Figure 3.

Example of class selection from a self-organizing map of rotational spectra. The user interactively identifies distinct classes, each of which may comprehend several (neighboring) code vectors. In this example, two classes were identified, one with sixfold symmetry and one with threefold symmetry. Code vectors were identified as belonging to the sixfold symmetric class when they contained a single peak at the sixfold harmonic. Code vectors were identified to belong to the threefold symmetric class when they contained the largest peak at the threefold harmonic and a secondary peak at the sixfold harmonic. The graphical interface of the xmipp_show program (Steps 14 and 20) allows calculating averages for all experimental measurements corresponding to the selected classes (insets).