Geometry of the molecular inflow along the bar (dashed yellow line) in NGC 6860 and along one of the spiral arms in Mrk 915 (assuming that the arms are leading). The yellow elliptic cylinders have heights, h, and areas, A = πr_ar_d, where r_d is half the height of the disk and r_a is the major radius of the face (see inset in the right panel). The superscript numbers identify the regions used in calculations in Sect. E.1. The cylinders are drawn over the LoS residuals of the disk model (as Fig. 7). These residuals associated with components used in the Ṁ_mol,in calculations: c1 for NGC 6860 and c2 for Mrk 915. The reddish-purple and blue dashed ellipses delimit the regions used to obtain the velocities and masses of the inflows coming from the north and the south in NGC 6860. For Mrk 915, they mark the region of the farthest and the nearest inflowing clumps.