From 756349966b855986aad31266b90b7829e55fc696 Mon Sep 17 00:00:00 2001
From: Nada Akkari <akkarinada8@gmail.com>
Date: Mon, 15 Dec 2025 15:14:43 +0100
Subject: [PATCH 1/2] First draft of the process to check and ensure all
 variables have a unit of measurement across all the workflow.

---
 src/medunda/tools/units.py | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 src/medunda/tools/units.py

diff --git a/src/medunda/tools/units.py b/src/medunda/tools/units.py
new file mode 100644
index 0000000..007cbda
--- /dev/null
+++ b/src/medunda/tools/units.py
@@ -0,0 +1,22 @@
+import logging
+
+from medunda.components.dataset import Dataset
+from medunda.plotter import VAR_METADATA
+
+logger = logging.getLogger(__name__)
+
+
+def check_units(ds: Dataset, fill_from_metadata: bool = True):
+    for var_name in ds.data_vars:
+        var = ds[var_name]
+        units = ds.attrs.get("units", None)
+
+        if units is None and fill_from_metadata:
+            unit_meta = VAR_METADATA.get(var_name, {}).get("unit")
+            if unit_meta:
+                var.attrs["units"] = unit_meta
+                logger.warning(
+                    f"Variable {var_name} have no unit so it is filled from VAR_METADATA"
+                )
+            else:
+                raise ValueError(f"Variable {var_name} has no units")

From bebd86959694f7c20dbb0e4ff0286609c1fd558c Mon Sep 17 00:00:00 2001
From: Nada Akkari <akkarinada8@gmail.com>
Date: Mon, 15 Dec 2025 15:17:50 +0100
Subject: [PATCH 2/2] Unit correction

---
 src/medunda/plotter.py     |  2 +-
 src/medunda/tools/units.py | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/medunda/plotter.py b/src/medunda/plotter.py
index 8079923..55c6250 100644
--- a/src/medunda/plotter.py
+++ b/src/medunda/plotter.py
@@ -13,7 +13,7 @@
 LOGGER = logging.getLogger(__name__)
 
 VAR_METADATA = {
-    "o2": {"label": "Oxygen", "unit": "µmol/m³", "cmap": cmocean.cm.deep},  # pyright: ignore[reportAttributeAccessIssue]
+    "o2": {"label": "Oxygen", "unit": "mmol/m³", "cmap": cmocean.cm.deep},  # pyright: ignore[reportAttributeAccessIssue]
     "chl": {
         "label": "Chlorophyll-a",
         "unit": "mg/m³",
diff --git a/src/medunda/tools/units.py b/src/medunda/tools/units.py
index 007cbda..6450d9a 100644
--- a/src/medunda/tools/units.py
+++ b/src/medunda/tools/units.py
@@ -6,6 +6,19 @@
 logger = logging.getLogger(__name__)
 
 
+def check_variable_units(var):
+    """
+    Check if a single variable has a "unit" attribute.
+    """
+    var_name = var.name
+    units = var.attrs.get("units")
+    result = {
+        "variable": var_name,
+        "units": units,
+    }
+    return result
+
+
 def check_units(ds: Dataset, fill_from_metadata: bool = True):
     for var_name in ds.data_vars:
         var = ds[var_name]
@@ -20,3 +33,9 @@ def check_units(ds: Dataset, fill_from_metadata: bool = True):
                 )
             else:
                 raise ValueError(f"Variable {var_name} has no units")
+
+
+def check_file_units():
+    """Open a NetCDF file and check the presence of a variable.
+    If a unit is missing, it fills it from VAR_METADATA."""
+    pass