Add geojson_to_poly.py

geojson_to_poly.py

@@ -0,0 +1,58 @@
+import json
+import sys
+import os
+
+def write_polygon(f, coords):
+    """Write a single polygon ring to the poly file."""
+    # Close polygon if not already closed
+    if coords[0] != coords[-1]:
+        coords.append(coords[0])
+    for lon, lat in coords:
+        f.write(f"  {lon} {lat}\n")
+    f.write("END\n")
+
+def geojson_to_poly(geojson_file):
+    base_name = os.path.splitext(os.path.basename(geojson_file))[0]
+    poly_file = f"{base_name}.poly"
+
+    with open(geojson_file, 'r', encoding='utf-8') as f:
+        data = json.load(f)
+
+    with open(poly_file, 'w', encoding='utf-8') as f:
+        f.write(f"{base_name}\n")
+        feature_index = 1
+
+        for feature in data["features"]:
+            geom_type = feature["geometry"]["type"]
+            coords = feature["geometry"]["coordinates"]
+
+            if geom_type == "Polygon":
+                # Handle flat array: [ [lon, lat], ... ]
+                if isinstance(coords[0][0], float):
+                    coords = [coords]
+                for ring in coords:
+                    f.write(f"{feature_index}\n")
+                    write_polygon(f, ring)
+                    feature_index += 1
+
+            elif geom_type == "MultiPolygon":
+                for poly in coords:
+                    # Each poly is [ [ [lon, lat], ... ] ]
+                    ring = poly[0]  # use outer ring only
+                    f.write(f"{feature_index}\n")
+                    write_polygon(f, ring)
+                    feature_index += 1
+            else:
+                print(f"Skipping unsupported geometry type: {geom_type}")
+
+        f.write("END\n")
+
+    print(f"Created .poly file: {poly_file}")
+
+if __name__ == "__main__":
+    if len(sys.argv) < 2:
+        print("Usage: python geojson_to_poly.py <geojson_file>")
+        sys.exit(1)
+
+    geojson_file = sys.argv[1]
+    geojson_to_poly(geojson_file)