(n + 1)³ combinations of best fits on the inner and outer scale-lengths with minimal standard deviation, for FCC179 (here n = 2). range_in is represented with a red spline, and range_out is represented with a cyan spline. model_rangein is marked in orange, while model_rangeout is marked in green. The break radius is marked at the intersecting point. Rms residuals, errors of the intercept, and slope of the fitted models for the inner and outer discs are mentioned in each plot.