TimeSeriesDict plotting does not work as expected

Created by: rutujagurav

The TimeSeriesDict plot() function is convenient and has several options like sharex and separate. But I have found that they don't work as expected. Consider the following example code -

from gwpy.timeseries import TimeSeries, TimeSeriesDict
from gwpy.time import to_gps, from_gps
from gwpy.plot import Plot

start_gps = to_gps('2020-01-04T00:00:00')
end_gps = to_gps('2020-01-4T01:00:00')
example_chs = ['L1:ISI-GND_STS_ETMX_X_BLRMS_30M_100M.rms,s-trend', 'L1:ISI-GND_STS_ETMX_X_BLRMS_100M_300M.rms,s-trend', 'L1:ISI-GND_STS_ETMX_X_BLRMS_1_3.rms,s-trend']
data = TimeSeriesDict.get(example_chs, start=start_gps, end=end_gps, allow_tape=True)

plot = data.plot(label='key', separate=True, sharex=True)
plot.legend()
plot.show()

The output plot does not make separate plots for each item of the dictionary (i.e. each channel) -

It's the same result if you use the Plot() function instead as I believe the data.plot() is using Plot() under the hood.

plot = Plot(data, sharex=True, separate=True)
plot.show()

If you instead run the following code, you get the expected outcome of separate and sharex set to True but the plots are empty.

plot = Plot(*data, sharex=True, separate=True)
plot.show()

If you run the following code, you get the right plots and separate and sharex work as expected but there is not way to satisfactorily add an unambiguous legend or title to the subplots to identify them by the channel name.

plot = Plot(*[value for key, value in data.items()], sharex=True, separate=True)
plot.legend(list(data.keys()))
plot.show()

The expected behavior of setting sharex and separate to True for a TimeSeriesDict is a figure with subplots corresponding to the timeseries of each item in the dict where each subplot is identified (via a legend or title) with the channel name. If the legend for the separate subplots is going to be combined like in the last plot above, then the subplots need to be different colors.

My GwPy version is 3.0.2