get_time_coord

ethograph.utils.xr_utils.get_time_coord(da)

Return the time coordinate of a DataArray, regardless of its name.

Every feature variable in an ethograph dataset must have at least one dimension whose name contains "time" (e.g. time, time_aux, time_labels). Different features can use different time dimensions at different sampling rates — this function finds the right one for a given DataArray. See Data Format Requirements for the full specification.

Lookup order: dimension coordinates (da.dims) are checked before non-dimension coordinates (da.coords), so the primary time axis that actually indexes the data is returned even when a shorter auxiliary coordinate is also attached.

Parameters:

da (xarray.DataArray) – Any DataArray from an ethograph dataset.

Returns:

The time coordinate values, or None if no coordinate name contains "time".

Return type:

xarray.DataArray or None

Examples

>>> import ethograph as eto
>>> dt = eto.open("experiment.nc")
>>> ds = dt.itrial(0)

Feature with the default time dimension:

>>> eto.get_time_coord(ds["speed"])
<xarray.DataArray 'time' (time: 9000)> ...

Audio stored on a higher-rate time_aux axis:

>>> eto.get_time_coord(ds["audio_waveform"])
<xarray.DataArray 'time_aux' (time_aux: 441000)> ...

Used internally by add_changepoints_to_ds to discover which time dimension to vectorise over.