Spectra for selected LOS with strong inflow motions. The first frame shows the inflow index ξ convolved to 1″ resolution. Crosses mark five locations with large ξ values, and the plots on the right show spectra for these positions (rows in decreasing order of latitude). Spectra in the first column correspond to ideal observations and the spectra in the second column to simulated ngVLA observations. Spectra are plotted for C¹⁸O (black lines), HCO⁺ (blue), H¹³CO⁺ (cyan), and N₂H⁺ (dashed red lines).