From 63169082177784cb5c31f3e050571e7b1f662300 Mon Sep 17 00:00:00 2001
From: Deepak Chandan <deepak.chandan@me.com>
Date: Thu, 22 Feb 2024 19:24:07 -0500
Subject: [PATCH] infer units and description of some auxiliary variables

---
 STACpopulator/extensions/datacube.py | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/STACpopulator/extensions/datacube.py b/STACpopulator/extensions/datacube.py
index 5f452b3..a98f9aa 100644
--- a/STACpopulator/extensions/datacube.py
+++ b/STACpopulator/extensions/datacube.py
@@ -169,10 +169,8 @@ def dimensions(self) -> dict[str, Dimension]:
                             properties = dict(
                                 type=type_.value,
                                 extent=extent,
-                                description=v.get(
-                                    "description",
-                                    v.get("long_name", criteria["standard_name"][0])
-                                ) or "",
+                                description=v.get("description", v.get("long_name", criteria["standard_name"][0]))
+                                or "",
                             )
                             if type_ == DimensionType.SPATIAL:
                                 properties["axis"] = axis
@@ -197,6 +195,8 @@ def variables(self) -> dict[str, Variable]:
                 # Some variables like "time_bnds" in some model files do not have any attributes.
                 attrs = {}
 
+            self._infer_variable_units_description(name, attrs)
+
             variables[name] = Variable(
                 properties=dict(
                     dimensions=meta["shape"],
@@ -207,6 +207,25 @@ def variables(self) -> dict[str, Variable]:
             )
         return variables
 
+    def _infer_variable_units_description(self, name, attrs):
+        """Try to infer the units and description of some simple coordinate variables."""
+        if name == "time_bnds":
+            related_variable = "time"
+            attrs["description"] = "bounds for the time coordinate"
+        elif name == "lat_bnds":
+            related_variable = "lat"
+            attrs["description"] = "bounds for the latitude coordinate"
+        elif name == "lon_bnds":
+            related_variable = "lon"
+            attrs["description"] = "bounds for the longitude coordinate"
+        else:
+            return
+
+        try:
+            attrs["units"] = self.attrs["variables"][related_variable]["attributes"]["units"]
+        except KeyError:
+            pass
+
     def is_coordinate(self, attrs: MutableMapping[str, Any]) -> bool:
         """Return whether variable is a coordinate."""
         for key, criteria in self.coordinate_criteria.items():