The point samples are arranged in a hierarchic data structure in a manner such that each point sample is an end point, or leaf node, in a hierarchical tree, wherein {HEAD ~ the branch} points in {TAIL ~ the hierarchy tree} are average values of the nodes lower in the hierarchy of the tree 
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The point samples are arranged in a hierarchic data structure in a manner such that each point sample is an end point , or leaf node , in a hierarchical tree , wherein { HEAD ~ the branch } points in { TAIL ~ the hierarchy tree } are average values of the nodes lower in the hierarchy of the tree
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH