(a) Column density extracted from PPMAP. The white dotted contours indicate the ¹³CO moment 0 map integrated from 47 to 64 km s⁻¹ with contour levels from 16 (3σ) to 56 K km s⁻¹ in steps of 8 K km s⁻¹ . The red open circles and black open triangles indicate the Class I and Class II YSOs identified in Section 3.2, respectively. The black squares indicate the ATLASGAL clumps. (b) Column density estimated from ¹³CO. The massive star formation signatures (6.7 GHz masers, MSX sources, and H II regions) are drawn in the same manner as in Figure 2. (c) Dust temperature extracted from PPMAP. (d) FUV field. The contour levels at G₀ =  300, 500, 1000, and 3000 are drawn. The dashed lines in panels (b) and (d) divide the R1 region into four main clouds, namely, Clouds 1–4.