 More complicated forms of data include marked point sets and spatial time series.The coordinate-wise mean of a point set is the centroid, which solves the same variational problem in the plane (or higher-dimensional Euclidean space) that the familiar average solves on the real line — that is, the centroid has the smallest possible average squared distance to all points in the set.Dispersion captures the degree to which points in a point set are separated from each other.