test_merge.py

import pandas as pd

from shapely.geometry import Point

from geopandas import GeoDataFrame, GeoSeries


class TestMerging:
    def setup_method(self):

        self.gseries = GeoSeries([Point(i, i) for i in range(3)])
        self.series = pd.Series([1, 2, 3])
        self.gdf = GeoDataFrame({"geometry": self.gseries, "values": range(3)})
        self.df = pd.DataFrame({"col1": [1, 2, 3], "col2": [0.1, 0.2, 0.3]})

    def _check_metadata(self, gdf, geometry_column_name="geometry", crs=None):

        assert gdf._geometry_column_name == geometry_column_name
        assert gdf.crs == crs

    def test_merge(self):

        res = self.gdf.merge(self.df, left_on="values", right_on="col1")

        # check result is a GeoDataFrame
        assert isinstance(res, GeoDataFrame)

        # check geometry property gives GeoSeries
        assert isinstance(res.geometry, GeoSeries)

        # check metadata
        self._check_metadata(res)

        # test that crs and other geometry name are preserved
        self.gdf.crs = "epsg:4326"
        self.gdf = self.gdf.rename(columns={"geometry": "points"}).set_geometry(
            "points"
        )
        res = self.gdf.merge(self.df, left_on="values", right_on="col1")
        assert isinstance(res, GeoDataFrame)
        assert isinstance(res.geometry, GeoSeries)
        self._check_metadata(res, "points", self.gdf.crs)

    def test_concat_axis0(self):
        # frame
        res = pd.concat([self.gdf, self.gdf])
        assert res.shape == (6, 2)
        assert isinstance(res, GeoDataFrame)
        assert isinstance(res.geometry, GeoSeries)
        self._check_metadata(res)

        # series
        res = pd.concat([self.gdf.geometry, self.gdf.geometry])
        assert res.shape == (6,)
        assert isinstance(res, GeoSeries)
        assert isinstance(res.geometry, GeoSeries)

    def test_concat_axis1(self):

        res = pd.concat([self.gdf, self.df], axis=1)

        assert res.shape == (3, 4)
        assert isinstance(res, GeoDataFrame)
        assert isinstance(res.geometry, GeoSeries)
        self._check_metadata(res)