Initial import

src/vector_tile_generator.py

@@ -0,0 +1,136 @@
+import os
+from collections import defaultdict
+from pathlib import Path
+import json
+
+try:
+    import mapbox_vector_tile
+except ModuleNotFoundError:  # pragma: no cover - dependency guard for runtime environments
+    mapbox_vector_tile = None
+
+try:
+    import mercantile
+except ModuleNotFoundError:  # pragma: no cover - dependency guard for runtime environments
+    mercantile = None
+
+PROJECT_ROOT = Path(__file__).resolve().parent.parent
+GRID_DIR = PROJECT_ROOT / "data" / "grid"
+OUTPUT_DIR = Path("/home/wwwroot/weather")
+
+DEFAULT_ZOOMS = [2, 4, 6, 8, 10, 12]
+
+
+def get_zoom_levels():
+    raw_value = os.environ.get("WEATHER_TILE_ZOOMS", "")
+    if not raw_value.strip():
+        return DEFAULT_ZOOMS
+
+    zooms = []
+    for chunk in raw_value.split(","):
+        chunk = chunk.strip()
+        if not chunk:
+            continue
+        zoom = int(chunk)
+        if zoom < 0:
+            raise ValueError(f"Invalid zoom level: {zoom}")
+        zooms.append(zoom)
+
+    if not zooms:
+        raise ValueError("WEATHER_TILE_ZOOMS did not contain any usable zoom levels")
+
+    return sorted(set(zooms))
+
+
+def load_grid(path):
+    with path.open(encoding="utf-8") as file_handle:
+        data = json.load(file_handle)
+    return data["time"], data["grid"]
+
+
+def get_grid_field(grid, field_name, latitudes, longitudes):
+    values = grid.get(field_name)
+    if values is not None:
+        return values
+
+    return [[0.0 for _ in longitudes] for _ in latitudes]
+
+
+def grid_to_features(grid):
+    latitudes = grid["lat"]
+    longitudes = grid["lon"]
+    wind_speed = grid["wind_speed"]
+    wind_dir = grid["wind_dir"]
+    rain = grid["rain"]
+    temp = grid["temp"]
+    pressure = grid["pressure"]
+    wave_h = get_grid_field(grid, "wave_h", latitudes, longitudes)
+    wave_dir = get_grid_field(grid, "wave_dir", latitudes, longitudes)
+    wave_period = get_grid_field(grid, "wave_period", latitudes, longitudes)
+
+    features = []
+    for lat_index, latitude in enumerate(latitudes):
+        for lon_index, longitude in enumerate(longitudes):
+            features.append(
+                {
+                    "geometry": {"type": "Point", "coordinates": [longitude, latitude]},
+                    "properties": {
+                        "ws": wind_speed[lat_index][lon_index],
+                        "wd": wind_dir[lat_index][lon_index],
+                        "r": rain[lat_index][lon_index],
+                        "t": temp[lat_index][lon_index],
+                        "p": pressure[lat_index][lon_index],
+                        "wh": wave_h[lat_index][lon_index],
+                        "wdir": wave_dir[lat_index][lon_index],
+                        "wp": wave_period[lat_index][lon_index],
+                    },
+                }
+            )
+    return features
+
+
+def bucket_features_by_tile(features, zoom):
+    buckets = defaultdict(list)
+    for feature in features:
+        longitude, latitude = feature["geometry"]["coordinates"]
+        tile = mercantile.tile(longitude, latitude, zoom)
+        buckets[(tile.x, tile.y)].append(feature)
+    return buckets
+
+
+def write_tile(tile_time, zoom, tile_x, tile_y, features):
+    bounds = mercantile.bounds(mercantile.Tile(x=tile_x, y=tile_y, z=zoom))
+    tile_dir = OUTPUT_DIR / tile_time / str(zoom) / str(tile_x)
+    tile_dir.mkdir(parents=True, exist_ok=True)
+    tile_path = tile_dir / f"{tile_y}.pbf"
+
+    layer = {"name": "weather", "features": features}
+    tile_data = mapbox_vector_tile.encode(
+        layer,
+        default_options={
+            "quantize_bounds": (bounds.west, bounds.south, bounds.east, bounds.north),
+        },
+    )
+    tile_path.write_bytes(tile_data)
+    print("tile", tile_time, zoom, tile_x, tile_y)
+
+
+def generate_tiles(tile_time, features):
+    for zoom in get_zoom_levels():
+        buckets = bucket_features_by_tile(features, zoom)
+        for (tile_x, tile_y), tile_features in buckets.items():
+            write_tile(tile_time, zoom, tile_x, tile_y, tile_features)
+
+
+def main():
+    if mapbox_vector_tile is None or mercantile is None:
+        raise RuntimeError("mapbox-vector-tile and mercantile are required to generate vector tiles")
+
+    for path in sorted(GRID_DIR.glob("*.json")):
+        print("processing", path.name)
+        tile_time, grid = load_grid(path)
+        features = grid_to_features(grid)
+        generate_tiles(tile_time, features)
+
+
+if __name__ == "__main__":
+    main()