Left – Distribution onto the Galactic plane of Cepheids with accurate iron abundances. Symbols and colors are the same as in Fig. 2. The size of the circles scales with their iron abundances (see labeled values). The bulge fields were not plotted, since we lack individual distances. The dashed lines display the position of the Sun, while the cross the position of the Galactic center. Right – Metallicity distribution of the Cepheids in the four quadrants. The solid black line shows the histogram (bin size  =  0.15 dex). The dotted red line shows the smoothed metallicity distribution estimated running a Gaussian kernel with fixed σ = 0.1 dex. The adopted dispersion accounts for errors on abundances and uncertainties in the different samples. The number of Cepheids, the mean and the σ of the Gaussian fit are also labeled.