Two dimensional stellar density map of the two working samples, namely the OB sample (left column) and the RGB sample (right column). The sizes of the bins are 0.32 kpc × 0.64 kpc for the OB sample and 0.16 kpc × 0.32 kpc for the RGB sample. We mark the Sun position with a star and the black dotted lines show circles at different Galactocentric radii, R = 8, 10, 12, 14, and 16 kpc. The colour bar is in log-scale and is the same for both panels. The Galaxy rotates clockwise.