Separate operator to calculate power spectra #1871
Description
What problem does your feature request solve?
The power spectra is currently calculated and plotted in the main plot.py operator. However, this method does not allow aggregation of the power spectra (e.g. mean). If the power spectra are calculated in a separate operator rather than in plot.py and the resulting power spectra plotted using the line series method in plot.py, aggregation will be possible using the collapse operator.
Describe the solution you'd like
Move the existing functions and code for calculating the power spectra into a separate operator, remove the existing code and adjust the line series plotting code to allow for line plotting other than timeseries.
Describe alternatives you've considered
This is the simplest solution.