fix intersection out of bounds point

SciTools · Mar 10, 2021 · 9862a22 · 9862a22
1 parent 4885e12
commit 9862a22
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Showing 2 changed files with 19 additions and 10 deletions.
diff --git a/lib/iris/cube.py b/lib/iris/cube.py
@@ -3130,18 +3130,19 @@ def _intersect_modulus(
                     pre_wrap_delta != post_wrap_delta
                 )
 
-                # Recalculate the extended minimum.
                 indices = inside_indices[split_cell_indices]
                 cells = bounds[indices]
-                cells_delta = np.diff(coord.bounds[indices])
-
-                # Watch out for ascending/descending bounds
-                if cells_delta[0, 0] > 0:
-                    cells[:, 0] = cells[:, 1] - cells_delta[:, 0]
-                    minimum = np.min(cells[:, 0])
-                else:
-                    cells[:, 1] = cells[:, 0] + cells_delta[:, 0]
-                    minimum = np.min(cells[:, 1])
+                if maximum % modulus not in cells:
+                    # Recalculate the extended minimum.
+                    cells_delta = np.diff(coord.bounds[indices])
+
+                    # Watch out for ascending/descending bounds.
+                    if cells_delta[0, 0] > 0:
+                        cells[:, 0] = cells[:, 1] - cells_delta[:, 0]
+                        minimum = np.min(cells[:, 0])
+                    else:
+                        cells[:, 1] = cells[:, 0] + cells_delta[:, 0]
+                        minimum = np.min(cells[:, 1])
 
             points = wrap_lons(coord.points, minimum, modulus)
 

diff --git a/lib/iris/tests/unit/cube/test_Cube.py b/lib/iris/tests/unit/cube/test_Cube.py
@@ -1731,6 +1731,14 @@ def test_aligned_exclusive(self):
         self.assertEqual(result.data[0, 0, 0], 171)
         self.assertEqual(result.data[0, 0, -1], 189)
 
+    def test_aligned_bounds_at_modulus(self):
+        cube = create_cube(-179.5, 180.5, bounds=True)
+        result = cube.intersection(longitude=(0, 360))
+        self.assertArrayEqual(result.coord("longitude").bounds[0], [0, 1])
+        self.assertArrayEqual(result.coord("longitude").bounds[-1], [359, 360])
+        self.assertEqual(result.data[0, 0, 0], 180)
+        self.assertEqual(result.data[0, 0, -1], 179)
+
     def test_negative_misaligned_points_inside(self):
         cube = create_cube(0, 360, bounds=True)
         result = cube.intersection(longitude=(-10.25, 10.25))