Main panels (from top to bottom): as functions of stellar mass, tidal strength estimation of the LSS (Q_LSS), the projected density estimation of the LSS ( η_k,LSS), and the distance to the fifth nearest neighbor galaxy out to 5 Mpc (d_5N). Green dots and gray squares correspond to isolated E galaxies from the SIG and L16 samples, respectively; the total number of galaxies is indicated in each panel. The blue, SF isolated ellipticals of SIG sample and L16 sample are shown as magenta stars and magenta triangles, respectively. Top left panel: normalized density distribution of stellar mass for SIG galaxies (green solid histogram) and L16 galaxies (black open histogram) with estimated Q_LSS values. Right panels (from top to bottom): normalized density distributions of Q_LSS, η_k,LSS, and d_5N environmental parameters for SIG galaxies (green solid histogram) and L16 galaxies (black open histogram). The integral of each histogram sums to unity.