perfect-postcode/pipeline/download/arcgis.py
2026-01-31 13:07:09 +00:00

72 lines
2.1 KiB
Python

import argparse
import tempfile
import zipfile
import httpx
import polars as pl
from pathlib import Path
from tqdm import tqdm
URL = "https://www.arcgis.com/sharing/rest/content/items/077631e063eb4e1ab43575d01381ec33/data"
def download_with_progress(url: str, output_path: Path) -> None:
with httpx.stream(
"GET",
url,
follow_redirects=True,
timeout=httpx.Timeout(30.0, read=None),
) as response:
response.raise_for_status() # pyright: ignore[reportUnusedCallResult]
total = int(response.headers.get("content-length", 0))
with (
open(output_path, "wb") as f,
tqdm(
total=total,
unit="B",
unit_scale=True,
unit_divisor=1024,
desc="Downloading",
) as pbar,
):
for chunk in response.iter_bytes(chunk_size=8192):
f.write(chunk)
pbar.update(len(chunk))
return
def extract_zip(zip_path: Path, extract_path: Path) -> None:
extract_path.mkdir(exist_ok=True)
with zipfile.ZipFile(zip_path, "r") as zf:
zf.extractall(extract_path)
def convert_to_parquet(data_path: Path, parquet_path: Path) -> None:
df = pl.scan_csv(data_path / "Data/NSPL_MAY_2025_UK.csv", try_parse_dates=True)
print(f"Columns: {df.collect_schema().names()}")
parquet_path.parent.mkdir(parents=True, exist_ok=True)
df.sink_parquet(parquet_path, compression="zstd")
print(f"Saved to {parquet_path}")
def main() -> None:
parser = argparse.ArgumentParser(
description="Download and convert ArcGIS postcode data"
)
parser.add_argument(
"--output", type=Path, required=True, help="Output parquet file path"
)
args = parser.parse_args()
with tempfile.TemporaryDirectory() as cache_dir:
download_path = Path(cache_dir) / "arcgis_data.zip"
extract_path = Path(cache_dir) / "arcgis_extracted"
download_with_progress(URL, download_path)
extract_zip(download_path, extract_path)
convert_to_parquet(extract_path, args.output)
if __name__ == "__main__":
main()