def grid_definition_section(cube, grib):
"""
Set keys within the grid definition section of the provided grib message,
based on the properties of the cube.
"""
x_coord = cube.coord(dimensions=[1])
y_coord = cube.coord(dimensions=[0])
cs = x_coord.coord_system # N.B. already checked same cs for x and y.
regular_x_and_y = is_regular(x_coord) and is_regular(y_coord)
if isinstance(cs, GeogCS):
if not regular_x_and_y:
raise iris.exceptions.TranslationError(
'Saving an irregular latlon grid to GRIB (PDT3.4) is not '
'yet supported.')
grid_definition_template_0(cube, grib)
elif isinstance(cs, RotatedGeogCS):
# Rotated coordinate system cases.
# Choose between GDT 3.1 and 3.5 according to coordinate regularity.
if regular_x_and_y:
grid_definition_template_1(cube, grib)
else:
grid_definition_template_5(cube, grib)
elif isinstance(cs, TransverseMercator):
# Transverse Mercator coordinate system (template 3.12).
grid_definition_template_12(cube, grib)
else:
raise ValueError('Grib saving is not supported for coordinate system: '
'{}'.format(cs))
def grid_definition_section(cube, grib):
"""
Set keys within the grid definition section of the provided grib message,
based on the properties of the cube.
"""
x_coord = cube.coord(dimensions=[1])
y_coord = cube.coord(dimensions=[0])
cs = x_coord.coord_system # N.B. already checked same cs for x and y.
regular_x_and_y = is_regular(x_coord) and is_regular(y_coord)
if isinstance(cs, GeogCS):
if not regular_x_and_y:
raise iris.exceptions.TranslationError(
'Saving an irregular latlon grid to GRIB (PDT3.4) is not '
'yet supported.')
grid_definition_template_0(cube, grib)
elif isinstance(cs, RotatedGeogCS):
# Rotated coordinate system cases.
# Choose between GDT 3.1 and 3.5 according to coordinate regularity.
if regular_x_and_y:
grid_definition_template_1(cube, grib)
else:
grid_definition_template_5(cube, grib)
elif isinstance(cs, TransverseMercator):
# Transverse Mercator coordinate system (template 3.12).
grid_definition_template_12(cube, grib)
else:
raise ValueError('Grib saving is not supported for coordinate system: '
'{}'.format(cs))
def roll_cube_pm180(cube_in, coord_name=UM_LATLON[1], inplace=False):
"""
Take a cube spanning 0...360 degrees in longitude and roll it to -180...180 degrees.
Works with global model output, and in some cases for regional.
Parameters
----------
cube: iris.cube.Cube
Cube with longitude and latitude coordinates.
coord_name: str, optional
Name of the longitude coordinate.
inplace: bool, optional
Do this in-place or copy the cube.
Returns
-------
iris.cube.Cube
See also
--------
aeolus.grid.roll_cube_0_360
"""
if inplace:
cube = cube_in
else:
cube = cube_in.copy()
xcoord = cube.coord(coord_name)
if (xcoord.points >= 0.0).all():
assert is_regular(
xcoord
), "Operation is only valid for a regularly spaced coordinate."
if _is_longitude_global(xcoord.points):
# Shift data symmetrically only when dealing with global cubes
cube.data = np.roll(cube.data, len(xcoord.points) // 2, axis=-1)
if xcoord.has_bounds():
bounds = wrap_lons(xcoord.bounds, -180, 360) # + subtract
bounds = bounds[bounds[:, 0].argsort(axis=0)]
else:
bounds = None
cube.replace_coord(
xcoord.copy(points=np.sort(wrap_lons(xcoord.points, -180, 360)),
bounds=bounds))
else:
# Nothing to do, the cube is already centered on 0 longitude
# unless there is something wrong with longitude
msg = f"Incorrect {coord_name} values: from {xcoord.points.min()} to {xcoord.points.max()}"
assert ((xcoord.points >= -180.0) &
(xcoord.points <= 180.0)).all(), msg
if not inplace:
return cube
def test_save_load(self):
# Load sample UKV data (variable-resolution rotated grid).
path = tests.get_data_path(('PP', 'ukV1', 'ukVpmslont.pp'))
cube = load_cube(path)
# Extract a single 2D field, for simplicity.
self.assertEqual(cube.ndim, 3)
self.assertEqual(cube.coord_dims('time'), (0,))
cube = cube[0]
# FOR NOW: **also** fix the data so that it is square, i.e. nx=ny.
# This is needed because of a bug in the gribapi.
# See : https://software.ecmwf.int/issues/browse/SUP-1096
ny, nx = cube.shape
nn = min(nx, ny)
cube = cube[:nn, :nn]
# Check that it has a rotated-pole variable-spaced grid, as expected.
x_coord = cube.coord(axis='x')
self.assertIsInstance(x_coord.coord_system, RotatedGeogCS)
self.assertFalse(is_regular(x_coord))
# Write to temporary file, check grib_dump output, and load back in.
with self.temp_filename('ukv_sample.grib2') as temp_file_path:
save(cube, temp_file_path)
# Get a grib_dump of the output file.
dump_text = check_output(('grib_dump -O -wcount=1 ' +
temp_file_path),
shell=True).decode()
# Check that various aspects of the saved file are as expected.
expect_strings = (
'editionNumber = 2',
'gridDefinitionTemplateNumber = 5',
'Ni = {:d}'.format(cube.shape[-1]),
'Nj = {:d}'.format(cube.shape[-2]),
'shapeOfTheEarth = 1',
'scaledValueOfRadiusOfSphericalEarth = {:d}'.format(
int(UM_DEFAULT_EARTH_RADIUS)),
'resolutionAndComponentFlags = 0',
'latitudeOfSouthernPole = -37500000',
'longitudeOfSouthernPole = 357500000',
'angleOfRotation = 0')
for expect in expect_strings:
self.assertIn(expect, dump_text)
# Load the Grib file back into a new cube.
with FUTURE.context(strict_grib_load=True):
cube_loaded_from_saved = load_cube(temp_file_path)
# Also load data, before the temporary file gets deleted.
cube_loaded_from_saved.data
# The re-loaded result will not match the original in every respect:
# * cube attributes are discarded
# * horizontal coordinates are rounded to an integer representation
# * bounds on horizontal coords are lost
# Thus the following "equivalence tests" are rather piecemeal..
# Check those re-loaded properties which should match the original.
for test_cube in (cube, cube_loaded_from_saved):
self.assertEqual(test_cube.standard_name,
'air_pressure_at_sea_level')
self.assertEqual(test_cube.units, 'Pa')
self.assertEqual(test_cube.shape, (744, 744))
self.assertEqual(test_cube.cell_methods, ())
# Check no cube attributes on the re-loaded cube.
# Note: this does *not* match the original, but is as expected.
self.assertEqual(cube_loaded_from_saved.attributes, {})
# Now remaining to check: coordinates + data...
# Check they have all the same coordinates.
co_names = [coord.name() for coord in cube.coords()]
co_names_reload = [coord.name()
for coord in cube_loaded_from_saved.coords()]
self.assertEqual(sorted(co_names_reload), sorted(co_names))
# Check all the coordinates.
for coord_name in co_names:
try:
co_orig = cube.coord(coord_name)
co_load = cube_loaded_from_saved.coord(coord_name)
# Check shape.
self.assertEqual(co_load.shape, co_orig.shape,
'Shape of re-loaded "{}" coord is {} '
'instead of {}'.format(coord_name,
co_load.shape,
co_orig.shape))
# Check coordinate points equal, within a tolerance.
self.assertArrayAllClose(co_load.points, co_orig.points,
rtol=1.0e-6)
# Check all coords are unbounded.
# (NOTE: this is not so for the original X and Y coordinates,
# but Grib does not store those bounds).
self.assertIsNone(co_load.bounds)
except AssertionError as err:
self.assertTrue(False,
'Failed on coordinate "{}" : {}'.format(
coord_name, str(err)))
# Check that main data array also matches.
self.assertArrayAllClose(cube.data, cube_loaded_from_saved.data)
def test_save_load(self):
# Load sample UKV data (variable-resolution rotated grid).
path = tests.get_data_path(('PP', 'ukV1', 'ukVpmslont.pp'))
cube = load_cube(path)
# Extract a single 2D field, for simplicity.
self.assertEqual(cube.ndim, 3)
self.assertEqual(cube.coord_dims('time'), (0,))
cube = cube[0]
# FOR NOW: **also** fix the data so that it is square, i.e. nx=ny.
# This is needed because of a bug in the gribapi.
# See : https://software.ecmwf.int/issues/browse/SUP-1096
ny, nx = cube.shape
nn = min(nx, ny)
cube = cube[:nn, :nn]
# Check that it has a rotated-pole variable-spaced grid, as expected.
x_coord = cube.coord(axis='x')
self.assertIsInstance(x_coord.coord_system, RotatedGeogCS)
self.assertFalse(is_regular(x_coord))
# Write to temporary file, check that key contents are in the file,
# then load back in.
with self.temp_filename('ukv_sample.grib2') as temp_file_path:
save(cube, temp_file_path)
# Check that various aspects of the saved file are as expected.
expect_values = (
(0, 'editionNumber', 2),
(3, 'gridDefinitionTemplateNumber', 5),
(3, 'Ni', cube.shape[-1]),
(3, 'Nj', cube.shape[-2]),
(3, 'shapeOfTheEarth', 1),
(3, 'scaledValueOfRadiusOfSphericalEarth',
int(UM_DEFAULT_EARTH_RADIUS)),
(3, 'resolutionAndComponentFlags', 0),
(3, 'latitudeOfSouthernPole', -37500000),
(3, 'longitudeOfSouthernPole', 357500000),
(3, 'angleOfRotation', 0))
self.assertGribMessageContents(temp_file_path, expect_values)
# Load the Grib file back into a new cube.
with FUTURE.context(strict_grib_load=True):
cube_loaded_from_saved = load_cube(temp_file_path)
# Also load data, before the temporary file gets deleted.
cube_loaded_from_saved.data
# The re-loaded result will not match the original in every respect:
# * cube attributes are discarded
# * horizontal coordinates are rounded to an integer representation
# * bounds on horizontal coords are lost
# Thus the following "equivalence tests" are rather piecemeal..
# Check those re-loaded properties which should match the original.
for test_cube in (cube, cube_loaded_from_saved):
self.assertEqual(test_cube.standard_name,
'air_pressure_at_sea_level')
self.assertEqual(test_cube.units, 'Pa')
self.assertEqual(test_cube.shape, (744, 744))
self.assertEqual(test_cube.cell_methods, ())
# Check no cube attributes on the re-loaded cube.
# Note: this does *not* match the original, but is as expected.
self.assertEqual(cube_loaded_from_saved.attributes, {})
# Now remaining to check: coordinates + data...
# Check they have all the same coordinates.
co_names = [coord.name() for coord in cube.coords()]
co_names_reload = [coord.name()
for coord in cube_loaded_from_saved.coords()]
self.assertEqual(sorted(co_names_reload), sorted(co_names))
# Check all the coordinates.
for coord_name in co_names:
try:
co_orig = cube.coord(coord_name)
co_load = cube_loaded_from_saved.coord(coord_name)
# Check shape.
self.assertEqual(co_load.shape, co_orig.shape,
'Shape of re-loaded "{}" coord is {} '
'instead of {}'.format(coord_name,
co_load.shape,
co_orig.shape))
# Check coordinate points equal, within a tolerance.
self.assertArrayAllClose(co_load.points, co_orig.points,
rtol=1.0e-6)
# Check all coords are unbounded.
# (NOTE: this is not so for the original X and Y coordinates,
# but Grib does not store those bounds).
self.assertIsNone(co_load.bounds)
except AssertionError as err:
self.assertTrue(False,
'Failed on coordinate "{}" : {}'.format(
coord_name, str(err)))
# Check that main data array also matches.
self.assertArrayAllClose(cube.data, cube_loaded_from_saved.data)
def _grid_and_pole_rules(cube, pp):
"""
Rules for setting the horizontal grid and pole location of the PP field.
Args:
cube: the cube being saved as a series of PP fields.
pp: the current PP field having save rules applied.
Returns:
The PP field with updated metadata.
"""
lon_coord = vector_coord(cube, 'longitude')
grid_lon_coord = vector_coord(cube, 'grid_longitude')
lat_coord = vector_coord(cube, 'latitude')
grid_lat_coord = vector_coord(cube, 'grid_latitude')
if lon_coord and not is_regular(lon_coord):
pp.bzx = 0
pp.bdx = 0
pp.lbnpt = lon_coord.shape[0]
pp.x = lon_coord.points
elif grid_lon_coord and not is_regular(grid_lon_coord):
pp.bzx = 0
pp.bdx = 0
pp.lbnpt = grid_lon_coord.shape[0]
pp.x = grid_lon_coord.points
elif lon_coord and is_regular(lon_coord):
pp.bzx = lon_coord.points[0] - regular_step(lon_coord)
pp.bdx = regular_step(lon_coord)
pp.lbnpt = len(lon_coord.points)
elif grid_lon_coord and is_regular(grid_lon_coord):
pp.bzx = grid_lon_coord.points[0] - regular_step(grid_lon_coord)
pp.bdx = regular_step(grid_lon_coord)
pp.lbnpt = len(grid_lon_coord.points)
if lat_coord and not is_regular(lat_coord):
pp.bzy = 0
pp.bdy = 0
pp.lbrow = lat_coord.shape[0]
pp.y = lat_coord.points
elif grid_lat_coord and not is_regular(grid_lat_coord):
pp.bzy = 0
pp.bdy = 0
pp.lbrow = grid_lat_coord.shape[0]
pp.y = grid_lat_coord.points
elif lat_coord and is_regular(lat_coord):
pp.bzy = lat_coord.points[0] - regular_step(lat_coord)
pp.bdy = regular_step(lat_coord)
pp.lbrow = len(lat_coord.points)
elif grid_lat_coord and is_regular(grid_lat_coord):
pp.bzy = grid_lat_coord.points[0] - regular_step(grid_lat_coord)
pp.bdy = regular_step(grid_lat_coord)
pp.lbrow = len(grid_lat_coord.points)
# Check if we have a rotated coord system.
if cube.coord_system("RotatedGeogCS") is not None:
pp.lbcode = int(pp.lbcode) + 100
# Check if we have a circular x-coord.
for lon_coord in (lon_coord, grid_lon_coord):
if lon_coord is not None:
if lon_coord.circular:
pp.lbhem = 0
else:
pp.lbhem = 3
return pp
def _grid_and_pole_rules(cube, pp):
"""
Rules for setting the horizontal grid and pole location of the PP field.
Args:
cube: the cube being saved as a series of PP fields.
pp: the current PP field having save rules applied.
Returns:
The PP field with updated metadata.
"""
lon_coord = vector_coord(cube, 'longitude')
grid_lon_coord = vector_coord(cube, 'grid_longitude')
lat_coord = vector_coord(cube, 'latitude')
grid_lat_coord = vector_coord(cube, 'grid_latitude')
if lon_coord and not is_regular(lon_coord):
pp.bzx = 0
pp.bdx = 0
pp.lbnpt = lon_coord.shape[0]
pp.x = lon_coord.points
elif grid_lon_coord and not is_regular(grid_lon_coord):
pp.bzx = 0
pp.bdx = 0
pp.lbnpt = grid_lon_coord.shape[0]
pp.x = grid_lon_coord.points
elif lon_coord and is_regular(lon_coord):
pp.bzx = lon_coord.points[0] - regular_step(lon_coord)
pp.bdx = regular_step(lon_coord)
pp.lbnpt = len(lon_coord.points)
elif grid_lon_coord and is_regular(grid_lon_coord):
pp.bzx = grid_lon_coord.points[0] - regular_step(grid_lon_coord)
pp.bdx = regular_step(grid_lon_coord)
pp.lbnpt = len(grid_lon_coord.points)
if lat_coord and not is_regular(lat_coord):
pp.bzy = 0
pp.bdy = 0
pp.lbrow = lat_coord.shape[0]
pp.y = lat_coord.points
elif grid_lat_coord and not is_regular(grid_lat_coord):
pp.bzy = 0
pp.bdy = 0
pp.lbrow = grid_lat_coord.shape[0]
pp.y = grid_lat_coord.points
elif lat_coord and is_regular(lat_coord):
pp.bzy = lat_coord.points[0] - regular_step(lat_coord)
pp.bdy = regular_step(lat_coord)
pp.lbrow = len(lat_coord.points)
elif grid_lat_coord and is_regular(grid_lat_coord):
pp.bzy = grid_lat_coord.points[0] - regular_step(grid_lat_coord)
pp.bdy = regular_step(grid_lat_coord)
pp.lbrow = len(grid_lat_coord.points)
# Check if we have a rotated coord system.
if cube.coord_system("RotatedGeogCS") is not None:
pp.lbcode = int(pp.lbcode) + 100
# Check if we have a circular x-coord.
for lon_coord in (lon_coord, grid_lon_coord):
if lon_coord is not None:
if lon_coord.circular:
pp.lbhem = 0
else:
pp.lbhem = 3
return pp
def test_scalar_coord(self):
# Check that a `ValueError` is captured.
coord = DimCoord(5)
result = is_regular(coord)
self.assertFalse(result)
def test_coord_with_string_points(self):
# Check that a `TypeError` is captured.
coord = AuxCoord(['a', 'b', 'c'])
result = is_regular(coord)
self.assertFalse(result)
def test_coord_with_regular_step(self):
coord = DimCoord(np.arange(5))
result = is_regular(coord)
self.assertTrue(result)
def test_coord_with_irregular_step(self):
# Check that a `CoordinateNotRegularError` is captured.
coord = AuxCoord(np.array([2, 5, 1, 4]))
result = is_regular(coord)
self.assertFalse(result)
def test_coord_with_string_points(self):
# Check that a `TypeError` is captured.
coord = AuxCoord(['a', 'b', 'c'])
result = is_regular(coord)
self.assertFalse(result)
def test_scalar_coord(self):
# Check that a `ValueError` is captured.
coord = DimCoord(5)
result = is_regular(coord)
self.assertFalse(result)
def test_coord_with_irregular_step(self):
# Check that a `CoordinateNotRegularError` is captured.
coord = AuxCoord(np.array([2, 5, 1, 4]))
result = is_regular(coord)
self.assertFalse(result)
def test_coord_with_regular_step(self):
coord = DimCoord(np.arange(5))
result = is_regular(coord)
self.assertTrue(result)
def test_save_load(self):
# Load sample UKV data (variable-resolution rotated grid).
path = tests.get_data_path(("PP", "ukV1", "ukVpmslont.pp"))
cube = load_cube(path)
# Extract a single 2D field, for simplicity.
self.assertEqual(cube.ndim, 3)
self.assertEqual(cube.coord_dims("time"), (0,))
cube = cube[0]
# Check that it has a rotated-pole variable-spaced grid, as expected.
x_coord = cube.coord(axis="x")
self.assertIsInstance(x_coord.coord_system, RotatedGeogCS)
self.assertFalse(is_regular(x_coord))
# Write to temporary file, check that key contents are in the file,
# then load back in.
with self.temp_filename("ukv_sample.grib2") as temp_file_path:
save(cube, temp_file_path)
# Check that various aspects of the saved file are as expected.
expect_values = (
(0, "editionNumber", 2),
(3, "gridDefinitionTemplateNumber", 5),
(3, "Ni", cube.shape[-1]),
(3, "Nj", cube.shape[-2]),
(3, "shapeOfTheEarth", 1),
(
3,
"scaledValueOfRadiusOfSphericalEarth",
int(UM_DEFAULT_EARTH_RADIUS),
),
(3, "resolutionAndComponentFlags", 0),
(3, "latitudeOfSouthernPole", -37500000),
(3, "longitudeOfSouthernPole", 357500000),
(3, "angleOfRotation", 0),
)
self.assertGribMessageContents(temp_file_path, expect_values)
# Load the Grib file back into a new cube.
cube_loaded_from_saved = load_cube(temp_file_path)
# Also load data, before the temporary file gets deleted.
cube_loaded_from_saved.data
# The re-loaded result will not match the original in every respect:
# * cube attributes are discarded
# * horizontal coordinates are rounded to an integer representation
# * bounds on horizontal coords are lost
# Thus the following "equivalence tests" are rather piecemeal..
# Check those re-loaded properties which should match the original.
for test_cube in (cube, cube_loaded_from_saved):
self.assertEqual(
test_cube.standard_name, "air_pressure_at_sea_level"
)
self.assertEqual(test_cube.units, "Pa")
self.assertEqual(test_cube.shape, (928, 744))
self.assertEqual(test_cube.cell_methods, ())
# Check only the GRIB_PARAM attribute exists on the re-loaded cube.
# Note: this does *not* match the original, but is as expected.
self.assertEqual(
cube_loaded_from_saved.attributes,
{"GRIB_PARAM": GRIBCode("GRIB2:d000c003n001")},
)
# Now remaining to check: coordinates + data...
# Check they have all the same coordinates.
co_names = [coord.name() for coord in cube.coords()]
co_names_reload = [
coord.name() for coord in cube_loaded_from_saved.coords()
]
self.assertEqual(sorted(co_names_reload), sorted(co_names))
# Check all the coordinates.
for coord_name in co_names:
try:
co_orig = cube.coord(coord_name)
co_load = cube_loaded_from_saved.coord(coord_name)
# Check shape.
self.assertEqual(
co_load.shape,
co_orig.shape,
'Shape of re-loaded "{}" coord is {} '
"instead of {}".format(
coord_name, co_load.shape, co_orig.shape
),
)
# Check coordinate points equal, within a tolerance.
self.assertArrayAllClose(
co_load.points, co_orig.points, rtol=1.0e-6
)
# Check all coords are unbounded.
# (NOTE: this is not so for the original X and Y coordinates,
# but Grib does not store those bounds).
self.assertIsNone(co_load.bounds)
except AssertionError as err:
self.assertTrue(
False,
'Failed on coordinate "{}" : {}'.format(
coord_name, str(err)
),
)
# Check that main data array also matches.
self.assertArrayAllClose(cube.data, cube_loaded_from_saved.data)
