Complete process for redefining the S-L lines in the [S II] and [O I] BPT diagrams using the method proposed in Kewley et al. (2006). (a) shows the result of redefining the S-L line in the [S II] BPT diagram using the same method in Kewley et al. (2006). The huge red and green asterisks represent the empirical base points selected by Kewley et al. (2006) and our new selection. The small yellow asterisks represent the boundary points of the Seyferts and LINERs distributions in each sector ring. The solid red line is the Ke01 line, the dashed red line is the S-L line in the [S II] BPT diagram from Kewley et al. (2006), and the solid green line is the result of our replication of their work. The contour filled with bluish colors represents the results for the sample of our collected galaxies. The corresponding number densities of the different colors are shown in the colorbar on the right side of the panel. (b) shows the result of redefining the S-L line in the [O I] BPT diagram using the same method in Kewley et al. (2006). The symbols and line styles have the same meanings as those in panel (a). The contour filled with bluish colors represents the results for the sample of our collected galaxies. The corresponding number densities of the different colors are shown in the colorbar on the right side of the panel. (c) shows the dependence of the percentage of galaxies count within each Ke-bin in sector ring[15] relative to the total count of galaxies in the entire sector ring on the angle with the X-axis. The red arrow represents the boundary point between Seyferts and LINERs within sector ring [15]. (d) shows the dependence of the percentage of galaxies count within each Ke-bin in sector ring[9] relative to the total count of galaxies in the entire sector ring on the angle with the X-axis. The red arrow represents the boundary point between Seyferts and LINERs within sector ring [9].