1. An automated method for classifying particles in at least one sample into one or more data clusters, comprising the steps of: automatically collecting a plurality of parameters for each of a plurality of particles in a sample; automatically plotting each particle on a two-dimensional scatter plot; and automatically constructing at least one geometric boundary on the two-dimensional scatter plot so as to enclose a group of the plotted particles in a data cluster, said boundary having a polygonal shape defined by a plurality of vertices and being constructed by creating at least one one-dimensional histogram from a cross-section of the two-dimensional scatter plot.