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Merge pull request #678 from martinfleis/voronoi
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ENH: geometry agnostic Voronoi based on shapely
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@ljwolf
ljwolf committed Mar 1, 2024
2 parents 24f2e72 + 018f1e2 commit a7779f7
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201 changes: 195 additions & 6 deletions libpysal/cg/tests/test_voronoi.py
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Original file line number Diff line number Diff line change
@@ -1,12 +1,17 @@
import geopandas as gpd
import numpy as np
import pytest
import shapely
from geopandas.testing import assert_geoseries_equal
from packaging.version import Version

from ..shapes import Polygon, asShape
from ..voronoi import voronoi, voronoi_frames


class TestVoronoi:
def setup_method(self):
self.points = [(10.2, 5.1), (4.7, 2.2), (5.3, 5.7), (2.7, 5.3)]
self.points2 = [(10, 5), (4, 2), (5, 5)]

self.vertices = [
[4.21783295711061, 4.084085778781038],
Expand All @@ -21,13 +26,197 @@ def setup_method(self):
[-9.226913414477298, -4.58994413837245],
]

p1 = shapely.Polygon([(0, 0), (0, 1), (1, 1), (1, 0)])
p2 = shapely.Polygon([(0, 1), (0, 2), (1, 2), (1, 1)])
p3 = shapely.Polygon([(1, 1), (1, 2), (2, 2), (2, 1)])
p4 = shapely.Polygon([(1, 0), (1, 1), (2, 1), (2, 0)])
self.polygons = gpd.GeoSeries([p1, p2, p3, p4], crs="EPSG:3857")

self.lines = gpd.GeoSeries(
[
shapely.LineString([(0, 0), (0, 1)]),
shapely.LineString([(1, 1), (1, 0)]),
],
crs="EPSG:3857",
)

def test_voronoi(self):
regions, vertices = voronoi(self.points)
with pytest.warns(
FutureWarning, match="The 'voronoi' function is considered private"
):
regions, vertices = voronoi(self.points)
assert regions == [[1, 3, 2], [4, 5, 1, 0], [0, 1, 7, 6], [9, 0, 8]]

np.testing.assert_array_almost_equal(vertices, self.vertices)

def test_voronoi_frames(self):
r_df, p_df = voronoi_frames(self.points)
region = r_df.iloc[0]["geometry"]
assert isinstance(asShape(region), Polygon)
def test_from_array(self):
geoms = voronoi_frames(self.points2, as_gdf=False, return_input=False)
expected = gpd.GeoSeries.from_wkt(
[
"POLYGON ((7.5 2.5, 7.5 5, 10 5, 10 2, 7.75 2, 7.5 2.5))",
"POLYGON ((7.5 2.5, 7.75 2, 4 2, 4 3.66666666, 7.5 2.5))",
"POLYGON ((7.5 2.5, 4 3.66666666, 4 5, 7.5 5, 7.5 2.5))",
],
)
assert_geoseries_equal(
shapely.normalize(geoms),
shapely.normalize(expected),
check_less_precise=True,
)

def test_from_polygons(self):
geoms = voronoi_frames(
self.polygons, as_gdf=False, return_input=False, shrink=0.1
)
expected = gpd.GeoSeries.from_wkt(
[
"POLYGON ((0.5 1, 1 1, 1 0.5, 1 0.1, 0.1 0.1, 0.1 1, 0.5 1))",
"POLYGON ((1 1.5, 1 1, 0.5 1, 0.1 1, 0.1 1.9, 1 1.9, 1 1.5))",
"POLYGON ((1 1.5, 1 1.9, 1.9 1.9, 1.9 1, 1.5 1, 1 1, 1 1.5))",
"POLYGON ((1 0.5, 1 1, 1.5 1, 1.9 1, 1.9 0.1, 1 0.1, 1 0.5))",
],
crs="EPSG:3857",
)
assert_geoseries_equal(
shapely.normalize(geoms),
shapely.normalize(expected),
check_less_precise=True,
)

@pytest.mark.skipif(
Version(gpd.__version__) < Version("0.13.0"),
reason="requires geopandas>=0.13.0",
)
def test_from_lines(self):
geoms = voronoi_frames(
self.lines, as_gdf=False, return_input=False, segment=0.1
)
expected = gpd.GeoSeries.from_wkt(
[
"POLYGON ((0.5 0.95, 0.5 0, 0 0, 0 1, 0.5 0.95))",
"POLYGON ((0.5 0.05, 0.5 1, 1 1, 1 0, 0.5 0.05))",
],
crs="EPSG:3857",
)
assert_geoseries_equal(geoms.simplify(0.1), expected, check_less_precise=True)

@pytest.mark.skipif(
Version(gpd.__version__) >= Version("0.13.0"),
reason="requires geopandas<0.13.0",
)
def test_from_lines_import_error(self):
with pytest.raises(
ImportError,
match="Voronoi tessellation of lines requires geopandas 0.13.0 or later.",
):
voronoi_frames(self.lines, as_gdf=False, return_input=False, segment=0.1)

def test_clip_none(self):
geoms = voronoi_frames(
self.points2, as_gdf=False, return_input=False, clip=None
)
expected = gpd.GeoSeries.from_wkt(
[
"POLYGON ((16 11, 16 -4, 10.75 -4, 7.5 2.5, 7.5 11, 16 11))",
"POLYGON ((-2 -4, -2 5.6666666, 7.5 2.5, 10.75 -4, -2 -4))",
"POLYGON ((-2 11, 7.5 11, 7.5 2.5, -2 5.66666666, -2 11))",
],
)
assert_geoseries_equal(
shapely.normalize(geoms),
shapely.normalize(expected),
check_less_precise=True,
)

def test_clip_chull(self):
geoms = voronoi_frames(
self.points2, as_gdf=False, return_input=False, clip="convex_hull"
)
expected = gpd.GeoSeries.from_wkt(
[
"POLYGON ((7.5 5, 10 5, 7.5 3.75, 7.5 5))",
"POLYGON ((6 3, 4 2, 4.5 3.5, 6 3))",
"POLYGON ((7.5 3.75, 6 3, 4.5 3.5, 5 5, 7.5 5, 7.5 3.75))",
],
)
assert_geoseries_equal(
shapely.normalize(geoms),
shapely.normalize(expected),
check_less_precise=True,
)

def test_clip_ahull(self):
geoms = voronoi_frames(
self.points2, as_gdf=False, return_input=False, clip="alpha_shape"
)
expected = gpd.GeoSeries.from_wkt(
[
"POLYGON ((7.5 5, 10 5, 7.5 3.75, 7.5 5))",
"POLYGON ((6 3, 4 2, 4.5 3.5, 6 3))",
"POLYGON ((7.5 3.75, 6 3, 4.5 3.5, 5 5, 7.5 5, 7.5 3.75))",
],
)
assert_geoseries_equal(
shapely.normalize(geoms),
shapely.normalize(expected),
check_less_precise=True,
)

def test_clip_polygon(self):
geoms = voronoi_frames(
self.points2,
as_gdf=False,
return_input=False,
clip=shapely.box(-10, -10, 10, 10),
)
expected = gpd.GeoSeries.from_wkt(
[
"POLYGON ((7.5 2.5, 7.5 10, 10 10, 10 -2.5, 7.5 2.5))",
"POLYGON ("
"(-10 8.333333, 7.5 2.5, 10 -2.5, 10 -10, -10 -10, -10 8.333333))",
"POLYGON ((7.5 2.5, -10 8.33333333, -10 10, 7.5 10, 7.5 2.5))",
],
)
assert_geoseries_equal(
shapely.normalize(geoms),
shapely.normalize(expected),
check_less_precise=True,
)

def test_clip_error(self):
with pytest.raises(ValueError, match="Clip type 'invalid' not understood."):
voronoi_frames(self.points2, clip="invalid")

def test_as_gdf(self):
geoms, polys = voronoi_frames(self.polygons, as_gdf=True, return_input=True)
assert isinstance(geoms, gpd.GeoDataFrame)
assert isinstance(polys, gpd.GeoDataFrame)

with pytest.warns(
FutureWarning,
match="The 'as_gdf' parameter currently defaults to True but will",
):
voronoi_frames(self.points2, return_input=True)

def test_return_input(self):
geoms, polys = voronoi_frames(self.polygons, return_input=True, as_gdf=False)
assert isinstance(geoms, gpd.GeoSeries)
assert polys is self.polygons

with pytest.warns(
FutureWarning,
match="The 'return_input' parameter currently defaults to True but will",
):
voronoi_frames(self.points2, as_gdf=True)

def test_radius(self):
with pytest.warns(FutureWarning, match="The 'radius' parameter is deprecated"):
voronoi_frames(self.points2, radius=1)

@pytest.mark.parametrize("clip", ["none", "bounds", "chull", "ahull"])
def test_deprecated_clip(self, clip):
with pytest.warns(
FutureWarning,
match=f"The '{clip}' option for the 'clip' parameter is deprecated",
):
voronoi_frames(self.points2, clip=clip)

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