(Top panel) Continuum-subtracted Hα image of NGC 5682, see the top-right panel caption of Fig. 7 for details. Here we show the positions of two slits. (Center panels) Flux at the Hα wavelength along the two slits, shown as a function of the distance from the SN location and from the nucleus. These positions are marked by vertical dotted lines. The N2 measurements for each H ii region are shown at the corresponding positions in the top sub-panels. For the slit at the SN position we also show the O3N2 and R23 metallicity estimates, and the E(B − V) values that we computed through the measured Balmer decrements. (Bottom panel) Metallicity gradient of NGC 5682, see the bottom-panel caption of Fig. 6 for details. We also reported the N2 metallicity from the spectrum taken by SDSS at the center of the galaxy.