def test_basic_regrid(self):
"""Test default regridding arguments return expected dimensionality
and updated grid-defining attributes"""
expected_data = 282 * np.ones((12, 12), dtype=np.float32)
expected_attributes = {
"mosg__model_configuration": "gl_det",
"title": MANDATORY_ATTRIBUTE_DEFAULTS["title"],
}
for attr in ["mosg__grid_domain", "mosg__grid_type", "mosg__grid_version"]:
expected_attributes[attr] = self.target_grid.attributes[attr]
result = RegridLandSea()(self.cube, self.target_grid.copy())
self.assertArrayAlmostEqual(result.data, expected_data)
for axis in ["x", "y"]:
self.assertEqual(result.coord(axis=axis), self.target_grid.coord(axis=axis))
self.assertDictEqual(result.attributes, expected_attributes)
def test_attribute_changes_with_regridding(self):
"""Test attributes inherited on regridding"""
expected_attributes = self.cube.attributes
expected_attributes["title"] = MANDATORY_ATTRIBUTE_DEFAULTS["title"]
for attr in ["mosg__grid_domain", "mosg__grid_type", "mosg__grid_version"]:
expected_attributes[attr] = self.target_grid.attributes[attr]
result = RegridLandSea()(self.cube, self.target_grid)
self.assertDictEqual(result.attributes, expected_attributes)
def test_new_title(self):
"""Test new title can be set on regridding"""
new_title = "Global Model Forecast on UK 2km Standard Grid"
expected_attributes = self.cube.attributes
expected_attributes["title"] = new_title
for attr in ["mosg__grid_domain", "mosg__grid_type", "mosg__grid_version"]:
expected_attributes[attr] = self.target_grid.attributes[attr]
result = RegridLandSea()(self.cube, self.target_grid, regridded_title=new_title)
self.assertDictEqual(result.attributes, expected_attributes)
def test_error_regrid_with_incorrect_landmask(self):
"""Test an error is thrown if a landmask is provided that does not
match the source grid"""
landmask = self.target_grid.copy()
plugin = RegridLandSea(regrid_mode="nearest-with-mask",
landmask=landmask,
landmask_vicinity=90000)
msg = "Source landmask does not match input grid"
with self.assertRaisesRegex(ValueError, msg):
plugin(self.cube, self.target_grid)
def test_access_regrid_with_landmask(self):
"""Test the AdjustLandSeaPoints module is correctly called when using
landmask arguments. Diagnosed by identifiable error."""
msg = "Distance of 1000m gives zero cell extent"
with self.assertRaisesRegex(ValueError, msg):
RegridLandSea(
regrid_mode="nearest-with-mask",
landmask=self.landmask,
landmask_vicinity=1000,
)(self.cube, self.target_grid)
def test_run_regrid_with_landmask(self):
"""Test masked regridding (same expected values as basic, since input
points are all equal)"""
expected_data = 282 * np.ones((12, 12), dtype=np.float32)
expected_attributes = {
"mosg__model_configuration": "gl_det",
"title": MANDATORY_ATTRIBUTE_DEFAULTS["title"],
}
for attr in ["mosg__grid_domain", "mosg__grid_type", "mosg__grid_version"]:
expected_attributes[attr] = self.target_grid.attributes[attr]
result = RegridLandSea(
regrid_mode="nearest-with-mask",
landmask=self.landmask,
landmask_vicinity=90000,
)(self.cube, self.target_grid.copy())
self.assertArrayAlmostEqual(result.data, expected_data)
for axis in ["x", "y"]:
self.assertEqual(result.coord(axis=axis), self.target_grid.coord(axis=axis))
self.assertDictEqual(result.attributes, expected_attributes)
def test_warning_source_not_landmask(self, warning_list=None):
"""Test warning is raised if landmask_source_grid is not a landmask"""
expected_data = 282 * np.ones((12, 12), dtype=np.float32)
self.landmask.rename("not_a_landmask")
result = RegridLandSea(
regrid_mode="nearest-with-mask",
landmask=self.landmask,
landmask_vicinity=90000,
)(self.cube, self.target_grid)
msg = "Expected land_binary_mask in input_landmask cube"
self.assertTrue(any(msg in str(warning) for warning in warning_list))
self.assertTrue(any(item.category == UserWarning for item in warning_list))
self.assertArrayAlmostEqual(result.data, expected_data)
def process(
cube: cli.inputcube,
target_grid: cli.inputcube,
land_sea_mask: cli.inputcube = None,
*,
regrid_mode="bilinear",
extrapolation_mode="nanmask",
land_sea_mask_vicinity: float = 25000,
regridded_title: str = None,
):
"""Regrids source cube data onto a target grid. Optional land-sea awareness.
Args:
cube (iris.cube.Cube):
Source cube to be regridded.
target_grid (iris.cube.Cube):
Cube defining the spatial grid onto which to regrid the source data.
If also using land_sea_mask-aware regridding then this must be
land_binary_mask data.
land_sea_mask (iris.cube.Cube):
Cube describing the land_binary_mask on the source grid if land-sea
aware regridding is required, with land points set to one and sea points
set to zero.
regrid_mode (str):
Selects which regridding techniques to use. Default uses
iris.analysis.Linear(); "nearest" uses iris.analysis.Nearest();
"nearest-with-mask" uses Nearest() with land-sea awareness.
extrapolation_mode (str):
Mode to use for extrapolating data into regions beyond the limits
of the input cube domain. Refer to online documentation for
iris.analysis.
Modes are -
extrapolate - extrapolated points will take their values from the
nearest source point
nan - extrapolated points will be set to NaN
error - a ValueError will be raised notifying an attempt to
extrapolate
mask - extrapolated points will always be masked, even if
the source data is not a MaskedArray
nanmask - if the source data is a MaskedArray extrapolated points
will be masked; otherwise they will be set to NaN
land_sea_mask_vicinity (float):
Radius of vicinity to search for a coastline, in metres.
regridded_title (str):
New "title" attribute to be set if the field is being regridded
(since "title" may contain grid information). If None, a default
value is used.
Returns:
iris.cube.Cube:
Processed cube.
Raises:
ValueError:
If source land_sea_mask is supplied but regrid mode is not
"nearest-with-mask".
ValueError:
If regrid_mode is "nearest-with-mask" but no source land_sea_mask
is provided (from plugin).
"""
from improver.standardise import RegridLandSea
if land_sea_mask and "nearest-with-mask" not in regrid_mode:
msg = (
"Land-mask file supplied without appropriate regrid-mode. "
"Use --regrid-mode nearest-with-mask."
)
raise ValueError(msg)
return RegridLandSea(
regrid_mode=regrid_mode,
extrapolation_mode=extrapolation_mode,
landmask=land_sea_mask,
landmask_vicinity=land_sea_mask_vicinity,
)(cube, target_grid, regridded_title=regridded_title)
def test_error_missing_landmask(self):
"""Test an error is thrown if no landmask is provided where required"""
msg = "requires an input landmask cube"
with self.assertRaisesRegex(ValueError, msg):
RegridLandSea(regrid_mode="nearest-with-mask")
def test_error_unrecognised_regrid_mode(self):
"""Test error is thrown if regrid mode is not in expected values list"""
msg = "Unrecognised regrid mode"
with self.assertRaisesRegex(ValueError, msg):
RegridLandSea(regrid_mode="kludge")
def test_incorrect_grid_attributes_removed(self):
"""Test grid attributes not present on the target cube are removed
after regridding"""
self.target_grid.attributes.pop("mosg__grid_domain")
result = RegridLandSea()(self.cube, self.target_grid)
self.assertNotIn("mosg__grid_domain", result.attributes)