# 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/>.
"""Compositors performing arithmetic operations."""
from __future__ import annotations
import logging
from satpy.dataset import combine_metadata
from .core import CompositeBase
LOG = logging.getLogger(__name__)
[docs]
class DifferenceCompositor(CompositeBase):
"""Make the difference of two data arrays."""
def __call__(self, projectables, nonprojectables=None, **attrs):
"""Generate the composite."""
if len(projectables) != 2:
raise ValueError("Expected 2 datasets, got %d" % (len(projectables),))
projectables = self.match_data_arrays(projectables)
info = combine_metadata(*projectables)
info["name"] = self.attrs["name"]
info.update(self.attrs) # attrs from YAML/__init__
info.update(attrs) # overwriting of DataID properties
proj = projectables[0] - projectables[1]
proj.attrs = info
return proj
[docs]
class RatioCompositor(CompositeBase):
"""Make the ratio of two data arrays."""
def __call__(self, projectables, nonprojectables=None, **info):
"""Generate the composite."""
if len(projectables) != 2:
raise ValueError("Expected 2 datasets, got %d" % (len(projectables),))
projectables = self.match_data_arrays(projectables)
info = combine_metadata(*projectables)
info.update(self.attrs)
proj = projectables[0] / projectables[1]
proj.attrs = info
return proj
[docs]
class SumCompositor(CompositeBase):
"""Make the sum of two data arrays."""
def __call__(self, projectables, nonprojectables=None, **info):
"""Generate the composite."""
if len(projectables) != 2:
raise ValueError("Expected 2 datasets, got %d" % (len(projectables),))
projectables = self.match_data_arrays(projectables)
info = combine_metadata(*projectables)
info["name"] = self.attrs["name"]
proj = projectables[0] + projectables[1]
proj.attrs = info
return proj