👌 Handle pandas.Series in deltatime_to_utc_time conversion

Patches #40. The deltatime_to_utctime converter didn't handle pandas.Series properly, as the start_epoch variable would have an index of 0, and the datetime + timedelta operation would only get applied at index 0 instead of along the whole column. Calling squeeze() converts the pandas.Series to a pandas.Timestamp, so that the addition operation is broadcast to the whole column. This also works on an xarray.DataArray and numpy.array. Doesn't work for a dask.Series, but we can work that out when the need arises.

deepicedrain/spatiotemporal.py

@@ -99,7 +99,9 @@ def deltatime_to_utctime(
     Note, does not account for leap seconds! There are none declared since the
     last one announced on 31/12/2016, so it should be fine for now as of 2020.
     """
-    utc_time: xr.DataArray = dataarray.__class__(start_epoch) + dataarray
+    start_epoch = dataarray.__class__(start_epoch).squeeze()
+
+    utc_time: xr.DataArray = start_epoch + dataarray
 
     return utc_time
 

deepicedrain/tests/test_spatiotemporal_conversions.py

@@ -12,10 +12,39 @@
 from deepicedrain import catalog, deltatime_to_utctime, lonlat_to_xy
 
 
-def test_deltatime_to_utctime():
+def test_deltatime_to_utctime_pandas_series():
     """
-    Test that converting from ICESat-2 delta_time to utc_time works,
-    and that the xarray dimensions are preserved in the process.
+    Test that converting from ICESat-2 delta_time to utc_time works on a
+    dask.dataframe.core.Series.
+    """
+    atl11_dataset: xr.Dataset = catalog.test_data.atl11_test_case.to_dask()
+    atl11_dataframe: pd.DataFrame = atl11_dataset.to_dataframe()
+
+    utc_time: pd.Series = deltatime_to_utctime(dataarray=atl11_dataframe.delta_time)
+
+    assert utc_time.shape == (2808,)
+
+    npt.assert_equal(
+        actual=utc_time.min(), desired=pd.Timestamp("2019-05-19T20:53:51.039891534"),
+    )
+
+    npt.assert_equal(
+        actual=utc_time.loc[3].mean(),
+        desired=pd.Timestamp("2019-05-19 20:54:00.925868800"),
+    )
+    npt.assert_equal(
+        actual=utc_time.loc[4].mean(),
+        desired=pd.Timestamp("2019-08-18 16:33:47.791226368"),
+    )
+    npt.assert_equal(
+        actual=utc_time.max(), desired=pd.Timestamp("2019-08-18T16:33:57.834610209"),
+    )
+
+
+def test_deltatime_to_utctime_xarray_dataarray():
+    """
+    Test that converting from ICESat-2 delta_time to utc_time works on an
+    xarray.DataArray, and that the dimensions are preserved in the process.
     """
     atl11_dataset: xr.Dataset = catalog.test_data.atl11_test_case.to_dask()