test_geom_methods.py

from __future__ import absolute_import

import string

import numpy as np
from numpy.testing import assert_array_equal
from pandas import DataFrame, MultiIndex, Series

from shapely.geometry import LinearRing, LineString, MultiPoint, Point, Polygon
from shapely.geometry.collection import GeometryCollection
from shapely.ops import unary_union

from geopandas import GeoDataFrame, GeoSeries
from geopandas.base import GeoPandasBase

from geopandas.tests.util import assert_geoseries_equal, geom_almost_equals, geom_equals
from pandas.util.testing import assert_frame_equal, assert_series_equal
import pytest


def assert_array_dtype_equal(a, b, *args, **kwargs):
    a = np.asanyarray(a)
    b = np.asanyarray(b)
    assert a.dtype == b.dtype
    assert_array_equal(a, b, *args, **kwargs)


class TestGeomMethods:
    def setup_method(self):
        self.t1 = Polygon([(0, 0), (1, 0), (1, 1)])
        self.t2 = Polygon([(0, 0), (1, 1), (0, 1)])
        self.t3 = Polygon([(2, 0), (3, 0), (3, 1)])
        self.sq = Polygon([(0, 0), (1, 0), (1, 1), (0, 1)])
        self.inner_sq = Polygon(
            [(0.25, 0.25), (0.75, 0.25), (0.75, 0.75), (0.25, 0.75)]
        )
        self.nested_squares = Polygon(self.sq.boundary, [self.inner_sq.boundary])
        self.p0 = Point(5, 5)
        self.p3d = Point(5, 5, 5)
        self.g0 = GeoSeries(
            [
                self.t1,
                self.t2,
                self.sq,
                self.inner_sq,
                self.nested_squares,
                self.p0,
                None,
            ]
        )
        self.g1 = GeoSeries([self.t1, self.sq])
        self.g2 = GeoSeries([self.sq, self.t1])
        self.g3 = GeoSeries([self.t1, self.t2])
        self.g3.crs = {"init": "epsg:4326", "no_defs": True}
        self.g4 = GeoSeries([self.t2, self.t1])
        self.g4.crs = {"init": "epsg:4326", "no_defs": True}
        self.g_3d = GeoSeries([self.p0, self.p3d])
        self.na = GeoSeries([self.t1, self.t2, Polygon()])
        self.na_none = GeoSeries([self.t1, None])
        self.a1 = self.g1.copy()
        self.a1.index = ["A", "B"]
        self.a2 = self.g2.copy()
        self.a2.index = ["B", "C"]
        self.esb = Point(-73.9847, 40.7484)
        self.sol = Point(-74.0446, 40.6893)
        self.landmarks = GeoSeries(
            [self.esb, self.sol], crs={"init": "epsg:4326", "no_defs": True}
        )
        self.l1 = LineString([(0, 0), (0, 1), (1, 1)])
        self.l2 = LineString([(0, 0), (1, 0), (1, 1), (0, 1)])
        self.g5 = GeoSeries([self.l1, self.l2])
        self.g6 = GeoSeries([self.p0, self.t3])
        self.empty = GeoSeries([])
        self.all_none = GeoSeries([None, None])
        self.empty_poly = Polygon()

        # Crossed lines
        self.l3 = LineString([(0, 0), (1, 1)])
        self.l4 = LineString([(0, 1), (1, 0)])
        self.crossed_lines = GeoSeries([self.l3, self.l4])

        # Placeholder for testing, will just drop in different geometries
        # when needed
        self.gdf1 = GeoDataFrame(
            {"geometry": self.g1, "col0": [1.0, 2.0], "col1": ["geo", "pandas"]}
        )
        self.gdf2 = GeoDataFrame(
            {"geometry": self.g1, "col3": [4, 5], "col4": ["rand", "string"]}
        )

    def _test_unary_real(self, op, expected, a):
        """ Tests for 'area', 'length', 'is_valid', etc. """
        fcmp = assert_series_equal
        self._test_unary(op, expected, a, fcmp)

    def _test_unary_topological(self, op, expected, a):
        if isinstance(expected, GeoPandasBase):
            fcmp = assert_geoseries_equal
        else:

            def fcmp(a, b):
                assert a.equals(b)

        self._test_unary(op, expected, a, fcmp)

    def _test_binary_topological(self, op, expected, a, b, *args, **kwargs):
        """ Tests for 'intersection', 'union', 'symmetric_difference', etc. """
        if isinstance(expected, GeoPandasBase):
            fcmp = assert_geoseries_equal
        else:

            def fcmp(a, b):
                assert geom_equals(a, b)

        if isinstance(b, GeoPandasBase):
            right_df = True
        else:
            right_df = False

        self._binary_op_test(op, expected, a, b, fcmp, True, right_df, *args, **kwargs)

    def _test_binary_real(self, op, expected, a, b, *args, **kwargs):
        fcmp = assert_series_equal
        self._binary_op_test(op, expected, a, b, fcmp, True, False, *args, **kwargs)

    def _test_binary_operator(self, op, expected, a, b):
        """
        The operators only have GeoSeries on the left, but can have
        GeoSeries or GeoDataFrame on the right.

        """
        if isinstance(expected, GeoPandasBase):
            fcmp = assert_geoseries_equal
        else:

            def fcmp(a, b):
                assert geom_equals(a, b)

        if isinstance(b, GeoPandasBase):
            right_df = True
        else:
            right_df = False

        self._binary_op_test(op, expected, a, b, fcmp, False, right_df)

    def _binary_op_test(
        self, op, expected, left, right, fcmp, left_df, right_df, *args, **kwargs
    ):
        """
        This is a helper to call a function on GeoSeries and GeoDataFrame
        arguments. For example, 'intersection' is a member of both GeoSeries
        and GeoDataFrame and can take either GeoSeries or GeoDataFrame inputs.
        This function has the ability to test all four combinations of input
        types.

        Parameters
        ----------

        expected : str
            The operation to be tested. e.g., 'intersection'
        left: GeoSeries
        right: GeoSeries
        fcmp: function
            Called with the result of the operation and expected. It should
            assert if the result is incorrect
        left_df: bool
            If the left input should also be called with a GeoDataFrame
        right_df: bool
            Indicates whether the right input should be called with a
            GeoDataFrame

        """

        def _make_gdf(s):
            n = len(s)
            col1 = string.ascii_lowercase[:n]
            col2 = range(n)

            return GeoDataFrame(
                {"geometry": s.values, "col1": col1, "col2": col2},
                index=s.index,
                crs=s.crs,
            )

        # Test GeoSeries.op(GeoSeries)
        result = getattr(left, op)(right, *args, **kwargs)
        fcmp(result, expected)

        if left_df:
            # Test GeoDataFrame.op(GeoSeries)
            gdf_left = _make_gdf(left)
            result = getattr(gdf_left, op)(right, *args, **kwargs)
            fcmp(result, expected)

        if right_df:
            # Test GeoSeries.op(GeoDataFrame)
            gdf_right = _make_gdf(right)
            result = getattr(left, op)(gdf_right, *args, **kwargs)
            fcmp(result, expected)

            if left_df:
                # Test GeoDataFrame.op(GeoDataFrame)
                result = getattr(gdf_left, op)(gdf_right, *args, **kwargs)
                fcmp(result, expected)

    def _test_unary(self, op, expected, a, fcmp):
        # GeoSeries, (GeoSeries or geometry)
        result = getattr(a, op)
        fcmp(result, expected)

        # GeoDataFrame, (GeoSeries or geometry)
        gdf = self.gdf1.set_geometry(a)
        result = getattr(gdf, op)
        fcmp(result, expected)

    # TODO reenable for all operations once we use pyproj > 2
    # def test_crs_warning(self):
    #     # operations on geometries should warn for different CRS
    #     no_crs_g3 = self.g3.copy()
    #     no_crs_g3.crs = None
    #     with pytest.warns(UserWarning):
    #         self._test_binary_topological('intersection', self.g3,
    #                                       self.g3, no_crs_g3)

    def test_intersection(self):
        self._test_binary_topological("intersection", self.t1, self.g1, self.g2)
        self._test_binary_topological(
            "intersection", self.all_none, self.g1, self.empty
        )

    def test_union_series(self):
        self._test_binary_topological("union", self.sq, self.g1, self.g2)

    def test_union_polygon(self):
        self._test_binary_topological("union", self.sq, self.g1, self.t2)

    def test_symmetric_difference_series(self):
        self._test_binary_topological("symmetric_difference", self.sq, self.g3, self.g4)

    def test_symmetric_difference_poly(self):
        expected = GeoSeries([GeometryCollection(), self.sq], crs=self.g3.crs)
        self._test_binary_topological(
            "symmetric_difference", expected, self.g3, self.t1
        )

    def test_difference_series(self):
        expected = GeoSeries([GeometryCollection(), self.t2])
        self._test_binary_topological("difference", expected, self.g1, self.g2)

    def test_difference_poly(self):
        expected = GeoSeries([self.t1, self.t1])
        self._test_binary_topological("difference", expected, self.g1, self.t2)

    def test_geo_op_empty_result(self):
        l1 = LineString([(0, 0), (1, 1)])
        l2 = LineString([(2, 2), (3, 3)])
        expected = GeoSeries([GeometryCollection()])
        # binary geo resulting in empty geometry
        result = GeoSeries([l1]).intersection(l2)
        assert_geoseries_equal(result, expected)
        # binary geo empty result with right GeoSeries
        result = GeoSeries([l1]).intersection(GeoSeries([l2]))
        assert_geoseries_equal(result, expected)
        # unary geo resulting in emtpy geometry
        result = GeoSeries([GeometryCollection()]).convex_hull
        assert_geoseries_equal(result, expected)

    def test_boundary(self):
        l1 = LineString([(0, 0), (1, 0), (1, 1), (0, 0)])
        l2 = LineString([(0, 0), (1, 0), (1, 1), (0, 1), (0, 0)])
        expected = GeoSeries([l1, l2], index=self.g1.index, crs=self.g1.crs)

        self._test_unary_topological("boundary", expected, self.g1)

    def test_area(self):
        expected = Series(np.array([0.5, 1.0]), index=self.g1.index)
        self._test_unary_real("area", expected, self.g1)

        expected = Series(np.array([0.5, np.nan]), index=self.na_none.index)
        self._test_unary_real("area", expected, self.na_none)

    def test_bounds(self):
        # Set columns to get the order right
        expected = DataFrame(
            {
                "minx": [0.0, 0.0],
                "miny": [0.0, 0.0],
                "maxx": [1.0, 1.0],
                "maxy": [1.0, 1.0],
            },
            index=self.g1.index,
            columns=["minx", "miny", "maxx", "maxy"],
        )

        result = self.g1.bounds
        assert_frame_equal(expected, result)

        gdf = self.gdf1.set_geometry(self.g1)
        result = gdf.bounds
        assert_frame_equal(expected, result)

    def test_bounds_empty(self):
        # test bounds of empty GeoSeries
        # https://github.com/geopandas/geopandas/issues/1195
        s = GeoSeries([])
        result = s.bounds
        expected = DataFrame(
            columns=["minx", "miny", "maxx", "maxy"], index=s.index, dtype="float64"
        )
        assert_frame_equal(result, expected)

    def test_unary_union(self):
        p1 = self.t1
        p2 = Polygon([(2, 0), (3, 0), (3, 1)])
        expected = unary_union([p1, p2])
        g = GeoSeries([p1, p2])

        self._test_unary_topological("unary_union", expected, g)

    def test_contains(self):
        expected = [True, False, True, False, False, False, False]
        assert_array_dtype_equal(expected, self.g0.contains(self.t1))

    def test_length(self):
        expected = Series(np.array([2 + np.sqrt(2), 4]), index=self.g1.index)
        self._test_unary_real("length", expected, self.g1)

        expected = Series(np.array([2 + np.sqrt(2), np.nan]), index=self.na_none.index)
        self._test_unary_real("length", expected, self.na_none)

    def test_crosses(self):
        expected = [False, False, False, False, False, False, False]
        assert_array_dtype_equal(expected, self.g0.crosses(self.t1))

        expected = [False, True]
        assert_array_dtype_equal(expected, self.crossed_lines.crosses(self.l3))

    def test_disjoint(self):
        expected = [False, False, False, False, False, True, False]
        assert_array_dtype_equal(expected, self.g0.disjoint(self.t1))

    def test_relate(self):
        expected = Series(
            [
                "212101212",
                "212101212",
                "212FF1FF2",
                "2FFF1FFF2",
                "FF2F112F2",
                "FF0FFF212",
                None,
            ],
            index=self.g0.index,
        )
        assert_array_dtype_equal(expected, self.g0.relate(self.inner_sq))

        expected = Series(["FF0FFF212", None], index=self.g6.index)
        assert_array_dtype_equal(expected, self.g6.relate(self.na_none))

    def test_distance(self):
        expected = Series(
            np.array([np.sqrt((5 - 1) ** 2 + (5 - 1) ** 2), np.nan]), self.na_none.index
        )
        assert_array_dtype_equal(expected, self.na_none.distance(self.p0))

        expected = Series(np.array([np.sqrt(4 ** 2 + 4 ** 2), np.nan]), self.g6.index)
        assert_array_dtype_equal(expected, self.g6.distance(self.na_none))

    def test_intersects(self):
        expected = [True, True, True, True, True, False, False]
        assert_array_dtype_equal(expected, self.g0.intersects(self.t1))

        expected = [True, False]
        assert_array_dtype_equal(expected, self.na_none.intersects(self.t2))

        expected = np.array([], dtype=bool)
        assert_array_dtype_equal(expected, self.empty.intersects(self.t1))

        expected = np.array([], dtype=bool)
        assert_array_dtype_equal(expected, self.empty.intersects(self.empty_poly))

        expected = [False] * 7
        assert_array_dtype_equal(expected, self.g0.intersects(self.empty_poly))

    def test_overlaps(self):
        expected = [True, True, False, False, False, False, False]
        assert_array_dtype_equal(expected, self.g0.overlaps(self.inner_sq))

        expected = [False, False]
        assert_array_dtype_equal(expected, self.g4.overlaps(self.t1))

    def test_touches(self):
        expected = [False, True, False, False, False, False, False]
        assert_array_dtype_equal(expected, self.g0.touches(self.t1))

    def test_within(self):
        expected = [True, False, False, False, False, False, False]
        assert_array_dtype_equal(expected, self.g0.within(self.t1))

        expected = [True, True, True, True, True, False, False]
        assert_array_dtype_equal(expected, self.g0.within(self.sq))

    def test_is_valid(self):
        expected = Series(np.array([True] * len(self.g1)), self.g1.index)
        self._test_unary_real("is_valid", expected, self.g1)

    def test_is_empty(self):
        expected = Series(np.array([False] * len(self.g1)), self.g1.index)
        self._test_unary_real("is_empty", expected, self.g1)

    def test_is_ring(self):
        expected = Series(np.array([True] * len(self.g1)), self.g1.index)
        self._test_unary_real("is_ring", expected, self.g1)

    def test_is_simple(self):
        expected = Series(np.array([True] * len(self.g1)), self.g1.index)
        self._test_unary_real("is_simple", expected, self.g1)

    def test_has_z(self):
        expected = Series([False, True], self.g_3d.index)
        self._test_unary_real("has_z", expected, self.g_3d)

    def test_xy_points(self):
        expected_x = [-73.9847, -74.0446]
        expected_y = [40.7484, 40.6893]

        assert_array_dtype_equal(expected_x, self.landmarks.geometry.x)
        assert_array_dtype_equal(expected_y, self.landmarks.geometry.y)

    def test_xy_polygons(self):
        # accessing x attribute in polygon geoseries should raise an error
        with pytest.raises(ValueError):
            _ = self.gdf1.geometry.x
        # and same for accessing y attribute in polygon geoseries
        with pytest.raises(ValueError):
            _ = self.gdf1.geometry.y

    def test_centroid(self):
        polygon = Polygon([(-1, -1), (1, -1), (1, 1), (-1, 1)])
        point = Point(0, 0)
        polygons = GeoSeries([polygon for i in range(3)])
        points = GeoSeries([point for i in range(3)])
        assert_geoseries_equal(polygons.centroid, points)

    def test_convex_hull(self):
        # the convex hull of a square should be the same as the square
        squares = GeoSeries([self.sq for i in range(3)])
        assert_geoseries_equal(squares, squares.convex_hull)

    def test_exterior(self):
        exp_exterior = GeoSeries([LinearRing(p.boundary) for p in self.g3])
        for expected, computed in zip(exp_exterior, self.g3.exterior):
            assert computed.equals(expected)

    def test_interiors(self):
        original = GeoSeries([self.t1, self.nested_squares])

        # This is a polygon with no interior.
        expected = []
        assert original.interiors[0] == expected
        # This is a polygon with an interior.
        expected = LinearRing(self.inner_sq.boundary)
        assert original.interiors[1][0].equals(expected)

    def test_interpolate(self):
        expected = GeoSeries([Point(0.5, 1.0), Point(0.75, 1.0)])
        self._test_binary_topological(
            "interpolate", expected, self.g5, 0.75, normalized=True
        )

        expected = GeoSeries([Point(0.5, 1.0), Point(1.0, 0.5)])
        self._test_binary_topological("interpolate", expected, self.g5, 1.5)

    def test_interpolate_distance_array(self):
        expected = GeoSeries([Point(0.0, 0.75), Point(1.0, 0.5)])
        self._test_binary_topological(
            "interpolate", expected, self.g5, np.array([0.75, 1.5])
        )

        expected = GeoSeries([Point(0.5, 1.0), Point(0.0, 1.0)])
        self._test_binary_topological(
            "interpolate", expected, self.g5, np.array([0.75, 1.5]), normalized=True
        )

    def test_interpolate_distance_wrong_length(self):
        distances = np.array([1, 2, 3])
        with pytest.raises(ValueError):
            self.g5.interpolate(distances)

    def test_interpolate_distance_wrong_index(self):
        distances = Series([1, 2], index=[99, 98])
        with pytest.raises(ValueError):
            self.g5.interpolate(distances)

    def test_project(self):
        expected = Series([2.0, 1.5], index=self.g5.index)
        p = Point(1.0, 0.5)
        self._test_binary_real("project", expected, self.g5, p)

        expected = Series([1.0, 0.5], index=self.g5.index)
        self._test_binary_real("project", expected, self.g5, p, normalized=True)

    def test_affine_transform(self):
        # 45 degree reflection matrix
        matrix = [0, 1, 1, 0, 0, 0]
        expected = self.g4

        res = self.g3.affine_transform(matrix)
        assert_geoseries_equal(expected, res)

    def test_translate_tuple(self):
        trans = self.sol.x - self.esb.x, self.sol.y - self.esb.y
        assert self.landmarks.translate(*trans)[0].equals(self.sol)

        res = self.gdf1.set_geometry(self.landmarks).translate(*trans)[0]
        assert res.equals(self.sol)

    def test_rotate(self):
        angle = 98
        expected = self.g4

        o = Point(0, 0)
        res = self.g4.rotate(angle, origin=o).rotate(-angle, origin=o)
        assert geom_almost_equals(self.g4, res)

        res = self.gdf1.set_geometry(self.g4).rotate(angle, origin=Point(0, 0))
        assert geom_almost_equals(expected, res.rotate(-angle, origin=o))

    def test_scale(self):
        expected = self.g4

        scale = 2.0, 1.0
        inv = tuple(1.0 / i for i in scale)

        o = Point(0, 0)
        res = self.g4.scale(*scale, origin=o).scale(*inv, origin=o)
        assert geom_almost_equals(expected, res)

        res = self.gdf1.set_geometry(self.g4).scale(*scale, origin=o)
        res = res.scale(*inv, origin=o)
        assert geom_almost_equals(expected, res)

    def test_skew(self):
        expected = self.g4

        skew = 45.0
        o = Point(0, 0)

        # Test xs
        res = self.g4.skew(xs=skew, origin=o).skew(xs=-skew, origin=o)
        assert geom_almost_equals(expected, res)

        res = self.gdf1.set_geometry(self.g4).skew(xs=skew, origin=o)
        res = res.skew(xs=-skew, origin=o)
        assert geom_almost_equals(expected, res)

        # Test ys
        res = self.g4.skew(ys=skew, origin=o).skew(ys=-skew, origin=o)
        assert geom_almost_equals(expected, res)

        res = self.gdf1.set_geometry(self.g4).skew(ys=skew, origin=o)
        res = res.skew(ys=-skew, origin=o)
        assert geom_almost_equals(expected, res)

    def test_buffer(self):
        original = GeoSeries([Point(0, 0)])
        expected = GeoSeries([Polygon(((5, 0), (0, -5), (-5, 0), (0, 5), (5, 0)))])
        calculated = original.buffer(5, resolution=1)
        assert geom_almost_equals(expected, calculated)

    def test_buffer_args(self):
        args = dict(cap_style=3, join_style=2, mitre_limit=2.5)
        calculated_series = self.g0.buffer(10, **args)
        for original, calculated in zip(self.g0, calculated_series):
            if original is None:
                assert calculated is None
            else:
                expected = original.buffer(10, **args)
                assert calculated.equals(expected)

    def test_buffer_distance_array(self):
        original = GeoSeries([self.p0, self.p0])
        expected = GeoSeries(
            [
                Polygon(((6, 5), (5, 4), (4, 5), (5, 6), (6, 5))),
                Polygon(((10, 5), (5, 0), (0, 5), (5, 10), (10, 5))),
            ]
        )
        calculated = original.buffer(np.array([1, 5]), resolution=1)
        assert_geoseries_equal(calculated, expected, check_less_precise=True)

    def test_buffer_distance_wrong_length(self):
        original = GeoSeries([self.p0, self.p0])
        distances = np.array([1, 2, 3])
        with pytest.raises(ValueError):
            original.buffer(distances)

    def test_buffer_distance_wrong_index(self):
        original = GeoSeries([self.p0, self.p0], index=[0, 1])
        distances = Series(data=[1, 2], index=[99, 98])
        with pytest.raises(ValueError):
            original.buffer(distances)

    def test_buffer_empty_none(self):
        p = Polygon([(0, 0), (0, 1), (1, 1), (1, 0)])
        s = GeoSeries([p, GeometryCollection(), None])
        result = s.buffer(0)
        assert_geoseries_equal(result, s)

        result = s.buffer(np.array([0, 0, 0]))
        assert_geoseries_equal(result, s)

    def test_envelope(self):
        e = self.g3.envelope
        assert np.all(e.geom_equals(self.sq))
        assert isinstance(e, GeoSeries)
        assert self.g3.crs == e.crs

    def test_total_bounds(self):
        bbox = self.sol.x, self.sol.y, self.esb.x, self.esb.y
        assert isinstance(self.landmarks.total_bounds, np.ndarray)
        assert tuple(self.landmarks.total_bounds) == bbox

        df = GeoDataFrame(
            {"geometry": self.landmarks, "col1": range(len(self.landmarks))}
        )
        assert tuple(df.total_bounds) == bbox

    def test_explode_geoseries(self):
        s = GeoSeries(
            [MultiPoint([(0, 0), (1, 1)]), MultiPoint([(2, 2), (3, 3), (4, 4)])]
        )
        s.index.name = "test_index_name"
        expected_index_name = ["test_index_name", None]
        index = [(0, 0), (0, 1), (1, 0), (1, 1), (1, 2)]
        expected = GeoSeries(
            [Point(0, 0), Point(1, 1), Point(2, 2), Point(3, 3), Point(4, 4)],
            index=MultiIndex.from_tuples(index, names=expected_index_name),
        )
        assert_geoseries_equal(expected, s.explode())

    @pytest.mark.parametrize("index_name", [None, "test"])
    def test_explode_geodataframe(self, index_name):
        s = GeoSeries([MultiPoint([Point(1, 2), Point(2, 3)]), Point(5, 5)])
        df = GeoDataFrame({"col": [1, 2], "geometry": s})
        df.index.name = index_name

        test_df = df.explode()

        expected_s = GeoSeries([Point(1, 2), Point(2, 3), Point(5, 5)])
        expected_df = GeoDataFrame({"col": [1, 1, 2], "geometry": expected_s})
        expected_index = MultiIndex(
            [[0, 1], [0, 1]],  # levels
            [[0, 0, 1], [0, 1, 0]],  # labels/codes
            names=[index_name, None],
        )
        expected_df = expected_df.set_index(expected_index)
        assert_frame_equal(test_df, expected_df)

    #
    # Test '&', '|', '^', and '-'
    # The left can only be a GeoSeries. The right hand side can be a
    # GeoSeries, GeoDataFrame or Shapely geometry
    #
    def test_intersection_operator(self):
        self._test_binary_operator("__and__", self.t1, self.g1, self.g2)

    def test_union_operator(self):
        self._test_binary_operator("__or__", self.sq, self.g1, self.g2)

    def test_union_operator_polygon(self):
        self._test_binary_operator("__or__", self.sq, self.g1, self.t2)

    def test_symmetric_difference_operator(self):
        self._test_binary_operator("__xor__", self.sq, self.g3, self.g4)

    def test_difference_series2(self):
        expected = GeoSeries([GeometryCollection(), self.t2])
        self._test_binary_operator("__sub__", expected, self.g1, self.g2)

    def test_difference_poly2(self):
        expected = GeoSeries([self.t1, self.t1])
        self._test_binary_operator("__sub__", expected, self.g1, self.t2)