Spatial geometry of the Gaia samples in XY projection (apart from the conic sample; see Sect. 2.1.5). The Galactic centre (GC) is marked with a black point. Each Gaia sample is selected in a Solar-centred spherical shell with the inner and outer radii of d_min and d_max from Table 1 (see columns d₃ and d₆ for the full samples and kinematic subsamples, respectively). Additionally, only stars belonging to the local annulus R_⊙ ± ΔR with R = 8.2 kpc and ΔR = 150 pc are taken into consideration (thick grey arcs).