added export scripts for ortho and buildings

export_buildings.py

@@ -0,0 +1,102 @@
+#!/usr/bin/env python3
+"""Clip CityGML LoD2 buildings per terrain tile and export as OBJ meshes.
+
+Inputs
+- raw_3dgeb_lod2/LoD2_<utm>_<easting>_<northing>.gml : source building tiles
+- export_unity/tile_index.csv : manifest produced by export_heightmaps.py
+
+Outputs
+- export_unity/buildings_obj/<tile_id>.obj : clipped building geometries per tile
+"""
+from __future__ import annotations
+
+import csv
+import os
+from pathlib import Path
+
+from osgeo import gdal
+
+RAW_GML_DIR = Path("raw_3dgeb_lod2")
+TILE_INDEX = Path("export_unity/tile_index.csv")
+OUT_DIR = Path("export_unity/buildings_obj")
+
+OUTPUT_FORMAT = "OBJ"  # glTF driver is not always available; OBJ is widely supported.
+
+gdal.UseExceptions()
+OUT_DIR.mkdir(parents=True, exist_ok=True)
+
+
+def gml_path_for_tile(tile_id: str) -> Path:
+    """Map a DGM tile id (dgm1_utm_easting_northing) to the corresponding CityGML file."""
+    parts = tile_id.split("_")
+    if len(parts) != 4 or parts[0] != "dgm1":
+        raise ValueError(f"Unexpected tile_id format: {tile_id}")
+    utm_zone, easting, northing = parts[1:]
+    return RAW_GML_DIR / f"LoD2_{utm_zone}_{easting}_{northing}.gml"
+
+
+def open_dataset(path: str, purpose: str):
+    """Open a dataset and fail fast with context."""
+    try:
+        ds = gdal.OpenEx(path)
+    except RuntimeError as exc:
+        raise SystemExit(f"{purpose}: {exc}") from exc
+    if ds is None:
+        raise SystemExit(f"{purpose}: GDAL returned None for {path}")
+    return ds
+
+
+def main() -> None:
+    if not TILE_INDEX.exists():
+        raise SystemExit(f"Tile index missing: {TILE_INDEX}. Run export_heightmaps.py first.")
+
+    written = 0
+    skipped = 0
+
+    with TILE_INDEX.open(newline="", encoding="utf-8") as f:
+        reader = csv.DictReader(f)
+        for row in reader:
+            try:
+                tile_id = row["tile_id"]
+                xmin = float(row["xmin"])
+                ymin = float(row["ymin"])
+                xmax = float(row["xmax"])
+                ymax = float(row["ymax"])
+            except (KeyError, ValueError) as exc:
+                print(f"Skipping malformed row {row}: {exc}")
+                skipped += 1
+                continue
+
+            gml_path = gml_path_for_tile(tile_id)
+            if not gml_path.exists():
+                print(f"Missing CityGML for {tile_id}: {gml_path}")
+                skipped += 1
+                continue
+
+            out_path = OUT_DIR / f"{tile_id}.obj"
+
+            src_ds = open_dataset(str(gml_path), f"Could not open {gml_path}")
+
+            opts = gdal.VectorTranslateOptions(
+                format=OUTPUT_FORMAT,
+                spatFilter=(xmin, ymin, xmax, ymax),
+                layerName="Building",  # matches GML layer name
+            )
+
+            try:
+                gdal.VectorTranslate(destNameOrDestDS=str(out_path), srcDS=src_ds, options=opts)
+            except RuntimeError as exc:
+                print(f"VectorTranslate failed for {tile_id}: {exc}")
+                skipped += 1
+                continue
+
+            written += 1
+            print(f"Wrote {out_path}")
+
+    print(f"Summary: wrote {written} building tiles; skipped {skipped}.")
+    if skipped:
+        raise SystemExit(1)
+
+
+if __name__ == "__main__":
+    main()