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# /// script
# requires-python = ">=3.12"
# dependencies = [
# "osmium",
# "shapely",
# "requests",
# "tqdm",
# ]
# ///
import json
import logging
import sys
from argparse import ArgumentParser
from pathlib import Path
import osmium
import osmium.geom
import requests
from shapely.wkb import loads as wkb_loads
from tqdm import tqdm
GEOFABRIK_URL = "https://download.geofabrik.de/europe/spain/galicia-latest.osm.pbf"
DEFAULT_PBF = "galicia-latest.osm.pbf"
DEFAULT_OUTPUT = "parroquias.geojson"
_wkb_factory = osmium.geom.WKBFactory()
class _AdminBoundaryHandler(osmium.SimpleHandler):
"""Collects administrative boundary areas at the requested admin levels."""
def __init__(self, admin_levels: set[str]) -> None:
super().__init__()
self.admin_levels = admin_levels
self.features: list[dict] = []
self._geom_errors = 0
def area(self, a: osmium.osm.Area) -> None: # type: ignore[name-defined]
tags = a.tags
if tags.get("boundary") != "administrative":
return
level = tags.get("admin_level")
if level not in self.admin_levels:
return
try:
wkb = _wkb_factory.create_multipolygon(a)
geom = wkb_loads(wkb, hex=True)
except Exception:
self._geom_errors += 1
return
ref_ine = tags.get("ref:ine", "")
self.features.append(
{
"type": "Feature",
"geometry": geom.__geo_interface__,
"properties": {
"osm_type": "way" if a.from_way() else "relation",
"osm_id": a.orig_id(),
"admin_level": int(level),
"name": tags.get("name", ""),
"name_gl": tags.get("name:gl", ""),
# ref:ine full code (e.g. "15017000000" for a municipality,
# "15017030000" for a parish). First 5 chars are always the
# 5-digit INE municipality code (PP+MMM).
"ref_ine": ref_ine,
"ine_muni": tags.get("ine:municipio", ref_ine[:5] if ref_ine else ""),
"wikidata": tags.get("wikidata", ""),
},
}
)
def _download_pbf(url: str, dest: Path) -> None:
"""Stream-download *url* to *dest*, showing a progress bar.
Skips the download silently if *dest* already exists.
"""
if dest.exists():
logging.info("PBF already present at %s — skipping download.", dest)
return
logging.info("Downloading %s …", url)
with requests.get(url, stream=True, timeout=60) as resp:
resp.raise_for_status()
total = int(resp.headers.get("content-length", 0))
with open(dest, "wb") as fh, tqdm(
total=total, unit="B", unit_scale=True, desc=dest.name
) as bar:
for chunk in resp.iter_content(chunk_size=1 << 20):
fh.write(chunk)
bar.update(len(chunk))
logging.info("Download complete: %s (%.1f MB)", dest, dest.stat().st_size / 1e6)
def main() -> None:
parser = ArgumentParser(
description=(
"Extract Galician parish (admin_level=9) and municipality "
"(admin_level=8) boundaries from an OSM PBF file."
)
)
parser.add_argument(
"--pbf",
type=Path,
default=Path(DEFAULT_PBF),
help=f"Path to OSM PBF file. Downloaded from Geofabrik if absent "
f"(default: {DEFAULT_PBF}).",
)
parser.add_argument(
"--output",
type=Path,
default=Path(DEFAULT_OUTPUT),
help=f"Output GeoJSON file (default: {DEFAULT_OUTPUT}).",
)
parser.add_argument(
"--no-download",
action="store_true",
help="Do not attempt to download the PBF; fail if it is missing.",
)
parser.add_argument(
"--debug",
action="store_true",
help="Enable debug logging.",
)
args = parser.parse_args()
logging.basicConfig(
level=logging.DEBUG if args.debug else logging.INFO,
format="%(asctime)s - %(levelname)s - %(message)s",
)
if not args.no_download:
_download_pbf(GEOFABRIK_URL, args.pbf)
if not args.pbf.exists():
logging.error("PBF file not found: %s", args.pbf)
sys.exit(1)
logging.info("Parsing admin boundaries from %s …", args.pbf)
handler = _AdminBoundaryHandler(admin_levels={"8", "9"})
handler.apply_file(str(args.pbf), locations=True, idx="flex_mem")
n = len(handler.features)
logging.info(
"Found %d boundary features (%d geometry errors skipped).",
n,
handler._geom_errors,
)
if n == 0:
logging.warning(
"No boundaries found — check that the PBF covers Galicia and "
"contains boundary=administrative relations at admin_level 8/9."
)
geojson = {
"type": "FeatureCollection",
"features": handler.features,
}
args.output.write_text(
json.dumps(geojson, ensure_ascii=False, indent=None),
encoding="utf-8",
)
logging.info("Saved %d features to %s", n, args.output)
if __name__ == "__main__":
main()
|
