urbanflow.utils.courtyard_utils

courtyard_utils.py

Utilities for loading and generating courtyard files

Functions

add_auto_courtyards(grid, *[, empty_code, ...])

Automatically label enclosed empty cells as courtyards.
urbanflow.utils.courtyard_utils.add_auto_courtyards(grid, *, empty_code=0, courtyard_code=4, structure=None)

Automatically label enclosed empty cells as courtyards.

Any cell in grid with value empty_code that is not 8-connected to the raster border is reclassified as courtyard_code. The operation is performed in-place using fast morphological propagation.

Parameters:

  • grid (ndarray of int) – 2D raster array representing land-use classes or categories. Modified in-place.

  • empty_code (int, optional) – Value used to indicate empty cells, by default 0.

  • courtyard_code (int, optional) – Value used to indicate courtyard cells, by default 4.

  • structure (ndarray of bool, optional) – Structuring element defining connectivity for propagation. Defaults to a 3×3 matrix of ones (8-connectivity).

Returns:

grid – Same array as input, with enclosed empty cells relabeled as courtyards.

Return type:

ndarray of int

Notes

  • Connectivity is determined using scipy.ndimage.binary_propagation.

  • Empty cells connected to the border remain unchanged.

  • Empty cells fully enclosed by structures are converted into courtyards.

Examples

>>> import numpy as np
>>> from urbanflow.utils.courtyard_utils import add_auto_courtyards
>>> grid = np.array([
...     [0,0,0,0],
...     [0,2,2,0],
...     [0,2,0,0],
...     [0,0,0,0],
... ], dtype=np.uint8)
>>> add_auto_courtyards(grid, empty_code=0, courtyard_code=4)
array([[0, 0, 0, 0],
       [0, 2, 2, 0],
       [0, 2, 4, 0],
       [0, 0, 0, 0]], dtype=uint8)