Top: robust standard deviation of the metallicity in logarithmically spaced radial bins. Bottom: Anisotropy parameter (Equation (4)) quantifying the importance of azimuthal variations in the scatter of metallicity at a given radius. A valuer χ ≈ 0 indicates an isotropic scatter. The colors are as in Figure 2. The differences in the radial extents of the two quantities are caused by low number statistics in the outer galaxy, which forbids the azimuthal binning necessary to compute χ.