We present complexity of the Galactic outer disc by fitting the stellar volume densities of the red giant branch stars with a two-disc component model . The discs are confirmed to extend to R \sim 19 kpc . The radial density profile of the discs shows two breaks at R \sim 11 and \sim 14 kpc , respectively , which separate the radial profile into three segments with different scale lengths of 2.12 \pm 0.26 , 1.18 \pm 0.08 , and 2.72 kpc at R < 11 , 11 \leq R \leq 14 , and R > 14 kpc , respectively . The first break is likely due to the sudden drop in the radial profile of the thin disc , which may be an evidence of the radial migration . Beyond 14 kpc , the thick disc becomes prominent and the transition from thin to thick disc leads to the second break . This implies that the geometrically defined thick disc is more radially extended than the thin disc . This is also supported by the larger scale length of the thick disc than that of the thin disc . Meanwhile , the scale height of the thicker component increases from 0.637 _ { -0.036 } ^ { +0.056 } at R = 8 to 1.284 _ { -0.079 } ^ { +0.086 } kpc at R = 19 kpc , showing an intensive flared disc . Moreover , rich substructures are displayed in the residuals of the stellar density . Among them , the substructures D 14 + 2.0 and O 14 - 1.5 show a north-south asymmetry , which can be essentially explained by southward shifting of the thick disc . However , no significant overdensity is found for the Monoceros ring . Finally , the thick disc shows a ripple-like feature with unclear origin at 9 < R < 10.5 kpc .