[N II]/[O II] vs. [N II]/Hα for all spaxels in the strong-line sample. Instead of a narrow sequence, there is noticeable scatter in this relation. The two blue dashed lines separate the spaxels into high, mid, and low [N II]/Hα bins. The data is meshed into 100 × 100 bins. The grayscale represents the density of all selected spaxels in each bin, while the orange contours enclose 68%, 95%, and 99% of the spaxels. The blue error bars in the top left corner denote the typical 1σ uncertainty of the line ratios. The extinction vector is given at the top right corner.