add exact intersection check (#49)

* add flag to make exact intersection check when selecting tiles from geometry

* also test batch option

* bump version; update changelog

CHANGELOG.rst

@@ -2,6 +2,11 @@
 Changelog
 #########
 
+2022.3.0 - 2022-03-15
+---------------------
+* add option to exactly get intersection tiles using `TilePyramid.tiles_from_geom(exact=True)`
+
+
 2021.11.0 - 2021-11-12
 ----------------------
 * enable yielding tiles in batches by either row or column for following methods:

test/conftest.py

@@ -285,3 +285,15 @@ def multipolygon():
             ],
         }
     )
+
+
+@pytest.fixture
+def tile_bounds_polygon():
+    return shape(
+        {
+            "type": "Polygon",
+            "coordinates": [
+                [(0, 0), (0, 45), (22.5, 45), (22.5, 22.5), (45, 22.5), (45, 0), (0, 0)]
+            ],
+        }
+    )

test/test_tilepyramid.py

@@ -1,7 +1,7 @@
 """TilePyramid creation."""
 
 import pytest
-from shapely.geometry import Point
+from shapely.geometry import Point, box
 from shapely.ops import unary_union
 from types import GeneratorType
 
@@ -323,6 +323,28 @@ def test_tiles_from_bounds_batch_by_row_both_antimeridian_bounds():
     assert tiles == len(list(tp.tiles_from_bounds(bounds, zoom)))
 
 
+def test_tiles_from_geom_exact(tile_bounds_polygon):
+
+    tp = TilePyramid("geodetic")
+    zoom = 3
+
+    tiles = len(list(tp.tiles_from_geom(tile_bounds_polygon, zoom)))
+    assert tiles == 4
+    tiles = 0
+    for batch in tp.tiles_from_geom(tile_bounds_polygon, zoom, batch_by="row"):
+        tiles += len(list(batch))
+    assert tiles == 4
+
+    exact_tiles = len(list(tp.tiles_from_geom(tile_bounds_polygon, zoom, exact=True)))
+    assert exact_tiles == 3
+    tiles = 0
+    for batch in tp.tiles_from_geom(
+        tile_bounds_polygon, zoom, batch_by="row", exact=True
+    ):
+        tiles += len(list(batch))
+    assert tiles == 3
+
+
 def test_snap_bounds():
     bounds = (0, 1, 2, 3)
     tp = TilePyramid("geodetic")

tilematrix/__init__.py

@@ -21,4 +21,4 @@
 ]
 
 
-__version__ = "2021.11.0"
+__version__ = "2022.3.0"

tilematrix/_funcs.py

@@ -1,6 +1,7 @@
 """Helper functions."""
 
-from itertools import product, chain
+from itertools import product
+
 from rasterio.crs import CRS
 from shapely.affinity import translate
 from shapely.geometry import Polygon, GeometryCollection, box

tilematrix/_tilepyramid.py

@@ -185,6 +185,7 @@ def tiles_from_bounds(self, bounds=None, zoom=None, batch_by=None):
         - bounds: tuple of (left, bottom, right, top) bounding values in tile
             pyramid CRS
         - zoom: zoom level
+        - batch_by: yield tiles in row or column batches if activated
         """
         validate_zoom(zoom)
         if not isinstance(bounds, tuple) or len(bounds) != 4:
@@ -208,7 +209,7 @@ def tiles_from_bbox(self, geometry=None, zoom=None, batch_by=None):
         validate_zoom(zoom)
         yield from self.tiles_from_bounds(geometry.bounds, zoom, batch_by=batch_by)
 
-    def tiles_from_geom(self, geometry=None, zoom=None, batch_by=None):
+    def tiles_from_geom(self, geometry=None, zoom=None, batch_by=None, exact=False):
         """
         Return all tiles intersecting with input geometry.
 
@@ -235,18 +236,36 @@ def tiles_from_geom(self, geometry=None, zoom=None, batch_by=None):
             "MultiPolygon",
             "GeometryCollection",
         ):
-            prepared_geometry = prep(clip_geometry_to_srs_bounds(geometry, self))
-            if batch_by:
-                for batch in self.tiles_from_bbox(geometry, zoom, batch_by=batch_by):
-                    yield (
-                        tile
-                        for tile in batch
-                        if prepared_geometry.intersects(tile.bbox())
-                    )
+            if exact:
+                geometry = clip_geometry_to_srs_bounds(geometry, self)
+                if batch_by:
+                    for batch in self.tiles_from_bbox(
+                        geometry, zoom, batch_by=batch_by
+                    ):
+                        yield (
+                            tile
+                            for tile in batch
+                            if geometry.intersection(tile.bbox()).area
+                        )
+                else:
+                    for tile in self.tiles_from_bbox(geometry, zoom, batch_by=batch_by):
+                        if geometry.intersection(tile.bbox()).area:
+                            yield tile
             else:
-                for tile in self.tiles_from_bbox(geometry, zoom, batch_by=batch_by):
-                    if prepared_geometry.intersects(tile.bbox()):
-                        yield tile
+                prepared_geometry = prep(clip_geometry_to_srs_bounds(geometry, self))
+                if batch_by:
+                    for batch in self.tiles_from_bbox(
+                        geometry, zoom, batch_by=batch_by
+                    ):
+                        yield (
+                            tile
+                            for tile in batch
+                            if prepared_geometry.intersects(tile.bbox())
+                        )
+                else:
+                    for tile in self.tiles_from_bbox(geometry, zoom, batch_by=batch_by):
+                        if prepared_geometry.intersects(tile.bbox()):
+                            yield tile
 
     def tile_from_xy(self, x=None, y=None, zoom=None, on_edge_use="rb"):
         """