Distribution of emission-line ratios as a function of the Hα flux, also tracing the local Hα flux surface brightness. The blue, resp. red, points correspond to those located inside, resp. outside, the starburst locus in the [OI]/Hα BPT diagnostic diagram (see Fig. 7). The small black points correspond to spaxels with an undetected [OI] line. The error bars are 1σ typical dispersion, and their y-axis position is the mean value of the ratio in the given Hα flux range.