Number of red giants per square degree as a function of Galactic longitude and distance for fields with b = 0°. To increase contrast, the plotted quantity is the square root of this number, N^1/2. The white dashed line represents the completeness limit at each line-of-sight. The blue and red dashed lines mark the place of a 45° bar and a ring of r = 4.5   kpc, respectively. The sudden drop at l = −8° is due to the combination of higher reddening and stellar density. All these giants verify |b| ≤ 0.5°.