Spatial distribution of RGB and RC stars with 20.7 mag  < I <  24.6 mag in the northern fields. The resolution of the map is 1′   ×  1′ , smoothed with a Gaussian kernel of 5 pixels FWHM (shown at the top-right corner of the figure). The colour scale indicates the number of stars per pixel. The density contours of the Hi clouds detected in this region are overlaid as a comparison. Contours are at 3.5, 6, 8.5, 11, 13.5 × 10¹⁸ cm^-2.