Moving average [M/H] profile of GC late-type stars in several regions as a function of different photometric properties. The panels show, from top to bottom, extinction corrected K_S,0, extinction A_KS. The regions are as defined in Table 2 and shown with colours and symbols as described in the upper panel legend. The average is computed on 50 (centre), 80 (East and West), or 100 stars (surrounding and north regions), as the number of stars varies in these regions. Uncertainties of [M/H] are Poisson errors.