voxcity.utils.zoning
====================

.. py:module:: voxcity.utils.zoning

.. autoapi-nested-parse::

   Lon/lat polygon utilities for VoxCity grids.

   Bridges geographic polygons (closed lon/lat rings, GeoJSON-style) into
   the grid's (i, j) cell frame. Algorithm: project every cell centre to
   lon/lat via GridProjector, then test point-in-polygon with MplPath.



Functions
---------

.. autoapisummary::

   voxcity.utils.zoning.mask_from_lonlat_ring
   voxcity.utils.zoning.polygon_lonlat_to_cells
   voxcity.utils.zoning.points_in_polygon_lonlat


Module Contents
---------------

.. py:function:: mask_from_lonlat_ring(ring: Sequence[Sequence[float]], grid_geom: voxcity.utils.projector.GridGeom) -> numpy.ndarray

   Rasterize a closed lon/lat ring to a (nx, ny) boolean mask.

   A cell is True iff its centre lies inside the polygon.


.. py:function:: polygon_lonlat_to_cells(ring: Sequence[Sequence[float]], grid_geom: voxcity.utils.projector.GridGeom) -> List[Tuple[int, int]]

   Rasterize a lon/lat ring to a list of (i, j) cell indices.

   Equivalent to ``np.argwhere(mask_from_lonlat_ring(...))`` returned as
   a list of Python tuples. Provided for parity with the helper that has
   historically lived in app/backend/zoning.py; new code should prefer
   ``mask_from_lonlat_ring``.


.. py:function:: points_in_polygon_lonlat(points_lonlat: numpy.ndarray, ring: Sequence[Sequence[float]]) -> numpy.ndarray

   Vectorized point-in-polygon test (boolean array of length N).