def test_invalid_args():
"""
Test for :func:`esmf_regrid.experimental.unstructured_scheme.regrid_unstructured_to_rectilinear`.
Tests that an appropriate error is raised when arguments are invalid.
"""
n_lons = 6
n_lats = 5
lon_bounds = (-180, 180)
lat_bounds = (-90, 90)
node_src = _gridlike_mesh_cube(n_lons, n_lats, location="node")
edge_src = _gridlike_mesh_cube(n_lons, n_lats, location="edge")
face_src = _gridlike_mesh_cube(n_lons, n_lats, location="face")
tgt = _grid_cube(n_lons, n_lats, lon_bounds, lat_bounds, circular=True)
with pytest.raises(ValueError):
_ = regrid_unstructured_to_rectilinear(tgt, tgt, method="bilinear")
with pytest.raises(ValueError):
_ = regrid_unstructured_to_rectilinear(face_src, tgt, method="other")
with pytest.raises(ValueError) as excinfo:
_ = regrid_unstructured_to_rectilinear(node_src,
tgt,
method="conservative")
expected_message = (
"Conservative regridding requires a source cube located on "
"the face of a cube, target cube had the node location.")
assert expected_message in str(excinfo.value)
with pytest.raises(ValueError) as excinfo:
_ = regrid_unstructured_to_rectilinear(edge_src,
tgt,
method="bilinear")
expected_message = (
"Bilinear regridding requires a source cube with a node "
"or face location, target cube had the edge location.")
assert expected_message in str(excinfo.value)
def test_bilinear():
"""
Basic test for :func:`esmf_regrid.experimental.unstructured_scheme.regrid_unstructured_to_rectilinear`.
Tests with the bilinear method.
"""
n_lons = 6
n_lats = 5
lon_bounds = (-180, 180)
lat_bounds = (-90, 90)
src = _gridlike_mesh_cube(n_lons, n_lats, location="node")
tgt = _grid_cube(n_lons, n_lats, lon_bounds, lat_bounds, circular=True)
# Ensure data in the target grid is different to the expected data.
# i.e. target grid data is all zero, expected data is all one
tgt.data[:] = 0
src = _add_metadata(src)
src.data[:] = 1 # Ensure all data in the source is one.
result = regrid_unstructured_to_rectilinear(src, tgt, method="bilinear")
expected_data = np.ones([n_lats, n_lons])
expected_cube = _add_metadata(tgt)
# Lenient check for data.
assert np.allclose(expected_data, result.data)
# Check metadata and scalar coords.
expected_cube.data = result.data
assert expected_cube == result
def test_resolution():
"""
Basic test for :func:`esmf_regrid.experimental.unstructured_scheme.regrid_unstructured_to_rectilinear`.
Tests the resolution keyword with grids that would otherwise not work.
"""
src = _flat_mesh_cube()
# The resulting grid has full latitude bounds and cells must be split up.
n_lons = 1
n_lats = 5
lon_bounds = (-180, 180)
lat_bounds = (-90, 90)
tgt = _grid_cube(n_lons, n_lats, lon_bounds, lat_bounds)
# Ensure data in the target grid is different to the expected data.
# i.e. target grid data is all zero, expected data is all one
tgt.data[:] = 0
src = _add_metadata(src)
src.data[:] = 1 # Ensure all data in the source is one.
result = regrid_unstructured_to_rectilinear(src, tgt, resolution=8)
expected_data = np.ones([n_lats, n_lons])
expected_cube = _add_metadata(tgt)
# Lenient check for data.
# Note that when resolution=None, this would be a fully masked array.
assert np.allclose(expected_data, result.data)
# Check metadata and scalar coords.
expected_cube.data = result.data
assert expected_cube == result
def test_real_data():
"""
Test for :func:`esmf_regrid.experimental.unstructured_scheme.regrid_unstructured_to_rectilinear`.
Tests with cubes derived from realistic data.
"""
# Load source cube.
test_data_dir = iris.config.TEST_DATA_DIR
src_fn = os.path.join(test_data_dir, "NetCDF", "unstructured_grid",
"lfric_surface_mean.nc")
with PARSE_UGRID_ON_LOAD.context():
src = iris.load_cube(src_fn, "rainfall_flux")
# Load target grid cube.
tgt_fn = os.path.join(test_data_dir, "NetCDF", "global", "xyt",
"SMALL_hires_wind_u_for_ipcc4.nc")
tgt = iris.load_cube(tgt_fn)
# Perform regridding.
result = regrid_unstructured_to_rectilinear(src, tgt)
# Check data.
assert result.shape == (1, 160, 320)
assert np.isclose(result.data.mean(), 2.93844e-5)
assert np.isclose(result.data.std(), 2.71724e-5)
# Check metadata.
assert result.metadata == src.metadata
assert result.coord("time") == src.coord("time")
assert result.coord("latitude") == tgt.coord("latitude")
assert result.coord("longitude") == tgt.coord("longitude")
assert result.coord_dims("time") == (0, )
assert result.coord_dims("latitude") == (1, )
assert result.coord_dims("longitude") == (2, )
def test_multidim_cubes():
"""
Test for :func:`esmf_regrid.experimental.unstructured_scheme.regrid_unstructured_to_rectilinear`.
Tests with multidimensional cubes. The source cube contains
coordinates on the dimensions before and after the mesh dimension.
"""
mesh = _full_mesh()
mesh_length = mesh.connectivity(contains_face=True).shape[0]
h = 2
t = 3
height = DimCoord(np.arange(h), standard_name="height")
time = DimCoord(np.arange(t), standard_name="time")
src_data = np.empty([t, mesh_length, h])
src_data[:] = np.arange(t * h).reshape([t, h])[:, np.newaxis, :]
cube = Cube(src_data)
mesh_coord_x, mesh_coord_y = mesh.to_MeshCoords("face")
cube.add_aux_coord(mesh_coord_x, 1)
cube.add_aux_coord(mesh_coord_y, 1)
cube.add_dim_coord(time, 0)
cube.add_dim_coord(height, 2)
n_lons = 6
n_lats = 5
lon_bounds = (-180, 180)
lat_bounds = (-90, 90)
tgt = _grid_cube(n_lons, n_lats, lon_bounds, lat_bounds, circular=True)
result = regrid_unstructured_to_rectilinear(cube, tgt)
# Lenient check for data.
expected_data = np.empty([t, n_lats, n_lons, h])
expected_data[:] = np.arange(t * h).reshape(t, h)[:, np.newaxis,
np.newaxis, :]
assert np.allclose(expected_data, result.data)
expected_cube = Cube(expected_data)
expected_cube.add_dim_coord(time, 0)
expected_cube.add_dim_coord(tgt.coord("latitude"), 1)
expected_cube.add_dim_coord(tgt.coord("longitude"), 2)
expected_cube.add_dim_coord(height, 3)
# Check metadata and scalar coords.
result.data = expected_data
assert expected_cube == result