def test_mean_datetime(input_, output):
x = [ parse(t).replace(tzinfo=utc) for t in input_ ]
assert mean_datetime(x) == parse(output).replace(tzinfo=utc)
def test_mean_datetime(input_, output):
x = [parse(t).replace(tzinfo=utc) for t in input_]
assert mean_datetime(x) == parse(output).replace(tzinfo=utc)
def stats(
sesh,
id_,
time,
area,
variable,
is_thredds=False,
):
"""Request and calculate summary statistics averaged across a region
For performing regional analysis, one typically wants to summarize
statistical information across a region. This call allows one to
request either a single timestep (or an average across all
timesteps), and averaged across all cells within the given region.
The stats call may only be called for a single data file and single
variable per invocation.
Args:
sesh (sqlalchemy.orm.session.Session): A database Session object
id_ (str): Unique id which is a key to the data file requested
time (int): Timestep index (0-based) representing the time of year;
0-11 for monthly, 0-3 for seasonal, 0 for annual datasets.
area (str): WKT polygon of selected area
variable (str): Short name of the variable to be returned
is_thredds (bool): If set to `True` the filepath will be searched for
on THREDDS server. This flag is not needed when running the backend
as a server as the files are accessed over the web.
Returns:
dict: Empty dictionary if model_id is not found in the database.
Otherwise, returns a single dict with the key of the file's
unique_id and the value consisting of a nested dictionary with
the following attributes: 'mean', 'stdev', 'min', 'max',
'median', 'ncells', 'units', 'time'.
For example ::
{'file0':
{
'mean': 303.97227647569446,
'stdev': 8.428096450998078,
'min': 288.71807861328125,
'max': 318.9695739746094,
'median': 301.61065673828125,
'ncells': 72,
'units': 'K',
'time': datetime.datetime(1985, 6, 30, 12, 0, 0),
'modtime': datetime.datetime(2010, 1, 1, 17, 30, 4)
}
}
There are two semi-error cases which should be mentioned, when
the filesystem is out of sync with the database.
1. The file pointed to by `id_` does not exist in the filesystem
2. The requested variable does not exist in the given file
In these cases, the numerical values will all be NaN, and the
results dict will be missing the 'units' and 'time' keys.
Raises:
Exception: If `time` parameter cannot be converted to an integer
"""
# Validate arguments
if time:
try:
time = int(time)
except ValueError:
raise Exception(
'time parameter "{}" not convertable to an integer.'.format(
time))
else:
time = None
if isinstance(is_thredds, str):
is_thredds = strtobool(is_thredds)
try:
df = sesh.query(DataFile).filter(DataFile.unique_id == id_).one()
resource = df.filename if not is_thredds else apply_thredds_root(
df.filename)
except NoResultFound:
return {}
try:
with open_nc(resource) as nc:
array = get_array(nc, resource, time, area, variable)
units = get_units_from_netcdf_file(nc, variable)
except Exception as e:
log.error(e)
return {id_: na_array_stats}
stats = array_stats(array)
query = sesh.query(Time.timestep).filter(Time.time_set_id == df.timeset.id)
if time:
query.filter(Time.time_idx == time)
timevals = [t for t, in query.all()]
timeval = mean_datetime(timevals)
stats.update({"units": units, "time": timeval, "modtime": df.index_time})
return {id_: stats}
def stats(sesh, id_, time, area, variable):
'''Request and calculate summary statistics averaged across a region
For performing regional analysis, one typically wants to summarize
statistical information across a region. This call allows one to
request either a single timestep (or an average across all
timesteps), and averaged across all cells within the given region.
The stats call may only be called for a single data file and single
variable per invocation.
Args:
sesh (sqlalchemy.orm.session.Session): A database Session object
id_ (str): Unique id which is a key to the data file requested
time (int): Timestep integer (1-17) representing the time of year
area (str): WKT polygon of selected area
variable (str): Short name of the variable to be returned
Returns:
dict: Empty dictionary if model_id is not found in the database.
Otherwise, returns a single dict with the key of the file's
unique_id and the value consisting of a nested dictionary with
the following attributes: 'mean', 'stdev', 'min', 'max',
'median', 'ncells', 'units', 'time'.
For example ::
{'file0':
{
'mean': 303.97227647569446,
'stdev': 8.428096450998078,
'min': 288.71807861328125,
'max': 318.9695739746094,
'median': 301.61065673828125,
'ncells': 72,
'units': 'K',
'time': '1985-06-30T12:00:00Z'
}
}
There are two semi-error cases which should be mentioned, when
the filesystem is out of sync with the database.
1. The file pointed to by `id_` does not exist in the filesystem
2. The requested variable does not exist in the given file
In these cases, the numerical values will all be NaN, and the
results dict will be missing the 'units' and 'time' keys.
Raises:
None?
'''
try:
df = sesh.query(DataFile).filter(DataFile.unique_id == id_).one()
fname = df.filename
except NoResultFound:
return {}
try:
with open_nc(fname) as nc:
array = get_array(nc, fname, time, area, variable)
units = get_units_from_netcdf_file(nc, variable)
except Exception as e:
log.error(e)
return {id_: na_array_stats}
stats = array_stats(array)
query = sesh.query(Time.timestep).filter(Time.time_set_id == df.timeset.id)
if time:
query.filter(Time.time_idx == time)
timevals = [ t for t, in query.all() ]
timeval = mean_datetime(timevals)
stats.update({
'units': units,
'time': timeval.strftime('%Y-%m-%dT%H:%M:%SZ')
})
return {id_: stats}
