Adapt reader mviri_l1b_fiduceo_nc

AUTHORS.md

@@ -44,6 +44,7 @@ The following people have made contributions to this project:
 - [Johannes Johansson (JohannesSMHI)](https://github.com/JohannesSMHI)
 - [Sauli Joro (sjoro)](https://github.com/sjoro)
 - [Janne Kotro (jkotro)](https://github.com/jkotro)
+- [Beke Kremmling (bkremmli)](https://github.com/bkremmli) - Deutscher Wetterdienst
 - [Ralph Kuehn (ralphk11)](https://github.com/ralphk11)
 - [Panu Lahtinen (pnuu)](https://github.com/pnuu)
 - [Jussi Leinonen (jleinonen)](https://github.com/jleinonen) - meteoswiss

satpy/readers/mviri_l1b_fiduceo_nc.py

@@ -157,6 +157,7 @@
 import warnings
 
 import dask.array as da
+import numpy
 import numpy as np
 import xarray as xr
 
@@ -513,11 +514,19 @@ def get_time(self):
         """Get time coordinate.
 
         Variable is sometimes named "time" and sometimes "time_ir_wv".
+        FillValues in time are set to NaT.
         """
         try:
-            return self["time_ir_wv"]
+            time = self["time_ir_wv"]
         except KeyError:
-            return self["time"]
+            time = self["time"]
+
+        timeOffset = time.attrs["add_offset"]
+        condition = time == time.attrs["_FillValue"]
+
+        time = xr.where(condition, numpy.nan, time + timeOffset)
+        time = (time*1e9).astype("datetime64[ns]")
+        return time
 
     def get_xy_coords(self, resolution):
         """Get x and y coordinates for the given resolution."""
@@ -555,11 +564,14 @@ def __init__(self, filename, filename_info, filetype_info,  # noqa: D417
         self.mask_bad_quality = mask_bad_quality
         nc_raw = xr.open_dataset(
             filename,
-            chunks={"x": CHUNK_SIZE,
-                    "y": CHUNK_SIZE,
-                    "x_ir_wv": CHUNK_SIZE,
-                    "y_ir_wv": CHUNK_SIZE}
+            # chunks={"x": CHUNK_SIZE,
+            #         "y": CHUNK_SIZE,
+            #         "x_ir_wv": CHUNK_SIZE,
+            #         "y_ir_wv": CHUNK_SIZE},
+            decode_times=False,
+            decode_cf=False
         )
+
         self.nc = DatasetWrapper(nc_raw)
 
         # Projection longitude is not provided in the file, read it from the

satpy/tests/reader_tests/test_mviri_l1b_fiduceo_nc.py

@@ -61,8 +61,8 @@
     {"sun_earth_distance_correction_applied": True,
      "sun_earth_distance_correction_factor": 1.}
 )
-acq_time_vis_exp = [np.datetime64("1970-01-01 00:30").astype("datetime64[ns]"),
-                    np.datetime64("1970-01-01 00:30").astype("datetime64[ns]"),
+acq_time_vis_exp = [np.datetime64("NaT").astype("datetime64[ns]"),
+                    np.datetime64("NaT").astype("datetime64[ns]"),
                     np.datetime64("1970-01-01 02:30").astype("datetime64[ns]"),
                     np.datetime64("1970-01-01 02:30").astype("datetime64[ns]")]
 vis_counts_exp = xr.DataArray(
@@ -124,7 +124,7 @@
     },
     attrs=attrs_exp
 )
-acq_time_ir_wv_exp = [np.datetime64("1970-01-01 00:30").astype("datetime64[ns]"),
+acq_time_ir_wv_exp = [np.datetime64("NaT").astype("datetime64[ns]"),
                       np.datetime64("1970-01-01 02:30").astype("datetime64[ns]")]
 wv_counts_exp = xr.DataArray(
     np.array(
@@ -272,51 +272,60 @@
             dtype=np.uint8
         )
     )
-    time = np.arange(4) * 60 * 60 * 1e9
-    time = time.astype("datetime64[ns]").reshape(2, 2)
+    time = np.arange(4) * 60 * 60
+    timeFillValue=4294967295
+    timeAddOffset=0
+    time[0] = timeFillValue
+    time[1] = timeFillValue
+    time = time.reshape(2,2)
+
     ds = xr.Dataset(
         data_vars={
             "count_vis": (("y", "x"), count_vis),
             "count_wv": (("y_ir_wv", "x_ir_wv"), count_wv),
             "count_ir": (("y_ir_wv", "x_ir_wv"), count_ir),
             "toa_bidirectional_reflectance_vis": vis_refl_exp / 100,
             "u_independent_toa_bidirectional_reflectance": u_vis_refl_exp / 100,
             "quality_pixel_bitmask": (("y", "x"), mask),
             "solar_zenith_angle": (("y_tie", "x_tie"), sza),
             "time_ir_wv": (("y_ir_wv", "x_ir_wv"), time),
             "a_ir": -5.0,
             "b_ir": 1.0,
             "bt_a_ir": 10.0,
             "bt_b_ir": -1000.0,
             "a_wv": -0.5,
             "b_wv": 0.05,
             "bt_a_wv": 10.0,
             "bt_b_wv": -2000.0,
             "years_since_launch": 20.0,
             "a0_vis": 1.0,
             "a1_vis": 0.01,
             "a2_vis": -0.0001,
             "mean_count_space_vis": 1.0,
             "distance_sun_earth": 1.0,
             "solar_irradiance_vis": 650.0,
             "sub_satellite_longitude_start": 57.1,
             "sub_satellite_longitude_end": np.nan,
             "sub_satellite_latitude_start": np.nan,
             "sub_satellite_latitude_end": 0.1,
         },
         coords={
             "y": [1, 2, 3, 4],
             "x": [1, 2, 3, 4],
             "y_ir_wv": [1, 2],
             "x_ir_wv": [1, 2],
             "y_tie": [1, 2],
             "x_tie": [1, 2]
 
         },
         attrs={"foo": "bar"}
     )
     ds["count_ir"].attrs["ancillary_variables"] = "a_ir b_ir"
     ds["count_wv"].attrs["ancillary_variables"] = "a_wv b_wv"
+
+    ds["time_ir_wv"].attrs["_FillValue"] = timeFillValue
+    ds["time_ir_wv"].attrs["add_offset"] = timeAddOffset
+
     return ds