1. A method for analysing a point cloud, the method comprising: receiving a point cloud, comprising a plurality of points, each point representing a spatial point in an image; arranging the points into a hierarchical search tree, with a lowest level comprising a plurality of leaf nodes, where each leaf node corresponds to a point of the point cloud, the search tree comprising a plurality of hierarchical levels with tree nodes in each of the hierarchical levels, the nodes being vertically connected to each other though the hierarchy by branches, wherein at least one moment of a property of the descendant nodes is stored in each tree node; and determining geometric information of the points located within a region, by identifying the highest level tree nodes where all of the descendent leaf nodes are contained within the region and selecting the leaf nodes for the points where no sub-tree is entirely contained within the region, such that the points falling within the region are represented by the smallest number of nodes and performing statistical operations on the nodes representing the points in the region, the statistical operations being determined from the moments of the properties stored within the identified tree nodes.