Calculate emission rates based on a sequence of connected lines or preferably a semi-circle drawn around edifice (total line doesn't include ICA defined as "old")).

[tpering]

This section of code in figure_analysis.py is important as it defines which lines are included in the "total" line emission rate outputs. Currently whichever line is selected as the "old" line is not included in the total emissions calculated at the end. This is a reasonable approach for when cross-correlation is run but could but erroneously misinterpreted if not using cross-correlation and seeking to capture emission rates around the volcano - particularly a nice conical one. At the moment this isn't clear in the GUI (a warning somewhere would be good), however, a longer term and better solution would be to allow the drawing of a semi-circular ICA line (PCS) to capture such variation. For instance, you could allow the drawing of two semi-circles at different distances from the plume to perform cross-correlation on Line 1 and Line 2.

`# Set the young cross-correlation line (this line is not excluded from the total emission rate calculation -

only the old cross-correlation line is) It is therefore assumed that this young line is part of the set of

    # line that constrain the volcanic edifice in all directions
    if self.xcorr_ica_young > 0:
        self.pyplis_worker.cross_corr_lines['young'] = self.PCS_lines_list[self.xcorr_ica_young - 1]
    else:
        self.pyplis_worker.cross_corr_lines['young'] = None

    # Update lines (will get error on start up as fig_series isn't yet assigned. After this it works fine)
    try:
        self.fig_series.update_lines()
    except AttributeError:
        pass`