GP fit for data sample with absolute magnitude cuts 2 < M_G ≤ 3. Each panel corresponds to a 100-by-100 pc area cell in the (X, Y)-plane, labelled by indices i and j according to Eq. (6), thus centred on (X, Y) = (200, −600) pc. The horizontal and vertical axes show height with respect to the Sun and the normalised stellar number count as defined in Eq. (8). The solid lines correspond to the GP fits, with a smooth shaded region signifying its dispersion (mostly too small to see by eye). The jagged shaded region corresponds to the 1σ band of the data number count. The axis ranges are the same for all panels.