Visual comparison of a selection of inverted parameters from spatially degraded spectra with the original data (top) for a spatially coupled inversion (middle) and a spatially uncoupled inversion (bottom). Shown are the parameter maps at the optical depths where they are most accurately determined. From left to right: temperature at τ = 1, magnetic field strength, inclination angle and azimuth angle at τ = 0.16, and the line-of-sight velocity at τ = 1. The color schemes are optimized for each quantity and have an identical but otherwise arbitrary scale for the original and inverted parameters. Tick marks indicate the spatial scale in arcseconds. Clearly visible is the difference in the accuracy of the retrieved parameters when the spatial smearing by the telescope is not taken into account.