Tidy L3 CAMEL reader and add tests.

satpy/etc/readers/camel_l3_nc.yaml

@@ -15,7 +15,7 @@ file_types:
     camel_emis_file:
         file_reader: !!python/name:satpy.readers.camel_l3_nc.CAMELL3NCFileHandler
         file_patterns:
-         - 'CAM5K30EM_emis_{start_time:%Y%m}_V{version:3s}.nc'
+         - 'CAM5K30EM_emis_{start_period:%Y%m}_V{version:3s}.nc'
 
 
 datasets:

satpy/readers/camel_l3_nc.py

@@ -53,8 +53,6 @@ def __init__(self, filename, filename_info, filetype_info):
             raise ValueError("Only 0.05 degree grid data is supported.")
         if self.nc.attrs["geospatial_lat_resolution"] != "0.05 degree grid ":
             raise ValueError("Only 0.05 degree grid data is supported.")
-        if self.nc.sizes["spectra"] != 13:
-            raise ValueError("Only CAMEL files with 13 spectral bands are supported.")
 
         self.nlines = self.nc.sizes["latitude"]
         self.ncols = self.nc.sizes["longitude"]
@@ -82,6 +80,8 @@ def get_dataset(self, key, info):
 
         # For the emissivity there are multiple bands, so we need to select the correct one
         if var == "camel_emis":
+            if info["band_id"] >= variable.shape[2]:
+                raise ValueError("Band id requested is larger than dataset.")
             variable = variable[:, :, info["band_id"]]
 
         # Rename the latitude and longitude dimensions to x and y

satpy/tests/reader_tests/test_camel_l3_nc.py

@@ -0,0 +1,133 @@
+"""Tests for the CAMEL L3 netCDF reader."""
+
+import datetime as dt
+
+import numpy as np
+import pytest
+import xarray as xr
+
+from satpy.readers.camel_l3_nc import CAMELL3NCFileHandler
+from satpy.tests.utils import make_dataid
+
+rng = np.random.default_rng()
+ndvi_data = rng.integers(0, 1000, (3600, 7200), dtype=np.int16)
+emis_data = rng.integers(0, 1000, (3600, 7200, 5), dtype=np.int16)
+
+lon_data = np.arange(-180, 180, 0.05)
+lat_data = np.arange(-90, 90, 0.05)
+
+start_time = dt.datetime(2023, 8, 1, 0, 0, 0)
+end_time = dt.datetime(2023, 9, 1, 0, 0, 0)
+
+fill_val = -999
+scale_val = 0.001
+
+dimensions = {"longitude": 7200, "latitude": 3600, "spectra": 13}
+
+exp_ext = (-180.0, -90.0, 180.0, 90.0)
+
+global_attrs = {"time_coverage_start": start_time.strftime("%Y-%m-%d %H:%M:%SZ"),
+                "time_coverage_end": end_time.strftime("%Y-%m-%d %H:%M:%SZ"),
+                "geospatial_lon_resolution": "0.05 degree grid ",
+                "geospatial_lat_resolution": "0.05 degree grid ",
+                }
+
+bad_attrs1 = global_attrs.copy()
+bad_attrs1["geospatial_lon_resolution"] = "0.1 degree grid "
+bad_attrs2 = global_attrs.copy()
+bad_attrs2["geospatial_lat_resolution"] = "0.1 degree grid "
+
+
+def _make_ds(the_attrs, tmp_factory):
+    """Make a dataset for use in tests."""
+    fname = f'{tmp_factory.mktemp("data")}/CAM5K30EM_emis_202308_V003.nc'
+    ds = xr.Dataset({"aster_ndvi": (["Rows", "Columns"], ndvi_data),
+                     "camel_emis": (["latitude", "longitude", "spectra"], emis_data)},
+                    coords={"latitude": (["Rows"], lat_data),
+                            "longitude": (["Columns"], lon_data)},
+                    attrs=the_attrs)
+    ds.to_netcdf(fname)
+    return fname
+
+
+def camel_l3_filehandler(fname):
+    """Instantiate a Filehandler."""
+    fileinfo = {"start_period": "202308",
+                "version": "003"}
+    filetype = None
+    fh = CAMELL3NCFileHandler(fname, fileinfo, filetype)
+    return fh
+
+
+@pytest.fixture(scope="session")
+def camel_filename(tmp_path_factory):
+    """Create a fake camel l3 file."""
+    return _make_ds(global_attrs, tmp_path_factory)
+
+
+@pytest.fixture(scope="session")
+def camel_filename_bad1(tmp_path_factory):
+    """Create a fake camel l3 file."""
+    return _make_ds(bad_attrs1, tmp_path_factory)
+
+
+@pytest.fixture(scope="session")
+def camel_filename_bad2(tmp_path_factory):
+    """Create a fake camel l3 file."""
+    return _make_ds(bad_attrs2, tmp_path_factory)
+
+
+def test_startend(camel_filename):
+    """Test start and end times are set correctly."""
+    fh = camel_l3_filehandler(camel_filename)
+    assert fh.start_time == start_time
+    assert fh.end_time == end_time
+
+
+def test_camel_l3_area_def(camel_filename, caplog):
+    """Test reader handles area definition correctly."""
+    ps = "+proj=longlat +datum=WGS84 +no_defs +type=crs"
+
+    # Check case where input data is correct size.
+    fh = camel_l3_filehandler(camel_filename)
+    ndvi_id = make_dataid(name="aster_ndvi")
+    area_def = fh.get_area_def(ndvi_id)
+    assert area_def.width == dimensions["longitude"]
+    assert area_def.height == dimensions["latitude"]
+    assert np.allclose(area_def.area_extent, exp_ext)
+
+    assert area_def.proj4_string == ps
+
+
+def test_bad_longitude(camel_filename_bad1):
+    """Check case where longitude grid is not correct."""
+    with pytest.raises(ValueError, match="Only 0.05 degree grid data is supported."):
+        camel_l3_filehandler(camel_filename_bad1)
+
+
+def test_bad_latitude(camel_filename_bad2):
+    """Check case where latitude grid is not correct."""
+    with pytest.raises(ValueError, match="Only 0.05 degree grid data is supported."):
+        camel_l3_filehandler(camel_filename_bad2)
+
+
+def test_load_ndvi_data(camel_filename):
+    """Test that data is loaded successfully."""
+    fh = camel_l3_filehandler(camel_filename)
+    ndvi_id = make_dataid(name="aster_ndvi")
+    ndvi = fh.get_dataset(ndvi_id, {"file_key": "aster_ndvi"})
+    assert np.allclose(ndvi.data, ndvi_data)
+
+
+def test_load_emis_data(camel_filename):
+    """Test that data is loaded successfully."""
+    fh = camel_l3_filehandler(camel_filename)
+    emis_id = make_dataid(name="camel_emis")
+
+    # This is correct data
+    emis = fh.get_dataset(emis_id, {"file_key": "camel_emis", "band_id": 2})
+    assert np.allclose(emis.data, emis_data[:, :, 2])
+
+    # This will fail as we are requesting a band too high data
+    with pytest.raises(ValueError, match="Band id requested is larger than dataset."):
+        fh.get_dataset(emis_id, {"file_key": "camel_emis", "band_id": 12})