simplify 30min time shift for resample

Author: mhidas

aodntools/timeseries_products/velocity_hourly_timeseries.py

@@ -54,14 +54,14 @@ def get_resampled_values(nc_cell, ds, slice_start, varlist, binning_function, ep
     """
     df_cell = nc_cell[varlist].squeeze().to_dataframe()
     ## back the index 30min
-    df_cell.index = df_cell.index - pd.Timedelta(minutes=30)
+    df_cell.index = df_cell.index + pd.Timedelta(minutes=30)
     # TODO: shift timestamps to centre of sampling interval
 
     df_cell_1H = df_cell.resample('1H')
     slice_end = len(df_cell_1H) + slice_start
 
     ## move time it forward and get it
-    time_slice = ((np.fromiter(df_cell_1H.groups.keys(), dtype='M8[ns]') + np.timedelta64(1, 'h')) - epoch) / one_day
+    time_slice = (np.fromiter(df_cell_1H.groups.keys(), dtype='M8[ns]') - epoch) / one_day
     ds['TIME'][slice_start:slice_end] = time_slice
 
     # take the mean of the variables