Sample distribution in the [Mg/Fe] vs. [Fe/H] plane. Upper right panel: whole working sample (gray points). A fiducial median profile and 1σ dispersion band is constructed over several metallicity bins. Remaining panels: individual field distributions (green points) and fiducial profile and dispersion band of the whole working sample (red line and shaded area). The number of stars is given in parentheses. The order of the panels approximately indicates the positions of fields in the (l,b) plane.