(Top) Spatial profiles of normalized emission line intensities observed in the Horsehead nebula, compared with predictions from a Meudon PDR model with P_th = 4 × 10⁶ K cm⁻³ and G₀ = 100, wrapped in a locally spherical cloud with a curvature radius R_C = 0.05 pc. These conditions correspond to commonly adopted literature values. The left panels show the raw profiles from the wrapping procedure, while the right panels present the same profiles convolved to the native angular resolution of each tracer. In those figures, the radiation field comes from the right. (Bottom) Observed maximum intensities of various tracers (colored crosses) compared to model predictions (circles with error bars). All tracers are well reproduced, except for H₂O, where the model overestimates the observed maximum intensity by an order of magnitude.