Constraining the parameters for a resolved galaxy. The black dots correspond to the line ratios of CO(J ≥ 2−1) with CO(1–0) for a pixel in the emission map. The red dots correspond to the line ratios of ¹³CO (J ≥ 2−1) with ¹³CO (1–0) for the same pixel. The green dots correspond to the line ratios of the same transitions of ¹³CO and CO for a pixel. The dashed line are the line ratios of these transitions of the best fit PDR model. The PDR models in the left column labeled “mPDR” consider a range of possible Γ_mech in the heating budget while fitting these line ratios (the dots), while the plots labeled “PDR” do not take Γ_mech into account. The labels A, B, C, and D correspond to the pixels indicated in the top panel of Fig. 8. The parameters of the best fit PDR models for each pixel are listed in Table 2.