# Copyright (c) 2018 Satpy developers
#
# This file is part of satpy.
#
# 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/>.
"""Tests for spectral correction compositors."""
import warnings
import dask.array as da
import numpy as np
import pytest
import xarray as xr
from satpy.composites.spectral import GreenCorrector, HybridGreen, NDVIHybridGreen, SpectralBlender
[docs]class TestSpectralComposites:
"""Test composites for spectral channel corrections."""
[docs] def setup_method(self):
"""Initialize channels."""
rows = 5
cols = 10
self.c01 = xr.DataArray(da.zeros((rows, cols), chunks=25) + 0.20, dims=('y', 'x'), attrs={'name': 'C02'})
self.c02 = xr.DataArray(da.zeros((rows, cols), chunks=25) + 0.30, dims=('y', 'x'), attrs={'name': 'C03'})
self.c03 = xr.DataArray(da.zeros((rows, cols), chunks=25) + 0.40, dims=('y', 'x'), attrs={'name': 'C04'})
[docs] def test_bad_lengths(self):
"""Test that error is raised if the amount of channels to blend does not match the number of weights."""
comp = SpectralBlender('blended_channel', fractions=(0.3, 0.7), prerequisites=(0.51, 0.85),
standard_name='toa_bidirectional_reflectance')
with pytest.raises(ValueError):
comp((self.c01, self.c02, self.c03))
[docs] def test_spectral_blender(self):
"""Test the base class for spectral blending of channels."""
comp = SpectralBlender('blended_channel', fractions=(0.3, 0.4, 0.3), prerequisites=(0.51, 0.65, 0.85),
standard_name='toa_bidirectional_reflectance')
res = comp((self.c01, self.c02, self.c03))
assert isinstance(res, xr.DataArray)
assert isinstance(res.data, da.Array)
assert res.attrs['name'] == 'blended_channel'
assert res.attrs['standard_name'] == 'toa_bidirectional_reflectance'
data = res.compute()
np.testing.assert_allclose(data, 0.3)
[docs] def test_hybrid_green(self):
"""Test hybrid green correction of the 'green' band."""
comp = HybridGreen('hybrid_green', fraction=0.15, prerequisites=(0.51, 0.85),
standard_name='toa_bidirectional_reflectance')
res = comp((self.c01, self.c03))
assert isinstance(res, xr.DataArray)
assert isinstance(res.data, da.Array)
assert res.attrs['name'] == 'hybrid_green'
assert res.attrs['standard_name'] == 'toa_bidirectional_reflectance'
data = res.compute()
np.testing.assert_allclose(data, 0.23)
[docs] def test_ndvi_hybrid_green(self):
"""Test NDVI-scaled hybrid green correction of 'green' band."""
self.c01 = xr.DataArray(da.from_array([[0.25, 0.30], [0.20, 0.30]], chunks=25),
dims=('y', 'x'), attrs={'name': 'C02'})
self.c02 = xr.DataArray(da.from_array([[0.25, 0.30], [0.25, 0.35]], chunks=25),
dims=('y', 'x'), attrs={'name': 'C03'})
self.c03 = xr.DataArray(da.from_array([[0.35, 0.35], [0.28, 0.65]], chunks=25),
dims=('y', 'x'), attrs={'name': 'C04'})
comp = NDVIHybridGreen('ndvi_hybrid_green', limits=(0.15, 0.05), prerequisites=(0.51, 0.65, 0.85),
standard_name='toa_bidirectional_reflectance')
res = comp((self.c01, self.c02, self.c03))
assert isinstance(res, xr.DataArray)
assert isinstance(res.data, da.Array)
assert res.attrs['name'] == 'ndvi_hybrid_green'
assert res.attrs['standard_name'] == 'toa_bidirectional_reflectance'
data = res.values
np.testing.assert_array_almost_equal(data, np.array([[0.2633, 0.3071], [0.2115, 0.3420]]), decimal=4)
[docs] def test_green_corrector(self):
"""Test the deprecated class for green corrections."""
with warnings.catch_warnings():
warnings.filterwarnings("ignore", category=UserWarning, message=r'.*deprecated.*')
comp = GreenCorrector('blended_channel', fractions=(0.85, 0.15), prerequisites=(0.51, 0.85),
standard_name='toa_bidirectional_reflectance')
res = comp((self.c01, self.c03))
assert isinstance(res, xr.DataArray)
assert isinstance(res.data, da.Array)
assert res.attrs['name'] == 'blended_channel'
assert res.attrs['standard_name'] == 'toa_bidirectional_reflectance'
data = res.compute()
np.testing.assert_allclose(data, 0.23)