Make sure that 2D CRS's are promoted to 3D

This ensures that transformations with heigths are performed correctly.
Otherwise, in some cases, the vertical component will be disregarded due
to not automatically being promoted to 3D CRS's.

A test has been added to hopefully avoid this situation in the future.

tests/test_api.py

@@ -55,8 +55,8 @@ def _assert_coordinate(entry, expected_json_output, tolerance=1e-6):
     client = TestClient(app)
     response = client.get(entry)
     result = response.json()
-    print(expected_json_output)
-    print(result)
+    print("expected_output:", expected_json_output)
+    print("results        :", result)
     for key in expected_json_output.keys():
         if key not in result.keys():
             raise AssertionError
@@ -316,6 +316,20 @@ def test_combined_epsg_codes(api_all):
     }
     _assert_coordinate(api_entry, expected, tolerance=0.01)
 
+def test_conversion_to_3d(api_all):
+    """
+    Test that a 2D CRS is correctly promoted to 3D when used in
+    combination with a 3D CRS.
+
+    """
+    api_entry = f"/{api_all}/trans/EPSG:4258/EPSG:4258+5799/55.5,11.5,0"
+    expected = {
+        "v1": 55.5,
+        "v2": 11.5,
+        "v3": -37.4190,
+        "v4": None,
+    }
+    _assert_coordinate(api_entry, expected, tolerance=0.01)
 
 def test_crs_return_srid(api_from_v1_1):
     """

webproj/api.py

@@ -14,11 +14,11 @@
 from fastapi.middleware.cors import CORSMiddleware
 from pydantic import BaseModel
 import pyproj
-from pyproj.transformer import Transformer, AreaOfInterest
+from pyproj.transformer import Transformer, AreaOfInterest, CRS
 
 from webproj.middleware import ProxyHeaderMiddleware
 
-__VERSION__ = "1.2.3"
+__VERSION__ = "1.2.4"
 
 if "WEBPROJ_LIB" in os.environ:
     pyproj.datadir.append_data_dir(os.environ["WEBPROJ_LIB"])
@@ -182,8 +182,13 @@ def __init__(self, src, dst):
                 dst_hub = "EPSG:4909"
 
             try:
+                # Explicit promotion to 3D CRS's to ensure vertical
+                # transformations are picked up correctly.
+                # Tested in test_conversion_to_3d().
                 self.epsg_pipeline = Transformer.from_crs(
-                    src, dst_hub, area_of_interest=region
+                    crs_from=CRS(src).to_3d(),
+                    crs_to=CRS(dst_hub).to_3d(),
+                    area_of_interest=region,
                 )
             except RuntimeError as error:
                 raise ValueError("Invalid CRS identifier") from error