Improve the to_dataarray method

pygmt/datatypes/grid.py

@@ -299,7 +299,7 @@ def to_dataarray(self) -> xr.DataArray:
             pad[2] : header.my - pad[3], pad[0] : header.mx - pad[1]
         ]
 
-        # Default dims and grid name
+        # Default dimension names and grid name
         dims, name = ("y", "x"), "z"
 
         # The x and y coordinates
@@ -308,13 +308,14 @@ def to_dataarray(self) -> xr.DataArray:
             "y": self.y[: header.n_rows],
         }
 
-        # Attrs for the coordinates
+        # Attributes for the coordinates and the data (i.e., gloabal attributes).
+        # Refer to the 'gmtnc_put_units' and 'gmtnc_get_units' functions in 'gmt_nc.c'.
         attrs = {"x": {}, "y": {}, "z": {}}
-        newdims = {"x": "x", "y": "y"}
-        for dim, nameunits in zip(
-            ("x", "y", "z"),
-            (header.x_units, header.y_units, header.z_units),
-            strict=False,
+        newdims = {"x": "x", "y": "y"}  # Map default dims to new dims
+        for dim, nameunits in (
+            ("x", header.x_units),
+            ("y", header.y_units),
+            ("z", header.z_units),
         ):
             long_name, units = _parse_nameunits(nameunits.decode())
             if long_name:
@@ -340,7 +341,7 @@ def to_dataarray(self) -> xr.DataArray:
         if grid.x[0] < grid.x[1] or grid.y[0] < grid.y[1]:
             grid = grid.sortby(list(grid.dims))
 
-        # Assign coordiante attributes
+        # Assign coordinate attributes
         for dim in dims:
             grid[dim].attrs.update(attrs[dim])
 
@@ -351,7 +352,7 @@ def to_dataarray(self) -> xr.DataArray:
             and attrs["y"].get("standard_name") == "latitude"
         ):
             gtype = 1
-        # update the dimension name
+        # Update the dimension names
         grid = grid.rename(newdims)
 
         # Set the gmt accesssor.