The Veilleux & Osterbrock (1987) line-ratio diagnostic diagrams of NGC 2915. Each point represents one spaxel and color-coded by the galactocentric radius. The dashed curve in the first panel is the boundary between empirical pure H II region emission and “composite” emission proposed by Kauffmann et al. (2003). The solid curves in the three panels are the Kewley et al. (2001) maximum starburst line. The gray straight lines in the middle and right panels are the empirical boundary between Seyferts and LI(N)ERs proposed by Kewley et al. (2006). The model grids are the MAPPINGS III shock (solid grids) and shock+precursor (dashed grids) models from (Allen et al. 2008) for a SMC-like metallicity. The grid lines are color-coded according to shock velocity v_s and magnetic field B.