download_files_from_LGL_BW.py

# -*- coding: utf-8 -*-
"""
LoD2 CityGML tiles are available for whole Baden-Württemberg, from LGL.

https://opengeodata.lgl-bw.de/#/(sidenav:product/12)

This script downloads the requires tiles for given regions
(as WKT strings, in *polygons* variable), and extracts the region.

Required:
* Python
* pyproj project (https://pypi.org/project/pyproj/)
* SimStadt installed on the Desktop (for RegionChooser)

Eric Duminil, 2024
"""
from pathlib import Path
from math import floor
import subprocess
import re
import urllib.request
import time
import zipfile

from pyproj import CRS
from pyproj import Transformer

###### User input ##########
POLYGONS = {
    "StuttgartCenter": "POLYGON((9.175287 48.780916, 9.185501 48.777522, 9.181467 48.773704, 9.174429 48.768472, 9.168807 48.773902, 9.175287 48.780916))",
    # "AnotherRegion": "Another WKT Polygon...",
}
# Should RegionChooser extract the regions from multiple CityGMLs?
EXTRACT_REGIONS = True
############################


CITYGML_SERVER = "https://opengeodata.lgl-bw.de/data/lod2"
RASTER = 2  # [km]
BUNDESLAND = 'bw'
WGS84 = CRS.from_epsg(4326)

LOCAL_CRS = CRS.from_epsg(32632)  # UTM32N, used in BW. https://epsg.io/32632
UTM = 32

SCRIPT_DIR = Path(__file__).parent
WAIT_BETWEEN_DOWNLOADS = 5  # [s] Be nice to LGL Server.

if EXTRACT_REGIONS:
    try:
        SIMSTADT_FOLDER = next(x for x in Path.home().glob('Desktop/SimStadt*_0.*/') if x.is_dir())
        print(f"RegionChooser has been found in {SIMSTADT_FOLDER}")
    except StopIteration:
        exit("No SimStadt installation found!"
             "\nPlease copy a SimStadt installation to the desktop,"
             "\nset EXTRACT_REGIONS to False,"
             "\nor set SIMSTADT_FOLDER manually: SIMSTADT_FOLDER = Path('/path/to/SimStadt')"
             )
    GML_GLOB = "LoD2_*/LoD2_*.gml"


def coordinates_to_grid(longitude: float, latitude: float, local_utm: CRS) -> tuple[int, int]:
    """Returns (x, y) of the tile on CITYGML_SERVER containing a given point."""
    transformer = Transformer.from_crs(WGS84, local_utm, always_xy=True)
    x, y = transformer.transform(longitude, latitude)
    x = floor(x / 1000) - 1  # Odd x
    y = floor(y / 1000)  # Even y
    x -= x % RASTER
    y -= y % RASTER
    return (x + 1, y)


def wkt_polygon_to_grid_coords(location_name: str, wkt: str) -> tuple[int, int, int, int]:
    """Returns (x, y) of lower-left and bottom-right tiles, containing a given region."""
    if 'POLYGON' not in wkt:
        raise ValueError(f"wkt for {location_name} should be a WKT POLYGON or MULTIPOLYGON")

    coordinates = re.findall(r'\-?\d+\.\d+', wkt)

    lons = [float(lon) for lon in coordinates[::2]]
    lats = [float(lat) for lat in coordinates[1::2]]

    min_lon, max_lon = min(lons), max(lons)
    min_lat, max_lat = min(lats), max(lats)

    print("%s (%.3f°N %.3f°E -> %.3f°N %.3f°E)" % (location_name, max_lat, min_lon, min_lat, max_lon))

    x1, y1 = coordinates_to_grid(min_lon, min_lat, LOCAL_CRS)
    x2, y2 = coordinates_to_grid(max_lon, max_lat, LOCAL_CRS)

    return (x1, x2, y1, y2)


def download_rectangle(output_dir: Path, x1: int, x2: int, y1: int, y2: int) -> None:
    """Downloads every zip of a given region, to output_dir, and extracts CityGML files."""
    for x in range(x1, x2 + 1, RASTER):
        for y in range(y1, y2 + 1, RASTER):
            citygml_zip = f"LoD2_{UTM}_{x}_{y}_{RASTER}_{BUNDESLAND}.zip"
            citygml_url = f"{CITYGML_SERVER}/{citygml_zip}"
            local_zip = output_dir / citygml_zip  # .replace('.zip', '.gml')
            if local_zip.exists():
                print(f"  {local_zip.name} already in {output_dir.name}/")
            else:
                print(f"  Download {citygml_zip} to {output_dir.name}/ ", end='')
                try:
                    urllib.request.urlretrieve(citygml_url, local_zip)
                except urllib.error.HTTPError as e:
                    print(f"❌ {e}")
                    continue
                finally:
                    time.sleep(WAIT_BETWEEN_DOWNLOADS)
                print("✅")

                print(f"    Extract {citygml_zip} to {output_dir.name}/ ", end='')
                print("✅")
                print("")
                with zipfile.ZipFile(local_zip, "r") as zip_ref:
                    zip_ref.extractall(output_dir)


def extract_region(output_dir: Path, location_name: str, wkt: str) -> None:
    """Uses RegionChooser to extract a given region from all the CityGML files found in subfolder."""
    output_file = output_dir / (location_name + '.gml')
    if output_file.exists():
        print(f"  {output_file} already exists. Not extracting.")
        return
    region_chooser_libs = Path(SIMSTADT_FOLDER).expanduser() / 'lib/*'
    gml_inputs = list(output_dir.glob(GML_GLOB))
    if len(gml_inputs) == 0:
        print("Error: No CityGML found. At least part of the region should be in Baden-Württemberg!")
        return
    print(f"  Extracting {output_file}.")
    result = subprocess.run(['java', '-classpath', f'{region_chooser_libs}',
                             'eu.simstadt.regionchooser.RegionChooserCLI',
                             '--input', ','.join(str(gml) for gml in gml_inputs),
                             '--output', str(output_file),
                             '--wkt', '-',
                             ],
                            input=wkt,
                            text=True,
                            capture_output=True,
                            check=True
                            )
    if (result.stderr):
        print(result.stderr)
    print("  DONE!")


def main(polygons: dict[str, str]) -> None:
    """Downloads ZIP files, extracts CityGML files, and selects desired region."""
    for location_name, wkt in polygons.items():
        output_dir = SCRIPT_DIR / (location_name + '.proj')
        output_dir.mkdir(parents=True, exist_ok=True)
        x1, x2, y1, y2 = wkt_polygon_to_grid_coords(location_name, wkt)
        download_rectangle(output_dir, x1, x2, y1, y2)
        if EXTRACT_REGIONS:
            extract_region(output_dir, location_name, wkt)
        print()


if __name__ == '__main__':
    main(POLYGONS)