Maps of Stokes intensity and magnetic field components for ROI 1. The ROI has been rotated by 90° counter-clockwise to allow for an identical layout as Figs. 7, A.1, and A.3. The first eight columns contain the Stokes I, Q, U, and V intensity maps, where each column pair first shows the observed and then the synthetic maps, clipped to the same values. The Stokes I map is taken at Ca II 8542 Å line centre, while the other Stokes components are shown at Δλ = +0.21 Å offset. The remaining nine columns contain the magnetic field components B_∥, B_⊥, and azimuth φ, where each column triple shows the MHS, WFA, and non-LTE inversion result from left to right, again clipped to the same values. The non-LTE magnetic field components are the average over log τ₅₀₀ = [ − 5.1, −4.1], and the MHS field components are averaged over the equivalent z-height (determined per pixel). The contours highlight regions in which the WFA-derived B_⊥ transitions 150 G (solid) and 350 G (dashed). The tick spacing is the same for the x- and y-axes.