Convert dummpy times to timedelta

GenericMappingTools · Apr 22, 2024 · 9d12ae1 · 9d12ae1
1 parent d6eeade
commit 9d12ae1
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Showing 2 changed files with 11 additions and 9 deletions.
diff --git a/pygmt/src/x2sys_cross.py b/pygmt/src/x2sys_cross.py
@@ -229,12 +229,14 @@ def x2sys_cross(
                     vfname=vouttbl, output_type=output_type, header=2
                 )
 
-                # Convert 3rd and 4th columns to datetimes.
+                # Convert 3rd and 4th columns to datetime or timedelta.
                 # These two columns have names "t_1"/"t_2" or "i_1"/"i_2".
-                # "t_1"/"t_2" means they are datetimes and should be converted.
-                # "i_1"/"i_2" means they are dummy times (i.e., floating-point values).
-                if output_type == "pandas" and result.columns[2] == "t_1":
+                # "t_1"/"t_2" means they are absolute datetimes.
+                # "i_1"/"i_2" means they are dummy times relative to unix epoch.
+                if output_type == "pandas":
+                    t_or_i = result.columns[2][0]
+                    to_func = {"t": pd.to_datetime, "i": pd.to_timedelta}[t_or_i]
                     result[result.columns[2:4]] = result[result.columns[2:4]].apply(
-                        pd.to_datetime, unit="s"
+                        to_func, unit="s"
                     )
                 return result
diff --git a/pygmt/tests/test_x2sys_cross.py b/pygmt/tests/test_x2sys_cross.py
@@ -101,8 +101,8 @@ def test_x2sys_cross_input_dataframe_output_dataframe(tracks):
         columns = list(output.columns)
         assert columns[:6] == ["x", "y", "i_1", "i_2", "dist_1", "dist_2"]
         assert columns[6:] == ["head_1", "head_2", "vel_1", "vel_2", "z_X", "z_M"]
-        assert output.dtypes["i_1"].type == np.float64
-        assert output.dtypes["i_2"].type == np.float64
+        assert output.dtypes["i_1"].type == np.timedelta64
+        assert output.dtypes["i_2"].type == np.timedelta64
 
 
 @pytest.mark.usefixtures("mock_x2sys_home")
@@ -162,8 +162,8 @@ def test_x2sys_cross_input_dataframe_with_nan(tracks):
         columns = list(output.columns)
         assert columns[:6] == ["x", "y", "i_1", "i_2", "dist_1", "dist_2"]
         assert columns[6:] == ["head_1", "head_2", "vel_1", "vel_2", "z_X", "z_M"]
-        assert output.dtypes["i_1"].type == np.float64
-        assert output.dtypes["i_2"].type == np.float64
+        assert output.dtypes["i_1"].type == np.timedelta64
+        assert output.dtypes["i_2"].type == np.timedelta64
 
 
 @pytest.mark.usefixtures("mock_x2sys_home")