Index: trunk/SDToolBox/extract_data.py
===================================================================
diff -u -r188 -r189
--- trunk/SDToolBox/extract_data.py	(.../extract_data.py)	(revision 188)
+++ trunk/SDToolBox/extract_data.py	(.../extract_data.py)	(revision 189)
@@ -435,7 +435,10 @@
                 output_values=cases_dict[OutputData.var_lon_key],
                 is_gridded=input_data.is_gridded,
             )
-            return (nn_lon_idx, nn_lat_idx), (nn_lon_values, nn_lat_values)
+            return (
+                (nn_lon_idx, nn_lat_idx),
+                (np.array(nn_lon_values), np.array(nn_lat_values)),
+            )
 
         def _set_nn(
             self,