Position-velocity (P-V) diagram to illustrate the distribution of filament G37, obtained from ¹³CO emission. The distribution is shown along the filament skeleton, as depicted in Fig. 2, with the dense clumps C1, C2, C3, and C4 (as shown in Fig. 1) represented by the red columns. The x-axis denotes the filament length in unit as pc, while the y-axis shows the velocity, V_LSR. The diagram shows vertical dashed red lines for the locations of four dense clumps (C1–C4) and black lines for the velocity gradients. The extra velocity gradient of clump C1 is shown as a dashed line.