Position-velocity diagrams of NGC 3198 along the major axis, considering a position angle of 213°: observed (black) and modelled (left and middle panel: red; right panel: green), derived using the steps outlined in Sect. 4. Left: without lagging extraplanar gas. Middle: with a single 1 kpc thick disk with a lag. Right: with a separate disk of lagging extraplanar gas. Contours are −0.3, 0.3 (~1.5σ), 3, and 30 mJy beam^-1. The cross indicates the galaxy centre.