feat(transform): no-op elevation vis weights if the dataset exists

draco/analysis/transform.py

@@ -506,17 +506,21 @@ def process(self, data: containers.HybridVisStream):
         data
             Input container with different weights dataset
         """
-        weights = data.weight[:].local_array
-
-        # Remove the reference to the vis_weight dataset
-        del data["vis_weight"]
-
-        # Add the new elevation-dependent weight dataset
-        data.add_dataset("elevation_vis_weight")
+        data.redistribute("freq")
 
-        # Write the weights into the new dataset, broadcasting over
-        # the elevation axis
-        data.weight[:].local_array[:] = weights[..., np.newaxis, :]
+        # if elevation-dependent weights alread exist, this
+        # should be a no-op and just pass the dataset along
+        if "elevation_vis_weight" in data:
+            self.log.debug("Container already has the required dataset.")
+        else:
+            weights = data["vis_weight"][:].local_array
+            # Remove the reference to the vis_weight dataset
+            del data["vis_weight"]
+            # Add the new elevation-dependent weight dataset
+            data.add_dataset("elevation_vis_weight")
+            # Write the weights into the new dataset, broadcasting over
+            # the elevation axis
+            data.weight[:].local_array[:] = weights[..., np.newaxis, :]
 
         return data