expose buffer variable (pysal#649)

momepy/functional/_dimension.py

@@ -209,9 +209,9 @@ def longest_axis_length(geometry: GeoDataFrame | GeoSeries) -> Series:
 
 
 def perimeter_wall(
- geometry: GeoDataFrame | GeoSeries, graph: Graph | None = None
+ geometry: GeoDataFrame | GeoSeries, graph: Graph | None = None, buffer: float = 0.01
 ) -> Series:
- """Calculate the perimeter wall length the joined structure.
+ """Calculate the perimeter wall length of the joined structure.
 
  Parameters
  ----------
@@ -220,6 +220,9 @@ def perimeter_wall(
  graph : Graph | None, optional
  Graph encoding Queen contiguity of ``geometry``. If ``None`` Queen contiguity is
  built on the fly.
+ buffer: float
+ Buffer value for the geometry. It can be used
+ to account for topological problems.
 
  Returns
  -------
@@ -276,7 +279,7 @@ def perimeter_wall(
  blocks = geometry.drop(isolates)
  component_perimeter = (
  blocks[[blocks.geometry.name]]
- .set_geometry(blocks.buffer(0.01)) # type: ignore
+ .set_geometry(blocks.buffer(buffer)) # type: ignore
  .dissolve(by=graph.component_labels.drop(isolates))
  .exterior.length
  )

momepy/functional/_intensity.py

@@ -6,7 +6,9 @@
 __all__ = ["courtyards"]
 
 
-def courtyards(geometry: GeoDataFrame | GeoSeries, graph: Graph) -> Series:
+def courtyards(
+ geometry: GeoDataFrame | GeoSeries, graph: Graph, buffer: float = 0.01
+) -> Series:
  """Calculate the number of courtyards within the joined structure.
 
  Adapted from :cite:`schirmer2015`.
@@ -18,6 +20,9 @@ def courtyards(geometry: GeoDataFrame | GeoSeries, graph: Graph) -> Series:
  graph : libpysal.graph.Graph
  A spatial weights matrix for the geodataframe,
  it is used to denote adjacent buildings.
+ buffer: float
+ Buffer value for the geometry. It can be used
+ to account for topological problems.
 
  Returns
  -------
@@ -60,7 +65,7 @@ def courtyards(geometry: GeoDataFrame | GeoSeries, graph: Graph) -> Series:
  def _calculate_courtyards(group):
  """helper function to carry out the per group calculations"""
  return shapely.get_num_interior_rings(
- shapely.union_all(shapely.buffer(group.values, 0.01))
+ shapely.union_all(shapely.buffer(group.values, buffer))
  )
 
  # calculate per group courtyards

momepy/functional/tests/test_dimension.py

@@ -93,6 +93,17 @@ def test_perimeter_wall(self):
  pd.testing.assert_series_equal(result, result_given_graph)
  assert result[0] == pytest.approx(137.210, rel=1e-3)
 
+ def test_perimeter_wall_buffer(self):
+ buildings = self.df_buildings.copy()
+ buildings["geometry"] = buildings.simplify(0.10)
+ adj = Graph.build_contiguity(self.df_buildings)
+ new_perimeter = mm.perimeter_wall(buildings, adj)
+ old_perimeter = mm.perimeter_wall(self.df_buildings, adj)
+ assert (new_perimeter.values != old_perimeter.values).any()
+
+ result = mm.perimeter_wall(buildings, adj, buffer=0.25)
+ assert result[0] == pytest.approx(137.210, rel=1e-3)
+
  @pytest.mark.skipif(not GPD_013, reason="no attribute 'segmentize'")
  def test_street_profile(self):
  sp = mm.street_profile(

momepy/functional/tests/test_intensity.py

@@ -44,6 +44,17 @@ def test_courtyards(self):
  expected = {"mean": 0.6805555555555556, "sum": 98, "min": 0, "max": 1}
  assert_result(courtyards, expected, self.df_buildings)
 
+ def test_courtyards_buffer(self):
+ buildings = self.df_buildings.copy()
+ buildings["geometry"] = buildings.simplify(0.10)
+ new_courtyards = mm.courtyards(buildings, self.buildings_graph)
+ old_courtyards = mm.courtyards(self.df_buildings, self.buildings_graph)
+ assert (new_courtyards.values != old_courtyards.values).any()
+
+ courtyards = mm.courtyards(buildings, self.buildings_graph, buffer=0.25)
+ expected = {"mean": 0.6805555555555556, "sum": 98, "min": 0, "max": 1}
+ assert_result(courtyards, expected, self.df_buildings)
+
  def test_node_density(self):
  g = mm.gdf_to_nx(self.df_streets, integer_labels=True)
  g = mm.node_degree(g)