# Copyright (c) 2015-2025 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/>.
"""SEVIRI specific compositors."""
from __future__ import annotations
import logging
from .core import GenericCompositor, IncompatibleAreas
LOG = logging.getLogger(__name__)
[docs]
class RealisticColors(GenericCompositor):
"""Create a realistic colours composite for SEVIRI."""
def __call__(self, projectables, *args, **kwargs):
"""Generate the composite."""
projectables = self.match_data_arrays(projectables)
vis06 = projectables[0]
vis08 = projectables[1]
hrv = projectables[2]
try:
ch3 = 3.0 * hrv - vis06 - vis08
ch3.attrs = hrv.attrs
except ValueError:
raise IncompatibleAreas("Areas do not match")
ndvi = (vis08 - vis06) / (vis08 + vis06)
ndvi = ndvi.where(ndvi >= 0.0, 0.0)
ch1 = ndvi * vis06 + (1.0 - ndvi) * vis08
ch1.attrs = vis06.attrs
ch2 = ndvi * vis08 + (1.0 - ndvi) * vis06
ch2.attrs = vis08.attrs
res = super(RealisticColors, self).__call__((ch1, ch2, ch3),
*args, **kwargs)
return res