def fix_bpch2coards(cube, field, filename):
"""
An Iris load callback for properly loading the NetCDF files
created by BPCH2COARDS (GAMAP v2-17+).
"""
global _coordcache2
# units
units = field.units
try:
cube.units = units
except ValueError:
# Try to get equivalent units compatible with udunits.
# Store original unit as cube attribute
conform_units = ctm2cf.get_cfcompliant_units(units)
try:
cube.units = conform_units
except ValueError:
warnings.warn("Invalid udunits2 '{0}'".format(units))
cube.attributes["ctm_units"] = units
# a hack for keeping cube's long_name but show var_name in cube summary
iris.std_names.STD_NAMES[cube.var_name] = {'canonical_units': cube.units}
cube.standard_name = cube.var_name
# attributes
# TODO: don't remove all attributes
cube.attributes.clear()
# longitude coordinate (non strictly monotonic) degrees -> degrees_east
try:
lon = cube.coord('longitude')
lon_dim = cube.coord_dims(lon)[0]
cache_key = 'longitude', filename
if _coordcache2.get(cache_key) is None:
west_ind = np.nonzero(lon.points >= 180.)
lon.points[west_ind] = -1. * (360. - lon.points)
lon.units = 'degrees_east'
_coordcache2[cache_key] = iris.coords.DimCoord.from_coord(lon)
cube.remove_coord(lon)
cube.add_dim_coord(_coordcache2[cache_key], lon_dim)
except iris.exceptions.CoordinateNotFoundError:
pass
# levels coordinate
# 'sigma_level' depreciated in the CF standard (not supported by UDUNITS)
try:
lev = cube.coord('Eta Centers')
lev_dim = cube.coord_dims(lev)[0]
lev_std_name = 'atmosphere_hybrid_sigma_pressure_coordinate'
cache_key = lev_std_name, filename
if _coordcache2.get(cache_key) is None:
lev.standard_name = lev_std_name
lev.units = iris.unit.Unit('1')
d = nc.Dataset(filename)
elev = d.variables['edge'][:]
lev.bounds = np.column_stack((elev[:-1], elev[1:]))
_coordcache2[cache_key] = iris.coords.DimCoord.from_coord(lev)
cube.remove_coord(lev)
cube.add_dim_coord(_coordcache2[cache_key], lev_dim)
except iris.exceptions.CoordinateNotFoundError:
pass
# time: dimension -> scalar coordinate (+ add bounds)
try:
time_coord = cube.coord('time')
time_dim = cube.coord_dims(time_coord)[0]
with iris.FUTURE.context(cell_datetime_objects=True):
tstart = time_coord.cell(0).point
delta_t = time_coord.attributes.pop('delta_t')
tend = tstart + timeutil.strp_relativedelta(delta_t)
time_coord.bounds = [timeutil.time2tau(tstart),
timeutil.time2tau(tend)]
if cube.shape[time_dim] == 1:
slices_dims = [d for d in range(cube.ndim) if d != time_dim]
return cube.slices(slices_dims).next()
except iris.exceptions.CoordinateNotFoundError:
pass
def fix_bpch2nc(cube, field, filename):
"""
An Iris load callback for properly loading the NetCDF files
created by BPCH2NC (GAMAP v2-12+).
"""
global _coordcache
# units
units = field.unit.strip()
try:
cube.units = units
except ValueError:
# Try to get equivalent units compatible with udunits.
# Store original unit as cube attribute
conform_units = ctm2cf.get_cfcompliant_units(units)
try:
cube.units = conform_units
except ValueError:
warnings.warn("Invalid udunits2 '{0}'".format(units))
cube.attributes["ctm_units"] = units
# a hack for keeping cube's long_name but show var_name in cube summary
iris.std_names.STD_NAMES[cube.var_name] = {'canonical_units': cube.units}
cube.standard_name = cube.var_name
# add spatial coordinates
modelname = cube.attributes.get('Model')
res = cube.attributes.get('Delta_Lon'), cube.attributes.get('Delta_Lat')
nlayers = cube.attributes.get('NLayers')
cache_key = modelname, res, nlayers
if _coordcache.get(cache_key) is None:
ctm_grid = grid.CTMGrid.from_model(modelname, resolution=res)
coord_names = ('longitude', 'latitude', 'levels')
lon, lat, lev = irisutil.coord_from_grid(ctm_grid, coord=coord_names)
_coordcache[cache_key] = {'lon': lon, 'lat': lat, 'lev': lev}
if cube.ndim == 3:
cube.add_dim_coord(_coordcache[cache_key]['lon'], 2)
cube.add_dim_coord(_coordcache[cache_key]['lat'], 1)
if cube.shape[0] == nlayers:
cube.add_dim_coord(_coordcache[cache_key]['lev'], 0)
# add time scalar coordinate (get info from global attributes)
tstart = (str(cube.attributes['Start_Date']) +
str(cube.attributes['Start_Time']))
tstart = datetime.datetime.strptime(tstart, "%Y%m%d%H")
tstart = timeutil.time2tau(tstart)
tend = (str(cube.attributes['End_Date']) +
str(cube.attributes['End_Time']))
tend = datetime.datetime.strptime(tend, "%Y%m%d%H")
tend = timeutil.time2tau(tend)
time_coord = iris.coords.DimCoord(points=tstart,
bounds=(tstart, tend),
standard_name='time',
units=irisutil.CTM_TIME_UNIT_IRIS)
cube.add_aux_coord(time_coord)
# attributes
# TODO: don't remove all attributes
cube.attributes.clear()
# handle 2D fields (remove 1-sized 1st dimension)
if cube.ndim == 3 and cube.shape[0] == 1:
#dummy_coord = iris.coords.DimCoord([0], long_name='dummy',
# bounds=[0, 1])
#cube.add_dim_coord(dummy_coord, 0)
return cube.slices(range(1, cube.ndim)).next()