Histograms of the deviation angle between the true arrival direction of UHECRs and the one obtained by backtracking through the magnetic field, as reconstructed using local data sampled at three different mean rates k_sample = (600 pc)⁻¹, (425 pc)⁻¹, and (300 pc)⁻¹ (blue). For each mean sampling rate, we considered 100 independent GMFs. The observed arrival direction, the charge, and lab-frame energy were assumed to be known and are (0,0,− 1)^T, +e, and 5 × 10¹⁹ eV, respectively. The turbulent-to-uniform magnitude ratio (Eq. (10)) was set at λ = 0.2. For reference, we also plot the same angle by completely neglecting the effect of the GMF on the particle’s trajectory (red). It can be seen that local and homogeneously distributed GMF data significantly improve our estimate of the true arrival directions of UHECRs, and that there is successive improvement as k_sample becomes larger, as expected.