k-means clusters for Stokes V profiles, using 20 clusters on z-normalized Stokes V. The red line is the cluster centroid (average), and the black lines are all individual profiles assigned to the cluster. The blue line is a visual aid that denotes the position of λ₀. The bottom two rows show all the z-normalized Stokes V profiles belonging to the corresponding clusters in the two top rows, with the individual profiles stacked along the vertical axis. It should be noted that the clusters are not equally populated, so the grey-scale maps will have different densities of profiles along the vertical axis.