import unittest import pytest from shapely.errors import GeometryTypeError from shapely.geometry import ( LineString, MultiLineString, MultiPoint, MultiPolygon, Point, Polygon, ) from shapely.ops import linemerge, split, unary_union class TestSplitGeometry(unittest.TestCase): # helper class for testing below def helper(self, geom, splitter, expected_chunks): s = split(geom, splitter) assert s.geom_type == "GeometryCollection" assert len(s.geoms) == expected_chunks if expected_chunks > 1: # split --> expected collection that when merged is again equal to original # geometry if s.geoms[0].geom_type == "LineString": self.assertTrue(linemerge(s).simplify(0.000001).equals(geom)) elif s.geoms[0].geom_type == "Polygon": union = unary_union(s).simplify(0.000001) assert union.equals(geom) assert union.area == geom.area else: raise ValueError elif expected_chunks == 1: # not split --> expected equal to line assert s.geoms[0].equals(geom) def test_split_closed_line_with_point(self): # point at start/end of closed ring -> return equal # see GH #524 ls = LineString([(0, 0), (0, 1), (1, 1), (1, 0), (0, 0)]) splitter = Point(0, 0) self.helper(ls, splitter, 1) class TestSplitPolygon(TestSplitGeometry): poly_simple = Polygon([(0, 0), (2, 0), (2, 2), (0, 2), (0, 0)]) poly_hole = Polygon( [(0, 0), (2, 0), (2, 2), (0, 2), (0, 0)], [[(0.5, 0.5), (0.5, 1.5), (1.5, 1.5), (1.5, 0.5), (0.5, 0.5)]], ) def test_split_poly_with_line(self): # crossing at 2 points --> return 2 polygons splitter = LineString([(1, 3), (1, -3)]) self.helper(self.poly_simple, splitter, 2) self.helper(self.poly_hole, splitter, 2) # crossing twice with one linestring --> return 3 polygons splitter = LineString([(1, 3), (1, -3), (1.7, -3), (1.7, 3)]) self.helper(self.poly_simple, splitter, 3) self.helper(self.poly_hole, splitter, 3) # touching the boundary --> return equal splitter = LineString([(0, 2), (5, 2)]) self.helper(self.poly_simple, splitter, 1) self.helper(self.poly_hole, splitter, 1) # inside the polygon --> return equal splitter = LineString([(0.2, 0.2), (1.7, 1.7), (3, 2)]) self.helper(self.poly_simple, splitter, 1) self.helper(self.poly_hole, splitter, 1) # outside the polygon --> return equal splitter = LineString([(0, 3), (3, 3), (3, 0)]) self.helper(self.poly_simple, splitter, 1) self.helper(self.poly_hole, splitter, 1) def test_split_poly_with_multiline(self): # crossing twice with a multilinestring --> return 3 polygons splitter = MultiLineString([[(0.2, 3), (0.2, -3)], [(1.7, -3), (1.7, 3)]]) self.helper(self.poly_simple, splitter, 3) self.helper(self.poly_hole, splitter, 3) # crossing twice with a cross multilinestring --> return 4 polygons splitter = MultiLineString([[(0.2, 3), (0.2, -3)], [(-3, 1), (3, 1)]]) self.helper(self.poly_simple, splitter, 4) self.helper(self.poly_hole, splitter, 4) # cross once, touch the boundary once --> return 2 polygons splitter = MultiLineString([[(0.2, 3), (0.2, -3)], [(0, 2), (5, 2)]]) self.helper(self.poly_simple, splitter, 2) self.helper(self.poly_hole, splitter, 2) # cross once, inside the polygon once --> return 2 polygons splitter = MultiLineString( [[(0.2, 3), (0.2, -3)], [(1.2, 1.2), (1.7, 1.7), (3, 2)]] ) self.helper(self.poly_simple, splitter, 2) self.helper(self.poly_hole, splitter, 2) # cross once, outside the polygon once --> return 2 polygons splitter = MultiLineString([[(0.2, 3), (0.2, -3)], [(0, 3), (3, 3), (3, 0)]]) self.helper(self.poly_simple, splitter, 2) self.helper(self.poly_hole, splitter, 2) def test_split_poly_with_other(self): with pytest.raises(GeometryTypeError): split(self.poly_simple, Point(1, 1)) with pytest.raises(GeometryTypeError): split(self.poly_simple, MultiPoint([(1, 1), (3, 4)])) with pytest.raises(GeometryTypeError): split(self.poly_simple, self.poly_hole) class TestSplitLine(TestSplitGeometry): ls = LineString([(0, 0), (1.5, 1.5), (3.0, 4.0)]) def test_split_line_with_point(self): # point on line interior --> return 2 segments splitter = Point(1, 1) self.helper(self.ls, splitter, 2) # point on line point --> return 2 segments splitter = Point(1.5, 1.5) self.helper(self.ls, splitter, 2) # point on boundary --> return equal splitter = Point(3, 4) self.helper(self.ls, splitter, 1) # point on exterior of line --> return equal splitter = Point(2, 2) self.helper(self.ls, splitter, 1) def test_split_line_with_multipoint(self): # points on line interior --> return 4 segments splitter = MultiPoint([(1, 1), (1.5, 1.5), (0.5, 0.5)]) self.helper(self.ls, splitter, 4) # points on line interior and boundary -> return 2 segments splitter = MultiPoint([(1, 1), (3, 4)]) self.helper(self.ls, splitter, 2) # point on linear interior but twice --> return 2 segments splitter = MultiPoint([(1, 1), (1.5, 1.5), (1, 1)]) self.helper(self.ls, splitter, 3) def test_split_line_with_line(self): # crosses at one point --> return 2 segments splitter = LineString([(0, 1), (1, 0)]) self.helper(self.ls, splitter, 2) # crosses at two points --> return 3 segments splitter = LineString([(0, 1), (1, 0), (1, 2)]) self.helper(self.ls, splitter, 3) # overlaps --> raise splitter = LineString([(0, 0), (15, 15)]) with pytest.raises(ValueError): self.helper(self.ls, splitter, 1) # does not cross --> return equal splitter = LineString([(0, 1), (0, 2)]) self.helper(self.ls, splitter, 1) # is touching the boundary --> return equal splitter = LineString([(-1, 1), (1, -1)]) assert splitter.touches(self.ls) self.helper(self.ls, splitter, 1) # splitter boundary touches interior of line --> return 2 segments splitter = LineString([(0, 1), (1, 1)]) # touches at (1, 1) assert splitter.touches(self.ls) self.helper(self.ls, splitter, 2) def test_split_line_with_multiline(self): # crosses at one point --> return 2 segments splitter = MultiLineString([[(0, 1), (1, 0)], [(0, 0), (2, -2)]]) self.helper(self.ls, splitter, 2) # crosses at two points --> return 3 segments splitter = MultiLineString([[(0, 1), (1, 0)], [(0, 2), (2, 0)]]) self.helper(self.ls, splitter, 3) # crosses at three points --> return 4 segments splitter = MultiLineString([[(0, 1), (1, 0)], [(0, 2), (2, 0), (2.2, 3.2)]]) self.helper(self.ls, splitter, 4) # overlaps --> raise splitter = MultiLineString([[(0, 0), (1.5, 1.5)], [(1.5, 1.5), (3, 4)]]) with pytest.raises(ValueError): self.helper(self.ls, splitter, 1) # does not cross --> return equal splitter = MultiLineString([[(0, 1), (0, 2)], [(1, 0), (2, 0)]]) self.helper(self.ls, splitter, 1) def test_split_line_with_polygon(self): # crosses at two points --> return 3 segments splitter = Polygon([(1, 0), (1, 2), (2, 2), (2, 0), (1, 0)]) self.helper(self.ls, splitter, 3) # crosses at one point and touches boundary --> return 2 segments splitter = Polygon([(0, 0), (1, 2), (2, 2), (1, 0), (0, 0)]) self.helper(self.ls, splitter, 2) # exterior crosses at one point and touches at (0, 0) # interior crosses at two points splitter = Polygon( [(0, 0), (2, 0), (2, 2), (0, 2), (0, 0)], [[(0.5, 0.5), (0.5, 1.5), (1.5, 1.5), (1.5, 0.5), (0.5, 0.5)]], ) self.helper(self.ls, splitter, 4) def test_split_line_with_multipolygon(self): poly1 = Polygon( [(0, 0), (2, 0), (2, 2), (0, 2), (0, 0)] ) # crosses at one point and touches at (0, 0) poly2 = Polygon( [(0.5, 0.5), (0.5, 1.5), (1.5, 1.5), (1.5, 0.5), (0.5, 0.5)] ) # crosses at two points poly3 = Polygon([(0, 0), (0, -2), (-2, -2), (-2, 0), (0, 0)]) # not crossing splitter = MultiPolygon([poly1, poly2, poly3]) self.helper(self.ls, splitter, 4) class TestSplitClosedRing(TestSplitGeometry): ls = LineString([[0, 0], [0, 1], [1, 1], [1, 0], [0, 0]]) def test_split_closed_ring_with_point(self): splitter = Point([0.0, 0.0]) self.helper(self.ls, splitter, 1) splitter = Point([0.0, 0.5]) self.helper(self.ls, splitter, 2) result = split(self.ls, splitter) assert result.geoms[0].coords[:] == [(0, 0), (0.0, 0.5)] assert result.geoms[1].coords[:] == [(0.0, 0.5), (0, 1), (1, 1), (1, 0), (0, 0)] # previously failed, see GH#585 splitter = Point([0.5, 0.0]) self.helper(self.ls, splitter, 2) result = split(self.ls, splitter) assert result.geoms[0].coords[:] == [(0, 0), (0, 1), (1, 1), (1, 0), (0.5, 0)] assert result.geoms[1].coords[:] == [(0.5, 0), (0, 0)] splitter = Point([2.0, 2.0]) self.helper(self.ls, splitter, 1) class TestSplitMulti(TestSplitGeometry): def test_split_multiline_with_point(self): # a cross-like multilinestring with a point in the middle --> return 4 line # segments l1 = LineString([(0, 1), (2, 1)]) l2 = LineString([(1, 0), (1, 2)]) ml = MultiLineString([l1, l2]) splitter = Point((1, 1)) self.helper(ml, splitter, 4) def test_split_multiline_with_multipoint(self): # a cross-like multilinestring with a point in middle, a point on one of the # lines and a point in the exterior # --> return 4+1 line segments l1 = LineString([(0, 1), (3, 1)]) l2 = LineString([(1, 0), (1, 2)]) ml = MultiLineString([l1, l2]) splitter = MultiPoint([(1, 1), (2, 1), (4, 2)]) self.helper(ml, splitter, 5) def test_split_multipolygon_with_line(self): # two polygons with a crossing line --> return 4 triangles poly1 = Polygon([(0, 0), (1, 0), (1, 1), (0, 1), (0, 0)]) poly2 = Polygon([(1, 1), (1, 2), (2, 2), (2, 1), (1, 1)]) mpoly = MultiPolygon([poly1, poly2]) ls = LineString([(-1, -1), (3, 3)]) self.helper(mpoly, ls, 4) # two polygons away from the crossing line --> return identity poly1 = Polygon([(10, 10), (10, 11), (11, 11), (11, 10), (10, 10)]) poly2 = Polygon([(-10, -10), (-10, -11), (-11, -11), (-11, -10), (-10, -10)]) mpoly = MultiPolygon([poly1, poly2]) ls = LineString([(-1, -1), (3, 3)]) self.helper(mpoly, ls, 2)