ENH: Expose transform

geopandas/array.py

@@ -1,26 +1,25 @@
+import inspect
 import numbers
 import operator
 import warnings
-import inspect
 from functools import lru_cache
 
 import numpy as np
 import pandas as pd
-from pandas.api.extensions import (
-    ExtensionArray,
-    ExtensionDtype,
-    register_extension_dtype,
-)
-
 import shapely
 import shapely.affinity
 import shapely.geometry
-from shapely.geometry.base import BaseGeometry
 import shapely.ops
 import shapely.wkt
+from pandas.api.extensions import (
+    ExtensionArray,
+    ExtensionDtype,
+    register_extension_dtype,
+)
 from pyproj import CRS, Transformer
 from pyproj.aoi import AreaOfInterest
 from pyproj.database import query_utm_crs_info
+from shapely.geometry.base import BaseGeometry
 
 from .sindex import SpatialIndex
 
@@ -634,6 +633,11 @@ def segmentize(self, max_segment_length):
             crs=self.crs,
         )
 
+    def transform(self, transformation, include_z=False):
+        return GeometryArray(
+            shapely.transform(self._data, transformation, include_z), crs=self.crs
+        )
+
     #
     # Binary predicates
     #

geopandas/base.py

@@ -1,11 +1,11 @@
-from warnings import warn
 import warnings
+from warnings import warn
 
 import numpy as np
 import pandas as pd
-from pandas import DataFrame, Series
 import shapely
-from shapely.geometry import box, MultiPoint
+from pandas import DataFrame, Series
+from shapely.geometry import MultiPoint, box
 from shapely.geometry.base import BaseGeometry
 
 from . import _compat as compat
@@ -1260,6 +1260,45 @@ def segmentize(self, max_segment_length):
         """
         return _delegate_geo_method("segmentize", self, max_segment_length)
 
+    def transform(self, transformation, include_z=False):
+        """Returns a ``GeoSeries`` with the transformation function
+        applied to the geom column coordinates.
+
+        Parameters
+        ----------
+        transformation : Callable
+            A function that transforms a (N, 2) or (N, 3) ndarray of float64
+            to another (N,2) or (N, 3) ndarray of float64
+        include_z : bool, default False
+            If True include the third dimension in the coordinates array that
+            is passed to the transformation function. If a geometry has no third
+            dimension, the z-coordinates passed to the function will be NaN.
+
+        Returns
+        -------
+        GeoSeries
+
+        Examples
+        --------
+        >>> from shapely import Point, Polygon
+        >>> s = geopandas.GeoSeries([Point(0, 0)])
+        >>> s.transform(lambda x: x + 1)
+        0    POINT (1.00000 1.00000)
+        dtype: geometry
+
+        >>> s = geopandas.GeoSeries([Polygon([(0, 0), (1, 1), (0, 1)])])
+        >>> s.transform(lambda x: x * [2, 3])
+        0    POLYGON ((0.00000 0.00000, 2.00000 3.00000, 0.00000 3.00000...
+        dtype: geometry
+
+        By default the third dimension is ignored
+        >>> s = geopandas.GeoSeries([Point(0, 0, 0)])
+        >>> s.transform(lambda x: x + 1, include_z=True)
+        0    POINT Z (1.00000 1.00000 1.00000)
+        dtype: geometry
+        """
+        return _delegate_geo_method("transform", self, transformation, include_z)
+
     #
     # Reduction operations that return a Shapely geometry
     #

geopandas/tests/test_geom_methods.py

@@ -2,31 +2,28 @@
 import warnings
 
 import numpy as np
+import pytest
+import shapely
 from numpy.testing import assert_array_equal
 from pandas import DataFrame, Index, MultiIndex, Series, concat
-
-import shapely
-
+from pandas.testing import assert_frame_equal, assert_index_equal, assert_series_equal
+from shapely import wkt
 from shapely.geometry import (
     LinearRing,
     LineString,
     MultiLineString,
     MultiPoint,
+    MultiPolygon,
     Point,
     Polygon,
-    MultiPolygon,
 )
 from shapely.geometry.collection import GeometryCollection
 from shapely.ops import unary_union
-from shapely import wkt
 
 from geopandas import GeoDataFrame, GeoSeries
 from geopandas.base import GeoPandasBase
-
 from geopandas.testing import assert_geodataframe_equal
 from geopandas.tests.util import assert_geoseries_equal, geom_almost_equals, geom_equals
-from pandas.testing import assert_frame_equal, assert_index_equal, assert_series_equal
-import pytest
 
 
 def assert_array_dtype_equal(a, b, *args, **kwargs):
@@ -915,6 +912,33 @@ def test_segmentize_linestrings(self):
         assert_geoseries_equal(expected_g1, result_g1)
         assert_geoseries_equal(expected_g5, result_g5)
 
+    def test_transform(self):
+        test_2d = GeoSeries(
+            [LineString([(2, 2), (4, 4)]), Polygon([(0, 0), (1, 1), (0, 1)])]
+        )
+        expected_2d = GeoSeries(
+            [LineString([(4, 6), (8, 12)]), Polygon([(0, 0), (2, 3), (0, 3)])]
+        )
+        result_2d = test_2d.transform(lambda x: x * [2, 3])
+        assert_geoseries_equal(expected_2d, result_2d)
+
+        test_3d = GeoSeries(
+            [
+                Point(0, 0, 0),
+                LineString([(2, 2, 2), (4, 4, 4)]),
+                Polygon([(0, 0, 0), (1, 1, 1), (0, 1, 0.5)]),
+            ]
+        )
+        expected_3d = GeoSeries(
+            [
+                Point(1, 1, 1),
+                LineString([(3, 3, 3), (5, 5, 5)]),
+                Polygon([(1, 1, 1), (2, 2, 2), (1, 2, 1.5)]),
+            ]
+        )
+        result_3d = test_3d.transform(lambda x: x + 1, include_z=True)
+        assert_geoseries_equal(expected_3d, result_3d)
+
     def test_concave_hull(self):
         assert_geoseries_equal(self.squares, self.squares.concave_hull())