Created
November 15, 2025 12:57
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| import numpy as np | |
| import shapely | |
| from typing import Callable | |
| maxc = 20037508.342789244 | |
| sidelength: Callable[[int], float] = lambda z: 2 * maxc / (2**z) | |
| def get_tile_centres(z: int, x: int, y: int) -> tuple[float, float]: | |
| # return coordinates of tile centres in EPSG:3857 | |
| x = -maxc + maxc / (2**z) + sidelength(z) * x | |
| y = maxc - maxc / (2**z) - sidelength(z) * y | |
| return x, y | |
| def get_tile_corners(z: int, x: int, y: int): | |
| tc = get_tile_centres(z, x, y) | |
| s = sidelength(z) | |
| corners = [] | |
| for each in [[1, 1], [1, -1], [-1, -1], [-1, 1], [1, 1]]: | |
| v = 0.5 * np.array([each]) * np.array([s, s]) | |
| corner = tc + v | |
| corners.append(corner) | |
| corners = np.squeeze(corners) | |
| p = shapely.geometry.Polygon(corners) | |
| return p | |
| minx, miny, maxx, maxy = get_tile_corners(z, x, y).bounds | |
| print(f"{minx}, {maxy}, {maxx}, {miny}") |
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