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"""Module for generating IMPROVER-compliant file names."""
from iris.exceptions import CoordinateNotFoundError
[docs]def generate_file_name(cube, parameter=None):
"""
From a forecast cube, generate an IMPROVER-suitable file name using the
correct lead time. Based on existing StaGE functionality. Requires a
"time" coordinate. If the cube has no "forecast_period" coordinate (for
example if the input is a radar composite or other observation), this
function creates a dummy string representing a forecast period of zero.
Args:
cube (iris.cube.Cube):
Cube containing nowcast data
Kwargs:
parameter (str):
Optional parameter name to use in the output filename rather than
taking the name of the cube diagnostic.
Returns:
filename (str):
File base name to which to write
Raises:
iris.exceptions.CoordinateNotFoundError:
If the input cube has no "time" coordinate
"""
vtime = (cube.coord('time').units).num2date(cube.coord('time').points)[0]
validity_time_string = '{:04}{:02}{:02}T{:02}{:02}Z'.format(
vtime.year, vtime.month, vtime.day, vtime.hour, vtime.minute)
try:
forecast_period_coord = cube.coord('forecast_period').copy()
forecast_period_coord.convert_units('s')
forecast_period, = forecast_period_coord.points
forecast_period_hours = int(forecast_period // 3600)
forecast_period_minutes = int(
(forecast_period - 3600*forecast_period_hours)) // 60
forecast_period_string = 'PT{:04}H{:02}M'.format(
forecast_period_hours, forecast_period_minutes)
except CoordinateNotFoundError:
forecast_period_string = 'PT0000H00M'
if parameter is None:
parameter = cube.name().replace(' ', '_').lower()
for char in ["/", "(", ")"]:
parameter = parameter.replace(char, '')
parameter = parameter.replace('__', '_')
filename = '{}-{}-{}.nc'.format(
validity_time_string, forecast_period_string, parameter)
return filename