Integrated intensity (moment 0) map of the N₂H⁺ (1–0) main line centered at 93.1737699 GHz (white contours) overlaid on the integrated intensity, line velocity (moment 1), and linewidth (moment 2) maps (colors) for the main line (top panels) and the satellite line centered at 93.1762595 GHz (bottom panels). The line emission has been integrated over the velocity range 93 to 98 km s⁻¹. The white contours range from 0.2 K km s⁻¹ to 6.2 K km s⁻¹ by 1.2 K km s⁻¹. The white cross indicates the position of the dust continuum emission peak of the G31 HMC. The black dashed line in the velocity maps indicates the direction of the NE–SW velocity gradient observed in the G31 HMC in several high-density tracers at high-angular resolution (e.g., Beltrán et al. 2018). The IRAM 30m beam is shown in the lower right-hand corner of the bottom right panel.