urbanity.geom

Geometric utility functions for working with urban spatial data. These are low-level helpers used internally and can also be called directly.

from urbanity import geom

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Coordinate & CRS Utilities

get_utm_crs

geom.get_utm_crs(gdf) -> str

Returns the appropriate UTM CRS EPSG code for a GeoDataFrame based on its centroid location. Useful for projecting to a metric CRS before distance calculations.

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project_to_utm

geom.project_to_utm(gdf) -> GeoDataFrame

Projects a GeoDataFrame from geographic coordinates (WGS84) into the best-fit UTM zone.

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Spatial Operations

buffer_geometry

geom.buffer_geometry(gdf, distance: float, cap_style: int = 1) -> GeoDataFrame

Buffers all geometries in a GeoDataFrame by distance metres (after projecting to UTM).

Parameter	Type	Description
gdf	GeoDataFrame	Input geometries.
distance	float	Buffer radius in metres.
cap_style	int	Shapely cap style: 1 = round, 2 = flat, 3 = square.

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compute_voronoi

geom.compute_voronoi(points_gdf) -> GeoDataFrame

Computes Voronoi polygons for a set of point geometries, clipped to the convex hull of the input.

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snap_points_to_network

geom.snap_points_to_network(points_gdf, edges_gdf, threshold: float = 50.0) -> GeoDataFrame

Snaps each point to the nearest edge in the network within threshold metres. Returns the points GeoDataFrame with added nearest_edge_id and distance_to_edge columns.

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Geometry Helpers

get_polygon_bounds

geom.get_polygon_bounds(gdf) -> tuple

Returns (minx, miny, maxx, maxy) bounding box for a GeoDataFrame in WGS84.

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polygon_to_bbox

geom.polygon_to_bbox(polygon) -> dict

Converts a Shapely polygon to an {"north", "south", "east", "west"} bounding-box dict compatible with OSM query APIs.

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split_polygon_grid

geom.split_polygon_grid(polygon, cell_size: float = 1000.0) -> list

Splits a large polygon into a regular grid of smaller cells (cell size in metres). Useful for tiling large-area data downloads.