Plot the radiance o-b/o-a layer on same plot

[xyzemc]

create the figure to plot the O-B and O-A overlaid.

[xyzemc]

The basic function was created to plot layered histogram for omb vs oma. But only work for radiance at this moment.
The example plots attached here:

[xyzemc]

code was updated to enable plot the smooth line.