All the galaxies where SFR and mass have been measured in the redshift bin 0.092 <  z <  0.093. The red crosses are individual galaxies while the green circle shows the point of highest density and the blue line shows our rough fit of the density ridge. It can clearly be seen that there is an overdensity along the solid blue line. By inspection it can also be seen that there is another overdensity around −0.8 SFR ranging from 10^10.8 M_⊙ to about 10^11.1 M_⊙. We make 199 lines that are parallel to the green one and measure overdensities along them to identify where the centre of the ridge is. By combining all these 200 measurements we can get a good idea of where the ridges are. The angle of the green line to the ridge has been optimized such that we have the smallest variance across all the redshift bins.