Padding while cropping needs to stay within sane bounds for shapefiles that span the whole Earth

esmvalcore/preprocessor/_area.py

@@ -331,14 +331,21 @@ def _crop_cube(cube, start_longitude, start_latitude, end_longitude,
         lon_bound = lon_coord.core_bounds()[0]
         lon_step = lon_bound[1] - lon_bound[0]
         start_longitude -= lon_step
+        if start_longitude < 0:
+            start_longitude = 0
         end_longitude += lon_step
+        if end_longitude > 360:
+            end_longitude = 360.
         lat_bound = lat_coord.core_bounds()[0]
         lat_step = lat_bound[1] - lat_bound[0]
         start_latitude -= lat_step
+        if start_latitude < -90:
+            start_latitude = -90.
         end_latitude += lat_step
+        if end_latitude > 90.:
+            end_latitude = 90.
         cube = extract_region(cube, start_longitude, end_longitude,
                               start_latitude, end_latitude)
-
     return cube
 
 

tests/unit/preprocessor/_area/test_area.py

@@ -7,6 +7,7 @@
 import numpy as np
 import pytest
 from cf_units import Unit
+from iris.cube import Cube
 from shapely.geometry import Polygon, mapping
 
 import tests
@@ -377,6 +378,40 @@ def square_composite_shape(request, tmp_path):
     return np.ma.masked_array(vals, mask)
 
 
+def _create_sample_full_cube():
+    cube = Cube(np.zeros((4, 180, 360)), var_name='co2', units='J')
+    cube.add_dim_coord(
+        iris.coords.DimCoord(
+            np.array([10., 40., 70., 110.]),
+            standard_name='time',
+            units=Unit('days since 1950-01-01 00:00:00', calendar='gregorian'),
+        ),
+        0,
+    )
+    cube.add_dim_coord(
+        iris.coords.DimCoord(
+            np.arange(-90., 90., 1.),
+            standard_name='latitude',
+            units='degrees',
+        ),
+        1,
+    )
+    cube.add_dim_coord(
+        iris.coords.DimCoord(
+            np.arange(0., 360., 1.),
+            standard_name='longitude',
+            units='degrees',
+        ),
+        2,
+    )
+
+    cube.coord("time").guess_bounds()
+    cube.coord("longitude").guess_bounds()
+    cube.coord("latitude").guess_bounds()
+
+    return cube
+
+
 def test_crop_cube(make_testcube, square_shape, tmp_path):
     """Test for cropping a cube by shape bounds."""
     with fiona.open(tmp_path / 'test_shape.shp') as geometries:
@@ -385,6 +420,22 @@ def test_crop_cube(make_testcube, square_shape, tmp_path):
         np.testing.assert_array_equal(result.data, expected)
 
 
+def test_crop_cube_with_ne_file():
+    """Test for cropping a cube by shape bounds."""
+    shp_file = "esmvalcore/preprocessor/ne_masks/ne_50m_ocean.shp"
+    with fiona.open(shp_file) as geometries:
+        cube = _create_sample_full_cube()
+        copy_bounds = list(geometries.bounds)
+        copy_bounds[2] = 370.
+        copy_bounds[1] = -99.
+        copy_bounds[3] = 100.
+        result = _crop_cube(cube, *tuple(copy_bounds))
+        result = (result.coord("latitude").points[-1],
+                  result.coord("longitude").points[-1])
+        expected = (89., 359.)
+        np.testing.assert_allclose(result, expected)
+
+
 @pytest.mark.parametrize('crop', [True, False])
 def test_extract_shape(make_testcube, square_shape, tmp_path, crop):
     """Test for extracting a region with shapefile"""