Plot the maginal distribution in an image sub-region compiled with a run of modified (and more general) version of clip_margdist_sub.sh. The basic input file you need for this routine is the margdist_sub table file.

clip_margdist_sub_plotter 2 N 
% cat Plot.Title
box[666:695,497:505]  X=17778.0  Peak=123000.0

This is still under construction. Initially I used a simple parabolic fit to the data to derive a center and peak value. However, due to roundoff error and other factors, the effectiveness of this approach is limited. As of late Nov2018, still workin it.