def _cube_to_GridInfo(cube, center=False, resolution=None):
# This is a simplified version of an equivalent function/method in PR #26.
# It is anticipated that this function will be replaced by the one in PR #26.
#
# Returns a GridInfo object describing the horizontal grid of the cube.
# This may be inherited from code written for the rectilinear regridding scheme.
lon, lat = cube.coord(axis="x"), cube.coord(axis="y")
# Checks may cover units, coord systems (e.g. rotated pole), contiguous bounds.
if cube.coord_system() is None:
crs = None
else:
crs = cube.coord_system().as_cartopy_crs()
londim, latdim = len(lon.shape), len(lat.shape)
assert londim == latdim
assert londim in (1, 2)
if londim == 1:
# Ensure coords come from a proper grid.
assert isinstance(lon, iris.coords.DimCoord)
assert isinstance(lat, iris.coords.DimCoord)
circular = lon.circular
# TODO: perform checks on lat/lon.
elif londim == 2:
assert cube.coord_dims(lon) == cube.coord_dims(lat)
assert lon.is_contiguous()
assert lat.is_contiguous()
# 2D coords must be AuxCoords, which do not have a circular attribute.
circular = False
lon_bound_array = lon.contiguous_bounds()
lon_bound_array = lon.units.convert(lon_bound_array, Unit("degrees"))
lat_bound_array = lat.contiguous_bounds()
lat_bound_array = lat.units.convert(lat_bound_array, Unit("degrees"))
if resolution is None:
grid_info = GridInfo(
lon.points,
lat.points,
lon_bound_array,
lat_bound_array,
crs=crs,
circular=circular,
center=center,
)
else:
grid_info = RefinedGridInfo(
lon_bound_array,
lat_bound_array,
crs=crs,
resolution=resolution,
)
return grid_info
def _create_cf_grid_mapping(dataset, cube, cf_var):
"""
Create CF-netCDF grid mapping variable and associated CF-netCDF
data variable grid mapping attribute.
"""
cs = cube.coord_system('HorizontalCS')
if cs is not None:
if isinstance(cs, iris.coord_systems.LatLonCS):
cf_grid_name = 'rotated_latitude_longitude' if cs.has_rotated_pole() else 'latitude_longitude'
if cf_grid_name not in dataset.variables:
cf_var.grid_mapping = cf_grid_name
cf_var_grid = dataset.createVariable(cf_grid_name, np.int32)
cf_var_grid.grid_mapping_name = cf_grid_name
cf_var_grid.longitude_of_prime_meridian = 0.0
if cs.datum:
cf_var_grid.semi_major_axis = cs.datum.semi_major_axis
cf_var_grid.semi_minor_axis = cs.datum.semi_minor_axis
if cs.has_rotated_pole():
if cs.n_pole:
cf_var_grid.grid_north_pole_latitude = cs.n_pole.latitude
cf_var_grid.grid_north_pole_longitude = cs.n_pole.longitude
cf_var_grid.north_pole_grid_longitude = cs.reference_longitude
else:
# Reference previously created grid mapping
cf_var.grid_mapping = cf_grid_name
else:
warnings.warn('Unable to represent the horizontal coordinate system. The coordinate system type %r is not yet implemented.' % type(cs))
def _map_common(draw_method_name, arg_func, mode, cube, data, *args, **kwargs):
"""
Draw the given cube on a map using its points or bounds.
"Mode" parameter will switch functionality between POINT or BOUND plotting.
"""
# get the 2d x and 2d y from the CS
if mode == iris.coords.POINT_MODE:
x, y = cartography.get_xy_grids(cube)
else:
try:
x, y = cartography.get_xy_contiguous_bounded_grids(cube)
# Exception translation.
except iris.exceptions.CoordinateMultiDimError:
raise ValueError("Could not get XY grid from bounds. "
"X or Y coordinate not 1D.")
except ValueError:
raise ValueError("Could not get XY grid from bounds. "
"X or Y coordinate doesn't have 2 bounds "
"per point.")
# take a copy of the data so that we can make modifications to it
data = data.copy()
# If we are global, then append the first column of data the array to the
# last (and add 360 degrees) NOTE: if it is found that this block of code
# is useful in anywhere other than this plotting routine, it may be better
# placed in the CS.
x_coord = cube.coord(axis="X")
if getattr(x_coord, 'circular', False):
_, direction = iris.util.monotonic(x_coord.points,
return_direction=True)
y = np.append(y, y[:, 0:1], axis=1)
x = np.append(x, x[:, 0:1] + 360 * direction, axis=1)
data = ma.concatenate([data, data[:, 0:1]], axis=1)
# Replace non-cartopy subplot/axes with a cartopy alternative.
cs = cube.coord_system('CoordSystem')
if cs:
cartopy_proj = cs.as_cartopy_projection()
else:
cartopy_proj = cartopy.crs.PlateCarree()
ax = _get_cartopy_axes(cartopy_proj)
draw_method = getattr(ax, draw_method_name)
# Set the "from transform" keyword.
# NB. While cartopy doesn't support spherical contours, just use the
# projection as the source CRS.
assert 'transform' not in kwargs, 'Transform keyword is not allowed.'
kwargs['transform'] = cartopy_proj
if arg_func is not None:
new_args, kwargs = arg_func(x, y, data, *args, **kwargs)
else:
new_args = (x, y, data) + args
# Draw the contour lines/filled contours.
return draw_method(*new_args, **kwargs)
def _check_both_conversions(self, cube):
lats, lons = iris.analysis.cartography.get_lat_lon_grids(cube)
plt.scatter(lons, lats)
self.check_graphic()
n_pole = cube.coord_system('LatLonCS').n_pole
rlons, rlats = iris.analysis.cartography.rotate_pole(lons, lats, n_pole.longitude, n_pole.latitude)
plt.scatter(rlons, rlats)
self.check_graphic()
def _check_both_conversions(self, cube):
rlons, rlats = iris.analysis.cartography.get_xy_grids(cube)
rcs = cube.coord_system('RotatedGeogCS')
x, y = iris.analysis.cartography.unrotate_pole(
rlons, rlats, rcs.grid_north_pole_longitude,
rcs.grid_north_pole_latitude)
plt.scatter(x, y)
self.check_graphic()
plt.scatter(rlons, rlats)
self.check_graphic()
def _check_both_conversions(self, cube):
rlons, rlats = iris.analysis.cartography.get_xy_grids(cube)
rcs = cube.coord_system('RotatedGeogCS')
x, y = iris.analysis.cartography.unrotate_pole(
rlons, rlats, rcs.grid_north_pole_longitude,
rcs.grid_north_pole_latitude)
plt.scatter(x, y)
self.check_graphic()
plt.scatter(rlons, rlats)
self.check_graphic()
def default_projection(cube):
"""
Return the primary map projection for the given cube.
Using the returned projection, one can create a cartopy map with::
import matplotlib.pyplot as plt
ax = plt.ax(projection=default_projection(cube))
"""
# XXX logic seems flawed, but it is what map_setup did...
cs = cube.coord_system("CoordSystem")
projection = cs.as_cartopy_projection() if cs else None
return projection
def default_projection(cube):
"""
Return the primary map projection for the given cube.
Using the returned projection, one can create a cartopy map with::
import matplotlib.pyplot as plt
ax = plt.ax(projection=default_projection(cube))
"""
# XXX logic seems flawed, but it is what map_setup did...
cs = cube.coord_system("CoordSystem")
projection = cs.as_cartopy_projection() if cs else None
return projection
def _check_both_conversions(self, cube, index):
rlons, rlats = iris.analysis.cartography.get_xy_grids(cube)
rcs = cube.coord_system('RotatedGeogCS')
x, y = iris.analysis.cartography.unrotate_pole(
rlons, rlats, rcs.grid_north_pole_longitude,
rcs.grid_north_pole_latitude)
self.assertDataAlmostEqual(
x, ('analysis', 'rotated_pole.{}.x.json'.format(index)))
self.assertDataAlmostEqual(
y, ('analysis', 'rotated_pole.{}.y.json'.format(index)))
self.assertDataAlmostEqual(
rlons, ('analysis', 'rotated_pole.{}.rlon.json'.format(index)))
self.assertDataAlmostEqual(
rlats, ('analysis', 'rotated_pole.{}.rlat.json'.format(index)))
def _check_both_conversions(self, cube, index):
rlons, rlats = iris.analysis.cartography.get_xy_grids(cube)
rcs = cube.coord_system('RotatedGeogCS')
x, y = iris.analysis.cartography.unrotate_pole(
rlons, rlats, rcs.grid_north_pole_longitude,
rcs.grid_north_pole_latitude)
self.assertDataAlmostEqual(x, ('analysis',
'rotated_pole.{}.x.json'.format(index)))
self.assertDataAlmostEqual(y, ('analysis',
'rotated_pole.{}.y.json'.format(index)))
self.assertDataAlmostEqual(rlons,
('analysis',
'rotated_pole.{}.rlon.json'.format(index)))
self.assertDataAlmostEqual(rlats,
('analysis',
'rotated_pole.{}.rlat.json'.format(index)))
def _create_cf_grid_mapping(dataset, cube, cf_var):
"""
Create CF-netCDF grid mapping variable and associated CF-netCDF
data variable grid mapping attribute.
"""
# TODO: What if there's more than one CoordSystem?
cs = cube.coord_system('CoordSystem')
if cs is not None:
# Grid var not yet created?
if cs.grid_mapping_name not in dataset.variables:
cf_var_grid = dataset.createVariable(cs.grid_mapping_name, np.int32)
cf_var_grid.grid_mapping_name = cs.grid_mapping_name
# latlon
if isinstance(cs, iris.coord_systems.GeogCS):
cf_var_grid.longitude_of_prime_meridian = cs.longitude_of_prime_meridian
cf_var_grid.semi_major_axis = cs.semi_major_axis
cf_var_grid.semi_minor_axis = cs.semi_minor_axis
# rotated latlon
elif isinstance(cs, iris.coord_systems.RotatedGeogCS):
if cs.ellipsoid:
cf_var_grid.longitude_of_prime_meridian = cs.ellipsoid.longitude_of_prime_meridian
cf_var_grid.semi_major_axis = cs.ellipsoid.semi_major_axis
cf_var_grid.semi_minor_axis = cs.ellipsoid.semi_minor_axis
cf_var_grid.grid_north_pole_latitude = cs.grid_north_pole_latitude
cf_var_grid.grid_north_pole_longitude = cs.grid_north_pole_longitude
cf_var_grid.north_pole_grid_longitude = cs.north_pole_grid_longitude
# tmerc
elif isinstance(cs, iris.coord_systems.TransverseMercator):
warnings.warn('TransverseMercator coordinate system not yet handled')
# osgb (a specific tmerc)
elif isinstance(cs, iris.coord_systems.OSGB):
warnings.warn('OSGB coordinate system not yet handled')
# other
else:
warnings.warn('Unable to represent the horizontal coordinate system. The coordinate system type %r is not yet implemented.' % type(cs))
# Refer to grid var
cf_var.grid_mapping = cs.grid_mapping_name
def _create_cf_grid_mapping(self, cube, cf_var_cube):
"""
Create CF-netCDF grid mapping variable and associated CF-netCDF
data variable grid mapping attribute.
Args:
* cube (:class:`iris.cube.Cube`) or cubelist
(:class:`iris.cube.CubeList`):
A :class:`iris.cube.Cube`, :class:`iris.cube.CubeList` or list of
cubes to be saved to a netCDF file.
* cf_var_cube (:class:`netcdf.netcdf_variable`):
cf variable cube representation.
Returns:
None
"""
cs = cube.coord_system('CoordSystem')
if cs is not None:
# Grid var not yet created?
if cs not in self._coord_systems:
while cs.grid_mapping_name in self._dataset.variables:
cs.grid_mapping_name = (
self._increment_name(cs.grid_mapping_name))
cf_var_grid = self._dataset.createVariable(
cs.grid_mapping_name, np.int32)
cf_var_grid.grid_mapping_name = cs.grid_mapping_name
# latlon
if isinstance(cs, iris.coord_systems.GeogCS):
cf_var_grid.longitude_of_prime_meridian = (
cs.longitude_of_prime_meridian)
cf_var_grid.semi_major_axis = cs.semi_major_axis
cf_var_grid.semi_minor_axis = cs.semi_minor_axis
# rotated latlon
elif isinstance(cs, iris.coord_systems.RotatedGeogCS):
if cs.ellipsoid:
cf_var_grid.longitude_of_prime_meridian = (
cs.ellipsoid.longitude_of_prime_meridian)
cf_var_grid.semi_major_axis = (
cs.ellipsoid.semi_major_axis)
cf_var_grid.semi_minor_axis = (
cs.ellipsoid.semi_minor_axis)
cf_var_grid.grid_north_pole_latitude = (
cs.grid_north_pole_latitude)
cf_var_grid.grid_north_pole_longitude = (
cs.grid_north_pole_longitude)
cf_var_grid.north_pole_grid_longitude = (
cs.north_pole_grid_longitude)
# tmerc
elif isinstance(cs, iris.coord_systems.TransverseMercator):
warnings.warn('TransverseMercator coordinate system not '
'yet handled')
# osgb (a specific tmerc)
elif isinstance(cs, iris.coord_systems.OSGB):
warnings.warn('OSGB coordinate system not yet handled')
# other
else:
warnings.warn('Unable to represent the horizontal '
'coordinate system. The coordinate system '
'type %r is not yet implemented.' % type(cs))
self._coord_systems.append(cs)
# Refer to grid var
cf_var_cube.grid_mapping = cs.grid_mapping_name
def _create_cf_grid_mapping(self, cube, cf_var_cube):
"""
Create CF-netCDF grid mapping variable and associated CF-netCDF
data variable grid mapping attribute.
Args:
* cube (:class:`iris.cube.Cube`) or cubelist
(:class:`iris.cube.CubeList`):
A :class:`iris.cube.Cube`, :class:`iris.cube.CubeList` or list of
cubes to be saved to a netCDF file.
* cf_var_cube (:class:`netcdf.netcdf_variable`):
cf variable cube representation.
Returns:
None
"""
cs = cube.coord_system('CoordSystem')
if cs is not None:
# Grid var not yet created?
if cs not in self._coord_systems:
while cs.grid_mapping_name in self._dataset.variables:
cs.grid_mapping_name = (
self._increment_name(cs.grid_mapping_name))
cf_var_grid = self._dataset.createVariable(
cs.grid_mapping_name, np.int32)
cf_var_grid.grid_mapping_name = cs.grid_mapping_name
# latlon
if isinstance(cs, iris.coord_systems.GeogCS):
cf_var_grid.longitude_of_prime_meridian = (
cs.longitude_of_prime_meridian)
cf_var_grid.semi_major_axis = cs.semi_major_axis
cf_var_grid.semi_minor_axis = cs.semi_minor_axis
# rotated latlon
elif isinstance(cs, iris.coord_systems.RotatedGeogCS):
if cs.ellipsoid:
cf_var_grid.longitude_of_prime_meridian = (
cs.ellipsoid.longitude_of_prime_meridian)
cf_var_grid.semi_major_axis = (
cs.ellipsoid.semi_major_axis)
cf_var_grid.semi_minor_axis = (
cs.ellipsoid.semi_minor_axis)
cf_var_grid.grid_north_pole_latitude = (
cs.grid_north_pole_latitude)
cf_var_grid.grid_north_pole_longitude = (
cs.grid_north_pole_longitude)
cf_var_grid.north_pole_grid_longitude = (
cs.north_pole_grid_longitude)
# tmerc
elif isinstance(cs, iris.coord_systems.TransverseMercator):
warnings.warn('TransverseMercator coordinate system not '
'yet handled')
# osgb (a specific tmerc)
elif isinstance(cs, iris.coord_systems.OSGB):
warnings.warn('OSGB coordinate system not yet handled')
# other
else:
warnings.warn('Unable to represent the horizontal '
'coordinate system. The coordinate system '
'type %r is not yet implemented.' % type(cs))
self._coord_systems.append(cs)
# Refer to grid var
cf_var_cube.grid_mapping = cs.grid_mapping_name