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pythongeopandasr-sfrpy2shapely
Tim
Tim

Reputation: 583

st_make_grid method equivalent in python

Is there an equivalent to the very good st_make_grid method of the sf package from r-spatial in python? The method create rectangular grid geometry over the bounding box of a polygon.

I would like to do exactly the same as the solution proposed in this question, e.g. divide a polygon into several squares of the same area that I choose. Thanks for your help.

Alternatively, I could use rpy2 to run a script in r that executes the st_make_grid method which takes a shapely polygon as input and outputs the square polygons, to be read with shapely. Would this be effective on many polygons to process?

Upvotes: 3

Views: 2112

Answers (1)

martinfleis
martinfleis

Reputation: 7814

Would this be effective on many polygons to process?

Certainly not. There's no built-in Python version but the function below does the trick. If you need performance, make sure that you have pygeos installed in your environment.

def make_grid(polygon, edge_size):
    """
    polygon : shapely.geometry
    edge_size : length of the grid cell
    """
    from itertools import product
    import numpy as np
    import geopandas as gpd
    
    bounds = polygon.bounds
    x_coords = np.arange(bounds[0] + edge_size/2, bounds[2], edge_size)
    y_coords = np.arange(bounds[1] + edge_size/2, bounds[3], edge_size)
    combinations = np.array(list(product(x_coords, y_coords)))
    squares = gpd.points_from_xy(combinations[:, 0], combinations[:, 1]).buffer(edge_size / 2, cap_style=3)
    return gpd.GeoSeries(squares[squares.intersects(polygon)])

Upvotes: 4

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