Refactor resampler module to submodules

doc/source/generate_area_def_list.py

@@ -1,7 +1,8 @@
 """Generate the area definition list restructuredtext document.
 
 This should be run once before generating the sphinx documentation to
-produce the ``area_def_list.rst`` file referenced by ``satpy/resample.py``.
+produce the ``area_def_list.rst`` file referenced by
+``satpy/resample/__init__.py``.
 
 """
 import logging
@@ -19,7 +20,7 @@
 from pyresample.utils.proj4 import ignore_pyproj_proj_warnings
 from reader_table import rst_table_header, rst_table_row
 
-from satpy.resample import get_area_file
+from satpy.area_utils import get_area_file
 
 logger = logging.getLogger(__name__)
 

satpy/area_utils.py

@@ -0,0 +1,43 @@
+#!/usr/bin/env python
+# 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/>.
+"""Utility functions for area definitions."""
+from ._config import config_search_paths, get_config_path
+
+
+def get_area_file():
+    """Find area file(s) to use.
+
+    The files are to be named `areas.yaml` or `areas.def`.
+    """
+    paths = config_search_paths("areas.yaml")
+    if paths:
+        return paths
+    else:
+        return get_config_path("areas.def")
+
+
+def get_area_def(area_name):
+    """Get the definition of *area_name* from file.
+
+    The file is defined to use is to be placed in the $SATPY_CONFIG_PATH
+    directory, and its name is defined in satpy's configuration file.
+    """
+    try:
+        from pyresample import parse_area_file
+    except ImportError:
+        from pyresample.utils import parse_area_file
+    return parse_area_file(get_area_file(), area_name)[0]

satpy/composites/__init__.py

@@ -1597,7 +1597,7 @@ def __init__(self, name, filename=None, url=None, known_hash=None, area=None,  #
         self._known_hash = known_hash
         self.area = None
         if area is not None:
-            from satpy.resample import get_area_def
+            from satpy.area_utils import get_area_def
             self.area = get_area_def(area)
 
         super(StaticImageCompositor, self).__init__(name, **kwargs)

satpy/coords_utils.py

@@ -0,0 +1,131 @@
+#!/usr/bin/env python
+# 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/>.
+"""Utility functions for coordinates."""
+
+import logging
+
+import xarray as xr
+
+LOG = logging.getLogger(__name__)
+
+
+def add_xy_coords(data_arr, area, crs=None):
+    """Assign x/y coordinates to DataArray from provided area.
+
+    If 'x' and 'y' coordinates already exist then they will not be added.
+
+    Args:
+        data_arr (xarray.DataArray): data object to add x/y coordinates to
+        area (pyresample.geometry.AreaDefinition): area providing the
+            coordinate data.
+        crs (pyproj.crs.CRS or None): CRS providing additional information
+            about the area's coordinate reference system if available.
+            Requires pyproj 2.0+.
+
+    Returns (xarray.DataArray): Updated DataArray object
+
+    """
+    if "x" in data_arr.coords and "y" in data_arr.coords:
+        # x/y coords already provided
+        return data_arr
+    if "x" not in data_arr.dims or "y" not in data_arr.dims:
+        # no defined x and y dimensions
+        return data_arr
+    if not hasattr(area, "get_proj_vectors"):
+        return data_arr
+    x, y = area.get_proj_vectors()
+
+    # convert to DataArrays
+    y_attrs = {}
+    x_attrs = {}
+
+    _check_crs_units(crs, x_attrs, y_attrs)
+
+    y = xr.DataArray(y, dims=("y",), attrs=y_attrs)
+    x = xr.DataArray(x, dims=("x",), attrs=x_attrs)
+    return data_arr.assign_coords(y=y, x=x)
+
+
+def _check_crs_units(crs, x_attrs, y_attrs):
+    if crs is None:
+        return
+    units = crs.axis_info[0].unit_name
+    # fix udunits/CF standard units
+    units = units.replace("metre", "meter")
+    if units == "degree":
+        y_attrs["units"] = "degrees_north"
+        x_attrs["units"] = "degrees_east"
+    else:
+        y_attrs["units"] = units
+        x_attrs["units"] = units
+
+
+def add_crs_xy_coords(data_arr, area):
+    """Add :class:`pyproj.crs.CRS` and x/y or lons/lats to coordinates.
+
+    For SwathDefinition or GridDefinition areas this will add a
+    `crs` coordinate and coordinates for the 2D arrays of `lons` and `lats`.
+
+    For AreaDefinition areas this will add a `crs` coordinate and the
+    1-dimensional `x` and `y` coordinate variables.
+
+    Args:
+        data_arr (xarray.DataArray): DataArray to add the 'crs'
+            coordinate.
+        area (pyresample.geometry.AreaDefinition): Area to get CRS
+            information from.
+
+    """
+    from pyresample.geometry import SwathDefinition
+
+    crs, data_arr = _add_crs(area, data_arr)
+
+    # Add x/y coordinates if possible
+    if isinstance(area, SwathDefinition):
+        # add lon/lat arrays for swath definitions
+        # SwathDefinitions created by Satpy should be assigning DataArray
+        # objects as the lons/lats attributes so use those directly to
+        # maintain original .attrs metadata (instead of converting to dask
+        # array).
+        lons = area.lons
+        lats = area.lats
+        lons.attrs.setdefault("standard_name", "longitude")
+        lons.attrs.setdefault("long_name", "longitude")
+        lons.attrs.setdefault("units", "degrees_east")
+        lats.attrs.setdefault("standard_name", "latitude")
+        lats.attrs.setdefault("long_name", "latitude")
+        lats.attrs.setdefault("units", "degrees_north")
+        # See https://github.com/pydata/xarray/issues/3068
+        # data_arr = data_arr.assign_coords(longitude=lons, latitude=lats)
+    else:
+        # Gridded data (AreaDefinition/StackedAreaDefinition)
+        data_arr = add_xy_coords(data_arr, area, crs=crs)
+    return data_arr
+
+
+def _add_crs(area, data_arr):
+    from pyproj import CRS
+
+    if hasattr(area, "crs"):
+        crs = area.crs
+    else:
+        # default lat/lon projection
+        latlon_proj = "+proj=latlong +datum=WGS84 +ellps=WGS84"
+        proj_str = getattr(area, "proj_str", latlon_proj)
+        crs = CRS.from_string(proj_str)
+    data_arr = data_arr.assign_coords(crs=crs)
+    return crs, data_arr

satpy/modifiers/parallax.py

@@ -51,7 +51,7 @@
 from pyresample.geometry import SwathDefinition
 
 from satpy.modifiers import ModifierBase
-from satpy.resample import resample_dataset
+from satpy.resample.base import resample_dataset
 from satpy.utils import get_satpos, lonlat2xyz, xyz2lonlat
 
 logger = logging.getLogger(__name__)

satpy/readers/cmsaf_claas2.py

@@ -2,8 +2,8 @@
 
 import datetime
 
+from satpy.area_utils import get_area_def
 from satpy.readers.core.netcdf import NetCDF4FileHandler
-from satpy.resample import get_area_def
 
 
 def _is_georef_offset_present(date):

satpy/readers/core/yaml_reader.py

@@ -42,10 +42,11 @@
 
 from satpy import DatasetDict
 from satpy._compat import cache
+from satpy.area_utils import get_area_def
 from satpy.aux_download import DataDownloadMixin
+from satpy.coords_utils import add_crs_xy_coords
 from satpy.dataset import DataID, DataQuery, get_key
 from satpy.dataset.dataid import default_co_keys_config, default_id_keys_config, get_keys_from_config
-from satpy.resample import add_crs_xy_coords, get_area_def
 from satpy.utils import recursive_dict_update
 
 logger = logging.getLogger(__name__)
@@ -735,7 +736,7 @@
     def _load_dataset_data(self, file_handlers, dsid, **kwargs):
         ds_info = self.all_ids[dsid]
         proj = self._load_dataset(dsid, ds_info, file_handlers, **kwargs)
         # FIXME: areas could be concatenated here
         # Update the metadata
         proj.attrs["start_time"] = file_handlers[0].start_time
         proj.attrs["end_time"] = file_handlers[-1].end_time

satpy/readers/eum_l2_bufr.py

@@ -32,11 +32,11 @@
 import numpy as np
 import xarray as xr
 
+from satpy.area_utils import get_area_def
 from satpy.readers.core._geos_area import get_geos_area_naming
 from satpy.readers.core.eum import get_service_mode, recarray2dict
 from satpy.readers.core.file_handlers import BaseFileHandler
 from satpy.readers.core.seviri import mpef_product_header
-from satpy.resample import get_area_def
 from satpy.utils import get_legacy_chunk_size
 
 try:

satpy/readers/fci_l2_nc.py

@@ -24,11 +24,11 @@
 from pyresample import geometry
 
 from satpy._compat import cached_property
+from satpy.area_utils import get_area_def
 from satpy.readers.core._geos_area import get_geos_area_naming, make_ext
 from satpy.readers.core.eum import get_service_mode
 from satpy.readers.core.fci import platform_name_translate
 from satpy.readers.core.file_handlers import BaseFileHandler
-from satpy.resample import get_area_def
 from satpy.utils import get_legacy_chunk_size
 
 logger = logging.getLogger(__name__)

satpy/readers/gerb_l2_hr_h5.py

@@ -25,8 +25,8 @@
 import datetime as dt
 import logging
 
+from satpy.area_utils import get_area_def
 from satpy.readers.core.hdf5 import HDF5FileHandler
-from satpy.resample import get_area_def
 
 LOG = logging.getLogger(__name__)
 

satpy/readers/hsaf_h5.py

@@ -26,8 +26,8 @@
 import numpy as np
 import xarray as xr
 
+from satpy.area_utils import get_area_def
 from satpy.readers.core.file_handlers import BaseFileHandler
-from satpy.resample import get_area_def
 from satpy.utils import get_legacy_chunk_size
 
 LOG = logging.getLogger(__name__)

satpy/readers/li_l2_nc.py

@@ -80,8 +80,8 @@
 import numpy as np
 import xarray as xr
 
+from satpy.area_utils import get_area_def
 from satpy.readers.core.li_nc import LINCFileHandler
-from satpy.resample import get_area_def
 from satpy.utils import get_legacy_chunk_size
 
 logger = logging.getLogger(__name__)