Ensure survey dates are saved in correct order

survey_tools.py

@@ -143,7 +143,7 @@ def update_survey_output(df, output_dir):
         output_dir:  directory where csv files are saved
 
     Returns:
-        None
+        True if current survey is latest, otherwise False
     """
     # Merge current survey with existing data
     profiles = df['Profile'].unique()
@@ -168,5 +168,10 @@ def update_survey_output(df, output_dir):
         except FileExistsError:
             pass
 
+        # Ensure survey dates are in correct order
+        elev_cols = sorted([col for col in master.columns if 'Elevation' in col])
+        other_cols = [col for col in master.columns if 'Elevation' not in col]
+        master = master[other_cols + elev_cols]
+
         # Export updated results
         master.to_csv(csv_name, index=False)