fix Z coord for GeometryCollection

Author: vincentsarago

CHANGELOG.md

@@ -73,6 +73,38 @@ Note: Minor version `0.X.0` update might break the API, It's recommended to pin
     _ = fe.features[0]     # __getitem__
     ```
 
+* make sure `GeometryCollection` are homogeneous for Z coordinates
+
+    ```python
+    from geojson_pydantic.geometries import Point, LineString, GeometryCollection
+    # Before
+    GeometryCollection(
+        type="GeometryCollection",
+        geometries=[
+            Point(type="Point", coordinates=[0, 0]),  # 2D point
+            LineString(
+                type="LineString", coordinates=[(0.0, 0.0, 0.0), (1.0, 1.0, 1.0)]  # 3D LineString
+            ),
+        ],
+    )
+    >>> GeometryCollection(bbox=None, type='GeometryCollection', geometries=[Point(bbox=None, type='Point', coordinates=Position3D(longitude=0.0, latitude=0.0, altitude=0.0)), LineString(bbox=None, type='LineString', coordinates=[Position3D(longitude=0.0, latitude=0.0, altitude=0.0), Position3D(longitude=1.0, latitude=1.0, altitude=1.0)])])
+
+    # Now
+    GeometryCollection(
+        type="GeometryCollection",
+        geometries=[
+            Point(type="Point", coordinates=[0, 0]),  # 2D point
+            LineString(
+                type="LineString", coordinates=[(0.0, 0.0, 0.0), (1.0, 1.0, 1.0)]  # 3D LineString
+            ),
+        ],
+    )
+    >>> ValidationError: 1 validation error for GeometryCollection
+    geometries
+    Value error, GeometryCollection cannot have mixed Z dimensionality. [type=value_error, input_value=[Point(bbox=None, type='P...de=1.0, altitude=1.0)])], input_type=list]
+        For further information visit https://errors.pydantic.dev/2.11/v/value_error
+    ```
+
 ## [1.2.0] - 2024-12-19
 
 * drop python 3.8 support

geojson_pydantic/geometries.py

@@ -278,6 +278,11 @@ def wkt(self) -> str:
         z = " Z " if "Z" in geometries else " "
         return f"{self.type.upper()}{z}{geometries}"
 
+    @property
+    def has_z(self) -> bool:
+        """Checks if any coordinates have a Z value."""
+        return any(geom.has_z for geom in self.geometries)
+
     @field_validator("geometries")
     def check_geometries(cls, geometries: List) -> List:
         """Add warnings for conditions the spec does not explicitly forbid."""
@@ -299,6 +304,9 @@ def check_geometries(cls, geometries: List) -> List:
                 stacklevel=1,
             )
 
+        if len({geom.has_z for geom in geometries}) == 2:
+            raise ValueError("GeometryCollection cannot have mixed Z dimensionality.")
+
         return geometries
 
 

tests/test_geometries.py

@@ -534,12 +534,14 @@ def test_getitem_geometry_collection(coordinates):
 
 def test_wkt_mixed_geometry_collection():
     point = Point(type="Point", coordinates=(0.0, 0.0, 0.0))
-    line_string = LineString(type="LineString", coordinates=[(0.0, 0.0), (1.0, 1.0)])
+    line_string = LineString(
+        type="LineString", coordinates=[(0.0, 0.0, 0.0), (1.0, 1.0, 1.0)]
+    )
     assert (
         GeometryCollection(
             type="GeometryCollection", geometries=[point, line_string]
         ).wkt
-        == "GEOMETRYCOLLECTION Z (POINT Z (0.0 0.0 0.0), LINESTRING (0.0 0.0, 1.0 1.0))"
+        == "GEOMETRYCOLLECTION Z (POINT Z (0.0 0.0 0.0), LINESTRING Z (0.0 0.0 0.0, 1.0 1.0 1.0))"
     )
 
 
@@ -552,6 +554,9 @@ def test_wkt_empty_geometry_collection():
 
 def test_geometry_collection_warnings():
     point = Point(type="Point", coordinates=(0.0, 0.0, 0.0))
+    line_string_z = LineString(
+        type="LineString", coordinates=[(0.0, 0.0, 0.0), (1.0, 1.0, 1.0)]
+    )
     line_string = LineString(type="LineString", coordinates=[(0.0, 0.0), (1.0, 1.0)])
 
     # one geometry
@@ -575,18 +580,15 @@ def test_geometry_collection_warnings():
             type="GeometryCollection",
             geometries=[
                 GeometryCollection(
-                    type="GeometryCollection", geometries=[point, line_string]
+                    type="GeometryCollection", geometries=[point, line_string_z]
                 ),
                 point,
             ],
         )
 
-    # homogeneous geometry
-    with pytest.warns(
-        UserWarning,
-        match="GeometryCollection should not be used for homogeneous collections.",
-    ):
-        GeometryCollection(type="GeometryCollection", geometries=[point, point])
+    # homogeneous (Z) geometry
+    with pytest.raises(ValidationError):
+        GeometryCollection(type="GeometryCollection", geometries=[point, line_string])
 
 
 def test_polygon_from_bounds():
@@ -776,9 +778,9 @@ def test_wkt_empty_geometrycollection():
         "MULTIPOLYGON Z (((0.0 0.0 0.0, 1.0 1.0 0.0, 2.0 2.0 0.0, 3.0 3.0 0.0, 0.0 0.0 0.0)), ((1.0 1.0 0.0, 2.0 2.0 0.0, 3.0 3.0 0.0, 4.0 4.0 0.0, 1.0 1.0 0.0)))",
         "MULTIPOLYGON EMPTY",
         "GEOMETRYCOLLECTION (POINT (0.0 0.0))",
+        "GEOMETRYCOLLECTION (POLYGON EMPTY, MULTIPOLYGON (((0.0 0.0, 1.0 1.0, 2.0 2.0, 3.0 3.0, 0.0 0.0))))",
         "GEOMETRYCOLLECTION (POINT (0.0 0.0), MULTIPOINT ((0.0 0.0), (1.0 1.0)))",
-        "GEOMETRYCOLLECTION Z (POLYGON EMPTY, MULTIPOLYGON Z (((0.0 0.0 0.0, 1.0 1.0 0.0, 2.0 2.0 0.0, 3.0 3.0 0.0, 0.0 0.0 0.0))))",
-        "GEOMETRYCOLLECTION Z (LINESTRING Z (0.0 0.0 0.0, 1.0 1.0 1.0, 2.0 2.0 2.0), MULTILINESTRING ((0.0 0.0, 1.0 1.0), (1.0 1.0, 2.0 2.0)))",
+        "GEOMETRYCOLLECTION Z (POLYGON Z ((0.0 0.0 0.0, 1.0 1.0 0.0, 2.0 2.0 0.0, 3.0 3.0 0.0, 0.0 0.0 0.0)), MULTIPOLYGON Z (((0.0 0.0 0.0, 1.0 1.0 0.0, 2.0 2.0 0.0, 3.0 3.0 0.0, 0.0 0.0 0.0))))",
         "GEOMETRYCOLLECTION EMPTY",
     ),
 )
@@ -843,10 +845,22 @@ def test_geometry_collection_serializer():
             LineString(type="LineString", coordinates=[(0.0, 0.0), (1.0, 1.0)]),
         ],
     )
+    assert not geom.has_z
     # bbox will be in the Dict
     assert "bbox" in geom.model_dump()
     assert "bbox" in geom.model_dump()["geometries"][0]
 
+    geom = GeometryCollection(
+        type="GeometryCollection",
+        geometries=[
+            Point(type="Point", coordinates=[0, 0, 0]),
+            LineString(
+                type="LineString", coordinates=[(0.0, 0.0, 0.0), (1.0, 1.0, 1.0)]
+            ),
+        ],
+    )
+    assert geom.has_z
+
     # bbox should not be in any Geometry nor at the top level
     geom_ser = json.loads(geom.model_dump_json())
     assert "bbox" not in geom_ser