Add postcode mapping

pipeline/download/oa_boundaries.py

@@ -0,0 +1,36 @@
+"""Download Output Areas (December 2021) Boundaries EW BGC (V2).
+
+Generalised clipped (20m) boundary polygons for 2021 Census Output Areas
+covering England and Wales.
+
+Source: https://open-geography-portalx-ons.hub.arcgis.com/datasets/ons::output-areas-december-2021-boundaries-ew-bgc-v2
+License: Open Government Licence v3.0
+"""
+
+import argparse
+from pathlib import Path
+
+from pipeline.utils import download
+
+URL = "https://open-geography-portalx-ons.hub.arcgis.com/api/download/v1/items/6beafcfd9b9c4c9993a06b6b199d7e6d/geoPackage?layers=0"
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(
+        description="Download OA 2021 boundary polygons (England & Wales)"
+    )
+    parser.add_argument(
+        "--output",
+        type=Path,
+        required=True,
+        help="Output GeoPackage file path",
+    )
+    args = parser.parse_args()
+
+    args.output.parent.mkdir(parents=True, exist_ok=True)
+    download(URL, args.output, timeout=600)
+    print(f"Saved to {args.output}")
+
+
+if __name__ == "__main__":
+    main()