#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Copyright (c) 2020 Satpy developers
#
# satpy is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# satpy is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with satpy. If not, see <http://www.gnu.org/licenses/>.
"""The vii_l1b_nc reader tests package."""
import datetime
import os
import unittest
import uuid
import dask.array as da
import numpy as np
import xarray as xr
from netCDF4 import Dataset
from satpy.readers.vii_l1b_nc import ViiL1bNCFileHandler
from satpy.readers.vii_utils import MEAN_EARTH_RADIUS
TEST_FILE = 'test_file_vii_l1b_nc.nc'
[docs]class TestViiL1bNCFileHandler(unittest.TestCase):
"""Test the ViiL1bNCFileHandler reader."""
[docs] def setUp(self):
"""Set up the test."""
# Easiest way to test the reader is to create a test netCDF file on the fly
# uses a UUID to avoid permission conflicts during execution of tests in parallel
self.test_file_name = TEST_FILE + str(uuid.uuid1()) + ".nc"
with Dataset(self.test_file_name, 'w') as nc:
# Create data group
g1 = nc.createGroup('data')
# Add dimensions to data group
g1.createDimension('num_chan_solar', 11)
g1.createDimension('num_chan_thermal', 9)
g1.createDimension('num_pixels', 72)
g1.createDimension('num_lines', 600)
# Create calibration_data group
g1_1 = g1.createGroup('calibration_data')
# Add variables to data/calibration_data group
bt_a = g1_1.createVariable('bt_conversion_a', np.float32, dimensions=('num_chan_thermal',))
bt_a[:] = np.arange(9)
bt_b = g1_1.createVariable('bt_conversion_b', np.float32, dimensions=('num_chan_thermal',))
bt_b[:] = np.arange(9)
cw = g1_1.createVariable('channel_cw_thermal', np.float32, dimensions=('num_chan_thermal',))
cw[:] = np.arange(9)
isi = g1_1.createVariable('Band_averaged_solar_irradiance', np.float32, dimensions=('num_chan_solar',))
isi[:] = np.arange(11)
# Create measurement_data group
g1_2 = g1.createGroup('measurement_data')
# Add dimensions to data/measurement_data group
g1_2.createDimension('num_tie_points_act', 10)
g1_2.createDimension('num_tie_points_alt', 100)
# Add variables to data/measurement_data group
sza = g1_2.createVariable('solar_zenith', np.float32,
dimensions=('num_tie_points_act', 'num_tie_points_alt'))
sza[:] = 25.0
delta_lat = g1_2.createVariable('delta_lat', np.float32, dimensions=('num_pixels', 'num_lines'))
delta_lat[:] = 1.0
self.reader = ViiL1bNCFileHandler(
filename=self.test_file_name,
filename_info={
'creation_time': datetime.datetime(year=2017, month=9, day=22,
hour=22, minute=40, second=10),
'sensing_start_time': datetime.datetime(year=2017, month=9, day=20,
hour=12, minute=30, second=30),
'sensing_end_time': datetime.datetime(year=2017, month=9, day=20,
hour=18, minute=30, second=50)
},
filetype_info={}
)
[docs] def tearDown(self):
"""Remove the previously created test file."""
# Catch Windows PermissionError for removing the created test file.
try:
os.remove(self.test_file_name)
except OSError:
pass
[docs] def test_calibration_functions(self):
"""Test the calibration functions."""
radiance = np.array([[1.0, 2.0, 5.0], [7.0, 10.0, 20.0]])
cw = 13.0
a = 3.0
b = 100.0
bt = self.reader._calibrate_bt(radiance, cw, a, b)
expected_bt = np.array([[675.04993213, 753.10301462, 894.93149648],
[963.20401882, 1048.95086402, 1270.95546218]])
self.assertTrue(np.allclose(bt, expected_bt))
angle_factor = 0.4
isi = 2.0
refl = self.reader._calibrate_refl(radiance, angle_factor, isi)
expected_refl = np.array([[0.628318531, 1.256637061, 3.141592654],
[4.398229715, 6.283185307, 12.56637061]])
self.assertTrue(np.allclose(refl, expected_refl))
[docs] def test_functions(self):
"""Test the functions."""
# Checks that the _perform_orthorectification function is correctly executed
variable = xr.DataArray(
dims=('num_pixels', 'num_lines'),
name='test_name',
attrs={
'key_1': 'value_1',
'key_2': 'value_2'
},
data=da.from_array(np.ones((72, 600)))
)
orthorect_variable = self.reader._perform_orthorectification(variable, 'data/measurement_data/delta_lat')
expected_values = np.degrees(np.ones((72, 600)) / MEAN_EARTH_RADIUS) + np.ones((72, 600))
self.assertTrue(np.allclose(orthorect_variable.values, expected_values))
# Checks that the _perform_calibration function is correctly executed in all cases
# radiance calibration: return value is simply a copy of the variable
return_variable = self.reader._perform_calibration(variable, {'calibration': 'radiance'})
self.assertTrue(np.all(return_variable == variable))
# invalid calibration: raises a ValueError
with self.assertRaises(ValueError):
self.reader._perform_calibration(variable,
{'calibration': 'invalid', 'name': 'test'})
# brightness_temperature calibration: checks that the return value is correct
calibrated_variable = self.reader._perform_calibration(variable,
{'calibration': 'brightness_temperature',
'chan_thermal_index': 3})
expected_values = np.ones((72, 600)) * 302007.42728603
self.assertTrue(np.allclose(calibrated_variable.values, expected_values))
# reflectance calibration: checks that the return value is correct
calibrated_variable = self.reader._perform_calibration(variable,
{'calibration': 'reflectance',
'wavelength': [0.658, 0.668, 0.678],
'chan_solar_index': 2})
expected_values = np.ones((72, 600)) * 1.733181982 * (0.678 - 0.658)
self.assertTrue(np.allclose(calibrated_variable.values, expected_values))