Failed to load AVHRR LAC data

[BigShuiTai]

Describe the bug
Failed to load AVHRR LAC data

To Reproduce

# Your code here
scn = Scene(['NSS.LHRR.NF.D88278.S0708.E0716.B1963535.WI'], reader='avhrr_l1b_gaclac')
scn.load([10.8])

Actual results

/root/miniconda3/lib/python3.8/site-packages/pygac/reader.py:274: RuntimeWarning: Unexpected number of scanlines!
  warnings.warn("Unexpected number of scanlines!",
Failed to load DataID(name='longitude', resolution=1050, modifiers=()) from <GACLACFile: 'NSS.LHRR.NF.D88278.S0708.E0716.B1963535.WI'>
Traceback (most recent call last):
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/yaml_reader.py", line 687, in _load_dataset
    projectable = fh.get_dataset(dsid, ds_info)
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/avhrr_l1b_gaclac.py", line 132, in get_dataset
    self.read_raw_data()
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/avhrr_l1b_gaclac.py", line 126, in read_raw_data
    self.reader.read(self.filename)
  File "/root/miniconda3/lib/python3.8/site-packages/pygac/pod_reader.py", line 298, in read
    self.spacecraft_name = self.spacecraft_names[self.spacecraft_id]
KeyError: 32
Could not load dataset 'DataID(name='longitude', resolution=1050, modifiers=())': "Could not load DataID(name='longitude', resolution=1050, modifiers=()) from any provided files"
Traceback (most recent call last):
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/yaml_reader.py", line 839, in _load_dataset_with_area
    ds = self._load_dataset_data(file_handlers, dsid, **kwargs)
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/yaml_reader.py", line 711, in _load_dataset_data
    proj = self._load_dataset(dsid, ds_info, file_handlers, **kwargs)
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/yaml_reader.py", line 696, in _load_dataset
    raise KeyError(
KeyError: "Could not load DataID(name='longitude', resolution=1050, modifiers=()) from any provided files"
/root/miniconda3/lib/python3.8/site-packages/numpy/core/fromnumeric.py:3440: RuntimeWarning: Mean of empty slice.
  return _methods._mean(a, axis=axis, dtype=dtype,
/root/miniconda3/lib/python3.8/site-packages/numpy/core/_methods.py:189: RuntimeWarning: invalid value encountered in double_scalars
  ret = ret.dtype.type(ret / rcount)
Could not load dataset 'DataID(name='latitude', resolution=1050, modifiers=())': max() arg is an empty sequence
Traceback (most recent call last):
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/yaml_reader.py", line 839, in _load_dataset_with_area
    ds = self._load_dataset_data(file_handlers, dsid, **kwargs)
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/yaml_reader.py", line 711, in _load_dataset_data
    proj = self._load_dataset(dsid, ds_info, file_handlers, **kwargs)
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/yaml_reader.py", line 687, in _load_dataset
    projectable = fh.get_dataset(dsid, ds_info)
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/avhrr_l1b_gaclac.py", line 136, in get_dataset
    _, data = self.reader.get_lonlat()
  File "/root/miniconda3/lib/python3.8/site-packages/pygac/reader.py", line 560, in get_lonlat
    self.update_meta_data()
  File "/root/miniconda3/lib/python3.8/site-packages/pygac/reader.py", line 491, in update_meta_data
    self.get_sun_earth_distance_correction())
  File "/root/miniconda3/lib/python3.8/site-packages/pygac/reader.py", line 483, in get_sun_earth_distance_correction
    self.get_times()
  File "/root/miniconda3/lib/python3.8/site-packages/pygac/reader.py", line 429, in get_times
    year, jday, msec = self.correct_times_median(year=year, jday=jday,
  File "/root/miniconda3/lib/python3.8/site-packages/pygac/reader.py", line 841, in correct_times_median
    jday = np.where(if_wrong_jday < 0, max(jday), jday)
ValueError: max() arg is an empty sequence
Could not load dataset 'DataID(name='4', wavelength=WavelengthRange(min=10.3, central=10.8, max=11.3, unit='µm'), resolution=1050, calibration=<calibration.brightness_temperature>, modifiers=())': max() arg is an empty sequence
Traceback (most recent call last):
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/yaml_reader.py", line 839, in _load_dataset_with_area
    ds = self._load_dataset_data(file_handlers, dsid, **kwargs)
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/yaml_reader.py", line 711, in _load_dataset_data
    proj = self._load_dataset(dsid, ds_info, file_handlers, **kwargs)
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/yaml_reader.py", line 687, in _load_dataset
    projectable = fh.get_dataset(dsid, ds_info)
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/avhrr_l1b_gaclac.py", line 160, in get_dataset
    data = self._get_channel(key)
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/avhrr_l1b_gaclac.py", line 259, in _get_channel
    self.calib_channels = self.reader.get_calibrated_channels()
  File "/root/miniconda3/lib/python3.8/site-packages/pygac/reader.py", line 503, in get_calibrated_channels
    self.get_times()
  File "/root/miniconda3/lib/python3.8/site-packages/pygac/reader.py", line 429, in get_times
    year, jday, msec = self.correct_times_median(year=year, jday=jday,
  File "/root/miniconda3/lib/python3.8/site-packages/pygac/reader.py", line 841, in correct_times_median
    jday = np.where(if_wrong_jday < 0, max(jday), jday)
ValueError: max() arg is an empty sequence
The following datasets were not created and may require resampling to be generated: DataID(name='4', wavelength=WavelengthRange(min=10.3, central=10.8, max=11.3, unit='µm'), resolution=1050, calibration=<calibration.brightness_temperature>, modifiers=())

Environment Info:

• OS: CentOS 7.6.1810 x86_64
• Satpy Version: 0.33.0

NSS.LHRR.NF.D88278.S0708.E0716.B1963535.zip

[mraspaud]

Thanks for reporting this! Do you get this error with several files or just this one?

[BigShuiTai]

Thanks for reporting this! Do you get this error with several files or just this one?

I have tested another file, but not the error I got before:

# code
scn = Scene(['NSS.LHRR.ND.D91330.S2140.E2146.B0278888.WI'], reader='avhrr_l1b_gaclac')
scn.load([10.8])

# error
Traceback (most recent call last):
  File "avhrr.py", line 27, in <module>
    scn.load([10.8])
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/scene.py", line 1205, in load
    self._read_datasets_from_storage(**kwargs)
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/scene.py", line 1225, in _read_datasets_from_storage
    return self._read_dataset_nodes_from_storage(nodes, **kwargs)
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/scene.py", line 1231, in _read_dataset_nodes_from_storage
    loaded_datasets = self._load_datasets_by_readers(reader_datasets, **kwargs)
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/scene.py", line 1256, in _load_datasets_by_readers
    new_datasets = reader_instance.load(ds_ids, **kwargs)
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/yaml_reader.py", line 943, in load
    ds = self._load_dataset_with_area(dsid, coords, **kwargs)
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/yaml_reader.py", line 839, in _load_dataset_with_area
    ds = self._load_dataset_data(file_handlers, dsid, **kwargs)
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/yaml_reader.py", line 711, in _load_dataset_data
    proj = self._load_dataset(dsid, ds_info, file_handlers, **kwargs)
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/yaml_reader.py", line 687, in _load_dataset
    projectable = fh.get_dataset(dsid, ds_info)
  File "/root/miniconda3/lib/python3.8/site-packages/satpy/readers/avhrr_l1b_gaclac.py", line 136, in get_dataset
    _, data = self.reader.get_lonlat()
  File "/root/miniconda3/lib/python3.8/site-packages/pygac/reader.py", line 569, in get_lonlat
    self._adjust_clock_drift()
  File "/root/miniconda3/lib/python3.8/site-packages/pygac/pod_reader.py", line 490, in _adjust_clock_drift
    missed_lons, missed_lats = self._compute_missing_lonlat(missed_utcs)
  File "/root/miniconda3/lib/python3.8/site-packages/pygac/pod_reader.py", line 431, in _compute_missing_lonlat
    tle1, tle2 = self.get_tle_lines()
  File "/root/miniconda3/lib/python3.8/site-packages/pygac/reader.py", line 690, in get_tle_lines
    tle_data = self.read_tle_file(self.get_tle_file())
  File "/root/miniconda3/lib/python3.8/site-packages/pygac/reader.py", line 666, in get_tle_file
    raise RuntimeError("TLE directory not specified!")
RuntimeError: TLE directory not specified!

NSS.LHRR.ND.D91330.S2140.E2146.B0278888.zip

[mraspaud]

That second error I'm more familiar with, you need to have a file with the TLE data to be able to navigate the scene. Have a look at the documentation for Pygac to set it up.

[BigShuiTai]

That second error I'm more familiar with, you need to have a file with the TLE data to be able to navigate the scene. Have a look at the documentation for Pygac to set it up.

Thanks for your explanation! I will try it again with your suggestion.