update featurecollection crs if overridden by user

src/geodense/lib.py

@@ -235,6 +235,8 @@ def densify_file(  # noqa: PLR0913
             densify_in_projection,
         )
         densify_geojson_object(geojson_obj, config)
+        if src_crs is not None and isinstance(geojson_obj, CrsFeatureCollection):
+            geojson_obj.set_crs_auth_code(src_crs)
         with open(
             output_file_path, "w"
         ) if output_file_path != "-" else sys.stdout as out_f:

tests/data/multipolygon_wrong_crs.json

@@ -0,0 +1,67 @@
+{
+    "type": "FeatureCollection",
+    "name": "polygonen",
+    "crs": {
+        "type": "name",
+        "properties": {
+            "name": "urn:ogc:def:crs:EPSG::4326"
+        }
+    },
+    "features": [
+        {
+            "type": "Feature",
+            "properties": {},
+            "geometry": {
+                "type": "MultiPolygon",
+                "coordinates": [
+                    [
+                        [
+                            [
+                                138871.518881731899455,
+                                597389.993749326560646,
+                                10
+                            ],
+                            [
+                                140036.122569288185332,
+                                592678.040025010588579
+                            ],
+                            [
+                                145468.022542056889506,
+                                593606.184292820515111
+                            ],
+                            [
+                                142646.432552648213459,
+                                597849.345781013718806
+                            ],
+                            [
+                                138871.518881731899455,
+                                597389.993749326560646,
+                                10
+                            ]
+                        ]
+                    ],
+                    [
+                        [
+                            [
+                                266341.966320101171732,
+                                624010.546634015277959
+                            ],
+                            [
+                                259248.56824272783706,
+                                626424.482394860591739
+                            ],
+                            [
+                                261291.278331592533505,
+                                618975.793064830591902
+                            ],
+                            [
+                                266341.966320101171732,
+                                624010.546634015277959
+                            ]
+                        ]
+                    ]
+                ]
+            }
+        }
+    ]
+}

tests/test_densify.py

@@ -1,7 +1,9 @@
+import json
 import os
 import re
 import tempfile
 from contextlib import nullcontext as does_not_raise
+from contextlib import suppress
 
 import pyproj
 import pytest
@@ -221,6 +223,35 @@ def test_densify_file(test_dir):
     assert os.path.exists(out_file)
 
 
+@pytest.mark.parametrize(
+    ("input_file", "src_crs", "expectation"),
+    [
+        (
+            "multipolygon.json",
+            None,
+            "urn:ogc:def:crs:EPSG::28992",
+        ),
+        ("geometry-4326-no-crs.json", None, None),
+        ("geometry-4326-no-crs.json", "OGC:CRS84", None),
+        (
+            "multipolygon_wrong_crs.json",
+            "EPSG:28992",
+            "urn:ogc:def:crs:EPSG::28992",
+        ),
+    ],
+)
+def test_densify_file_crs_matches_input(test_dir, input_file, src_crs, expectation):
+    output_file = os.path.join(tempfile.mkdtemp(), input_file)
+    input_file = os.path.join(test_dir, "data", input_file)
+    densify_file(input_file, output_file, src_crs=src_crs)
+    with open(output_file) as f:
+        geojson = json.load(f)
+        crs = None
+        with suppress(KeyError):
+            crs = geojson["crs"]["properties"]["name"]
+        assert crs == expectation
+
+
 @pytest.mark.parametrize(
     ("input_file", "output_file", "expectation"),
     [