Position dependence of integrated line intensities for static spherical ratran models (Sect. 4.2) of C¹⁷O, HCN, CS, C³⁴S, HCO⁺ and H¹³CO⁺. Black solid and dashed lines represent two perpendicular slice directions in the observed maps, red lines represent radial dependence of integrated line strength in the 1D static models. At the line center, the sky ray tracing routine calculates the following optical depths through the center of the model sphere: 0.095 for C¹⁷O, 33 for HCN, 10 for CS, 0.38 for C³⁴S, 34 for HCO⁺ and 0.64 for H¹³CO⁺. Abundance values (X) are presented in the form a   (b), representing a  ×  10^b.