shapely.coverage_union_all

coverage_union_all(geometries, axis=None, **kwargs)

Returns the union of multiple polygons of a geometry collection. This is an optimized version of union which assumes the polygons to be non-overlapping.

Note

‘coverage_union_all’ requires at least GEOS 3.8.0.

This function ignores None values when other Geometry elements are present. If all elements of the given axis are None, an empty MultiPolygon is returned.

Parameters:

geometriesarray_like

axisint, optional

Axis along which the operation is performed. The default (None) performs the operation over all axes, returning a scalar value. Axis may be negative, in which case it counts from the last to the first axis.

**kwargs

For other keyword-only arguments, see the NumPy ufunc docs.

See also

coverage_union

Examples

>>> from shapely import normalize, Polygon
>>> polygon_1 = Polygon([(0, 0), (0, 1), (1, 1), (1, 0), (0, 0)])
>>> polygon_2 = Polygon([(1, 0), (1, 1), (2, 1), (2, 0), (1, 0)])
>>> normalize(coverage_union_all([polygon_1, polygon_2]))
<POLYGON ((0 0, 0 1, 1 1, 2 1, 2 0, 1 0, 0 0))>
>>> normalize(coverage_union_all([polygon_1, None]))
<POLYGON ((0 0, 0 1, 1 1, 1 0, 0 0))>
>>> normalize(coverage_union_all([None, None]))
<MULTIPOLYGON EMPTY>