fix axis ordering for fiona.transform (#926)

Author: rbuffat

fiona/_transform.pyx

@@ -53,7 +53,6 @@ cdef void *_crs_from_crs(object crs):
             auth, val = init.split(':')
             if auth.upper() == 'EPSG':
                 _crs.OSRImportFromEPSG(osr, int(val))
-                osr_set_traditional_axis_mapping_strategy(osr)
         else:
             crs['wktext'] = True
             for k, v in crs.items():
@@ -66,12 +65,13 @@ cdef void *_crs_from_crs(object crs):
             proj_b = proj.encode('utf-8')
             proj_c = proj_b
             _crs.OSRImportFromProj4(osr, proj_c)
-            osr_set_traditional_axis_mapping_strategy(osr)
     # Fall back for CRS strings like "EPSG:3857."
     else:
         proj_b = crs.encode('utf-8')
         proj_c = proj_b
         _crs.OSRSetFromUserInput(osr, proj_c)
+
+    osr_set_traditional_axis_mapping_strategy(osr)
     return osr
 
 

tests/test_transform.py

@@ -1,9 +1,7 @@
 """Tests of the transform submodule"""
 
 import math
-
 import pytest
-
 from fiona import transform
 
 
@@ -48,3 +46,27 @@
 def test_transform_geom_with_z(geom):
     """Transforming a geom with Z succeeds"""
     g2 = transform.transform_geom("epsg:4326", "epsg:3857", geom, precision=3)
+
+
+@pytest.mark.parametrize("crs", ["epsg:4326",
+                                 "EPSG:4326",
+                                 "WGS84",
+                                 {'init': 'epsg:4326'},
+                                 {'proj': 'longlat', 'datum': 'WGS84', 'no_defs': True},
+                                 "OGC:CRS84"])
+def test_axis_ordering(crs):
+    """ Test if transform uses traditional_axis_mapping """
+
+    expected = (-8427998.647958742, 4587905.27136252)
+    t1 = transform.transform(crs, "epsg:3857", [-75.71], [38.06])
+    assert (t1[0][0], t1[1][0]) == pytest.approx(expected)
+    geom = {"type": "Point", "coordinates": [-75.71, 38.06]}
+    g1 = transform.transform_geom(crs, "epsg:3857", geom, precision=3)
+    assert g1["coordinates"] == pytest.approx(expected)
+
+    rev_expected = (-75.71, 38.06)
+    t2 = transform.transform("epsg:3857", crs, [-8427998.647958742], [4587905.27136252])
+    assert (t2[0][0], t2[1][0]) == pytest.approx(rev_expected)
+    geom = {"type": "Point", "coordinates": [-8427998.647958742, 4587905.27136252]}
+    g2 = transform.transform_geom("epsg:3857", crs, geom, precision=3)
+    assert g2["coordinates"] == pytest.approx(rev_expected)