Simplify legacy gridspec for reduced_gg

Author: sandorkertesz

src/earthkit/data/field/grib/legacy_grid_spec.py

@@ -110,6 +110,8 @@ class LegacyGridSpecMaker(dict):
     def __init__(self, metadata):
         self.conf = CONF.config
 
+        self._global = metadata.get("global", 0) == 1
+
         # remap metadata keys and get values
         d = {}
         for k, v in self.conf["grib_key_map"].items():
@@ -146,7 +148,10 @@ def make(self):
             for k in self.conf["rotation_keys"]:
                 d.pop(k, None)
 
-            # only canonical scanning mode is supported
+        if d.get("type", None) == "reduced_gg" and self._global:
+            d.pop("area", None)
+
+        # only canonical scanning mode is supported
         for k in list(d.keys()):
             if k == "j_points_consecutive":
                 if d[k] != 0:

tests/data/gridspec/reduced_gg.yaml

@@ -26,11 +26,11 @@
     longitudeOfLastGridPointInDegrees: -70.0
 - file: reduced_gg/t_reduced_gg_O128_global.grib1
   gridspec:
-    area:
-    - 89.463
-    - 0.0
-    - -89.463
-    - 359.319
+    # area:
+    # - 89.463
+    # - 0.0
+    # - -89.463
+    # - 359.319
     grid: O128
     i_scans_negatively: 0
     j_points_consecutive: 0

tests/grib/test_grib_gridspec.py

@@ -22,6 +22,10 @@
 from earthkit.data.utils.testing import earthkit_remote_test_data_file
 from earthkit.data.utils.testing import earthkit_test_data_file
 
+# TODO: all the se tests are for the legacy gridspec. We should add tests for the
+# new one from eckit.geo as well, and then remove the legacy one.
+
+
 SUPPORTED_GRID_TYPES = [
     "sh",
     "regular_ll",
@@ -88,6 +92,7 @@ def test_grib_gridspec_from_metadata_valid(metadata, ref, name):
         pytest.skip()
 
     ref = ref.copy()
+
     for k in ["type", "i_scans_negatively", "j_points_consecutive", "j_scans_positively"]:
         ref.pop(k, None)