miles"
  }
}
  • distance — the buffer radius (float).
  • units — measurement unit (meters, kilometers, feet, miles).

📑 Example Usage​

Example Config (GeoJSON input → buffered SHP output)​

{
  "input": { "format": "geojson" },
  "transformations": [
    {
      "type": "buffer",
      "params": { "distance": 250, "units": "meters" }
    }
  ],
  "output": { "format": "shp", "epsg": 4326 }
}

Example API Call​

curl -X POST https://api.geoflip.io/transform \
  -F 'config={
    "input":{"format":"geojson"},
    "transformations":[{"type":"buffer","params":{"distance":250,"units":"meters"}}],
    "output":{"format":"shp","epsg":4326}
  }' \
  -F "input_file=@/path/to/input.geojson;type=application/geo+json"

Response

{ "job_id": "abcd-ef01-2345-6789" }

Poll for status, then download from the returned output_url when the job reaches SUCCESS.

✅ Notes​

  • Buffers work with GeoJSON, SHP, and DXF inputs.
  • Ensure input.epsg is set for DXF files (since CRS is not stored in DXF).
  • Output can be requested in geojson, shp, or dxf.
  • Multiple transformations can be chained, e.g., buffer → union.

➡️ Next Steps​