Fix rounding in grib resolution (#404)

Author: sandorkertesz

src/earthkit/data/readers/grib/metadata.py

@@ -147,9 +147,11 @@ def resolution(self):
         if grid_type in ("reduced_gg", "reduced_rotated_gg"):
             return self.metadata.get("gridName")
 
-        if grid_type == "regular_ll":
+        if grid_type in ("regular_ll", "rotated_ll"):
             x = self.metadata.get("DxInDegrees")
             y = self.metadata.get("DyInDegrees")
+            x = round(x * 1_000_000) / 1_000_000
+            y = round(y * 1_000_000) / 1_000_000
             assert x == y, (x, y)
             return x
 

tests/grib/test_grib_geography.py

@@ -229,6 +229,7 @@ def test_grib_projection_mercator(fl_type, array_backend):
         (earthkit_examples_file("test.grib"), 4.0),
         (earthkit_test_data_file("rgg_small_subarea_cellarea_ref.grib"), "O1280"),
         (earthkit_test_data_file("rotated_N32_subarea.grib"), "N32"),
+        (earthkit_test_data_file("rotated_wind_20x20.grib"), 20),
     ],
 )
 def test_grib_resolution(path, expected_value):