dc-l1-tokyo-ring-orientation

Rerun

import geopandas as gpd

def inspect_geometry(gdf):
    for idx, row in gdf.iterrows():
        geom = row.geometry
        if geom.is_empty:
            print(f"Index {idx}: Empty geometry")
        if not geom.is_valid:
            print(f"Index {idx}: Invalid geometry. Reason: {geom.reason if hasattr(geom, 'reason') else 'unknown'}")
            # Check for common issues like self-intersection
            # In GeoPandas/Shapely, we can check is_valid
        
        # Check ring orientation for Polygons
        if geom.geom_type == 'Polygon':
            # The exterior ring should be counter-clockwise in some conventions, 
            # but GeoJSON/RFC 7946 specifies exterior ring is CCW and holes are CW.
            # However, "holes appear filled and exteriors render as empty space" 
            # strongly suggests the winding order is reversed.
            pass

inspect_geometry(gpd.read_file('tokyo_buildings_legacy.geojson'))

import geopandas as gpd

def inspect_geometry(gdf):
    invalid_count = 0
    for idx, row in gdf.iterrows():
        geom = row.geometry
        if not geom.is_valid:
            invalid_count += 1
            print(f"Index {idx}: Invalid geometry. Reason: {geom.reason}")
    print(f"Total invalid geometries: {invalid_count}")

gdf = gpd.read_file('tokyo_buildings_legacy.geojson')
inspect_geometry(gdf)
print("CRS:", gdf.crs)
print("First geometry:", gdf.geometry.iloc[0])

import geopandas as gpd
import json

def check_winding(gdf):
    for idx, row in gdf.iterrows():
        geom = row.geometry
        if geom.geom_type == 'Polygon':
            ext_coords = list(geom.exterior.coords)
            # Check if exterior is CCW (standard for GeoJSON)
            # In Shapely, is_ccw returns True if the ring is counter-clockwise.
            # Note: GeoJSON RFC 7946 says exterior should be CCW.
            if not geom.exterior.is_ccw:
                print(f"Index {idx}: Exterior is CW")
            
            # Check holes
            for i, interior in enumerate(geom.interiors):
                if interior.is_ccw:
                    print(f"Index {idx}: Hole {i} is CCW (should be CW)")
                else:
                    print(f"Index {idx}: Hole {i} is CW")

gdf = gpd.read_file('tokyo_buildings_legacy.geojson')
check_winding(gdf)

import geopandas as gpd
from shapely.geometry import Polygon, MultiPolygon
from shapely.ops import orient

def fix_polygon_winding(geom):
    if geom.is_empty:
        return geom
    
    if geom.geom_type == 'Polygon':
        # orient(polygon, sign=1.0) ensures exterior is CCW and holes are CW
        # sign=1.0 for CCW exterior
        return orient(geom, sign=1.0)
    
    elif geom.geom_type == 'MultiPolygon':
        fixed_parts = [orient(part, sign=1.0) for part in geom.geoms]
        return MultiPolygon(fixed_parts)
    
    return geom

def main():
    input_file = 'tokyo_buildings_legacy.geojson'
    output_file = 'tokyo_buildings_fixed.geojson'
    
    gdf = gpd.read_file(input_file)
    
    print(f"Processing {len(gdf)} features...")
    
    # Apply the orientation fix
    gdf['geometry'] = gdf['geometry'].apply(fix_polygon_winding)
    
    # Also ensure geometries are valid (just in case)
    gdf['geometry'] = gdf['geometry'].buffer(0)
    
    # Save to GeoJSON
    # Note: GeoPandas uses pyogrio or fiona. 
    # To ensure RFC 7946 compliance (winding order), we should check if the driver respects it.
    # Standard GeoJSON writing in most libraries usually respects the geometry's orientation.
    gdf.to_file(output_file, driver='GeoJSON')
    print(f"Successfully saved fixed geometries to {output_file}")

if __name__ == "__main__":
    main()

import geopandas as gpd
from shapely.geometry import Polygon, MultiPolygon
from shapely.ops import orient

def check_winding(gdf):
    errors = 0
    for idx, row in gdf.iterrows():
        geom = row.geometry
        if geom.geom_type == 'Polygon':
            if not geom.exterior.is_ccw:
                errors += 1
            for interior in geom.interiors:
                if interior.is_ccw:
                    errors += 1
        elif geom.geom_type == 'MultiPolygon':
            for part in geom.geoms:
                if not part.exterior.is_ccw:
                    errors += 1
                for interior in part.interiors:
                    if interior.is_ccw:
                        errors += 1
    return errors

print("Checking original file...")
gdf_old = gpd.read_file('tokyo_buildings_legacy.geojson')
err_old = check_winding(gdf_old)
print(f"Original errors (wrong winding): {err_old}")

print("Checking fixed file...")
gdf_new = gpd.read_file('tokyo_buildings_fixed.geojson')
err_new = check_winding(gdf_new)
print(f"Fixed errors (wrong winding): {err_new}")

# Check if geometries are valid
print("Checking validity...")
valid_old = not gdf_old.is_valid.all()
valid_new = not gdf_new.is_valid.all()
print(f"Original has invalid: {valid_old}")
print(f"Fixed has invalid: {valid_new}")

# Check if attributes are preserved
print("Checking attributes...")
# feature_id was mentioned as a join key
if 'feature_id' in gdf_old.columns:
    match = gdf_old['feature_id'].equals(gdf_new['feature_id'])
    print(f"feature_id preserved: {match}")
else:
    print(f"feature_id column NOT found. Available columns: {gdf_old.columns.tolist()}")

# Check feature count
print(f"Feature count match: {len(gdf_old) == len(gdf_new)}")

import geopandas as gpd
from shapely.geometry import Polygon, MultiPolygon
from shapely.ops import orient

def fix_polygon_winding(geom):
    if geom.is_empty:
        return geom
    
    if geom.geom_type == 'Polygon':
        # orient(polygon, sign=1.0) ensures exterior is CCW and holes are CW
        return orient(geom, sign=1.0)
    
    elif geom.geom_type == 'MultiPolygon':
        fixed_parts = [orient(part, sign=1.0) for part in geom.geoms]
        return MultiPolygon(fixed_parts)
    
    return geom

def main():
    input_file = 'tokyo_buildings_legacy.geojson'
    output_file = 'tokyo_buildings_fixed.geojson'
    
    gdf = gpd.read_file(input_file)
    
    print(f"Processing {len(gdf)} features...")
    
    # Apply the orientation fix
    gdf['geometry'] = gdf['geometry'].apply(fix_polygon_winding)
    
    # To ensure we are actually fixing the file for web-viewers, 
    # we must ensure the GeoJSON export process preserves the orientation.
    # Some engines might re-orient them. 
    # However, orient(geom, sign=1.0) is the standard way to set it.
    
    # Let's also double check if the driver is the issue.
    # We'll use the standard GeoJSON driver.
    gdf.to_file(output_file, driver='GeoJSON')
    print(f"Successfully saved fixed geometries to {output_file}")

if __name__ == "__main__":
    main()