Velocity field in the case of H I filaments derived for data with a 1 km s⁻¹ channel width at an arbitrarily selected central position, l = 160°, b = 30° in gnomonic projection. The field size is 27. °7; only velocities in the range − 30 < v_LSR < 30 km s⁻¹ are displayed. Top: velocities from original telescope data. Bottom: results derived after simulating a noise amplification by a factor of N_f = 4.