Merge 39e7217 into 1fc769f

CHANGES.txt

@@ -10,6 +10,8 @@ Shapely 1.8 will support only Python versions >= 3.6.
 
 New features:
 
+- The STRtree nearest*() methods now take an optional argument that
+  specifies exclusion of the input geometry from results (#1115).
 - The STRtree class constructor now takes an optional second argument, a
   sequence of objects to be stored in the tree. If not provided, the sequence
   indices of the geometries will be stored, as before (#1112).

shapely/strtree.py

@@ -21,6 +21,7 @@
 import ctypes
 import logging
 from typing import Any, ItemsView, Iterable, Iterator, Sequence, Tuple, Union
+import sys
 from warnings import warn
 
 from shapely.errors import ShapelyDeprecationWarning
@@ -249,7 +250,9 @@ def query(self, geom: BaseGeometry) -> Sequence[BaseGeometry]:
         """
         return self.query_geoms(geom)
 
-    def nearest_item(self, geom: BaseGeometry) -> Union[Any, None]:
+    def nearest_item(
+        self, geom: BaseGeometry, exclusive: bool = False
+    ) -> Union[Any, None]:
         """Query the tree for the node nearest to geom and get the item
         stored in the node.
 
@@ -259,6 +262,9 @@ def nearest_item(self, geom: BaseGeometry) -> Union[Any, None]:
         ----------
         geom : geometry object
             The query geometry.
+        exclusive : bool, optional
+            Whether to exclude the item corresponding to the given geom
+            from results or not.  Default: False.
 
         Returns
         -------
@@ -289,10 +295,14 @@ def nearest_item(self, geom: BaseGeometry) -> Union[Any, None]:
 
         def callback(item1, item2, distance, userdata):
             try:
+                callback_userdata = ctypes.cast(userdata, ctypes.py_object).value
                 idx = ctypes.cast(item1, ctypes.py_object).value
                 geom2 = ctypes.cast(item2, ctypes.py_object).value
                 dist = ctypes.cast(distance, ctypes.POINTER(ctypes.c_double))
-                lgeos.GEOSDistance(self._rev[idx]._geom, geom2._geom, dist)
+                if callback_userdata["exclusive"] and self._rev[idx].equals(geom2):
+                    dist[0] = sys.float_info.max
+                else:
+                    lgeos.GEOSDistance(self._rev[idx]._geom, geom2._geom, dist)
                 return 1
             except Exception:
                 log.exception("Caught exception")
@@ -303,19 +313,24 @@ def callback(item1, item2, distance, userdata):
             ctypes.py_object(geom),
             envelope._geom,
             lgeos.GEOSDistanceCallback(callback),
-            None,
+            ctypes.py_object({"exclusive": exclusive}),
         )
         result = ctypes.cast(item, ctypes.py_object).value
         return result
 
-    def nearest_geom(self, geom: BaseGeometry) -> Union[BaseGeometry, None]:
+    def nearest_geom(
+        self, geom: BaseGeometry, exclusive: bool = False
+    ) -> Union[BaseGeometry, None]:
         """Query the tree for the node nearest to geom and get the
         geometry corresponding to the item stored in the node.
 
         Parameters
         ----------
         geom : geometry object
             The query geometry.
+        exclusive : bool, optional
+            Whether to exclude the given geom from results or not.
+            Default: False.
 
         Returns
         -------
@@ -325,13 +340,15 @@ def nearest_geom(self, geom: BaseGeometry) -> Union[BaseGeometry, None]:
         version 2.0.
 
         """
-        item = self.nearest_item(geom)
+        item = self.nearest_item(geom, exclusive=exclusive)
         if item is None:
             return None
         else:
             return self._rev[item]
 
-    def nearest(self, geom: BaseGeometry) -> Union[BaseGeometry, None]:
+    def nearest(
+        self, geom: BaseGeometry, exclusive: bool = False
+    ) -> Union[BaseGeometry, None]:
         """Query the tree for the node nearest to geom and get the
         geometry corresponding to the item stored in the node.
 
@@ -342,6 +359,9 @@ def nearest(self, geom: BaseGeometry) -> Union[BaseGeometry, None]:
         ----------
         geom : geometry object
             The query geometry.
+        exclusive : bool, optional
+            Whether to exclude the given geom from results or not.
+            Default: False.
 
         Returns
         -------
@@ -351,4 +371,4 @@ def nearest(self, geom: BaseGeometry) -> Union[BaseGeometry, None]:
         version 2.0.
 
         """
-        return self.nearest_geom(geom)
+        return self.nearest_geom(geom, exclusive=exclusive)

tests/test_strtree.py

@@ -177,3 +177,22 @@ def test_nearest_items(geoms, items):
     with pytest.warns(ShapelyDeprecationWarning):
         tree = STRtree(geoms, items)
     assert tree.nearest_item(None) is None
+
+
+@pytest.mark.skipif(geos_version < (3, 6, 0), reason="GEOS 3.6.0 required")
+@pytest.mark.parametrize(
+    "geoms",
+    [
+        [
+            Point(0, 0.5),
+            Polygon([(1, 0), (2, 0), (2, 1), (1, 1)]),
+            Polygon([(0, 2), (1, 2), (1, 3), (0, 3)]),
+        ]
+    ],
+)
+@pytest.mark.parametrize("items", [list(range(1, 4)), list("abc")])
+@pytest.mark.parametrize("query_geom", [Point(0, 0.5)])
+def test_nearest_item_exclusive(geoms, items, query_geom):
+    with pytest.warns(ShapelyDeprecationWarning):
+        tree = STRtree(geoms, items)
+    assert tree.nearest_item(query_geom, exclusive=True) != items[0]