Abstract: A method for transforming multi-dimensional data points into 1-dimensional values which are stored in a 1-dimensional index structure is disclosed. The data space is divided into a first plurality of pyramids each having a center point of the data space as a top and a (d-1) dimensional surface of the data space as a base, wherein the first plurality of pyramids is equal to twice the number of dimensions of the data space. Each pyramid is then divided into a second plurality of partitions. A Pyramid-value for each partition is then computed. Finally, each partition is stored in the index structure using the Pyramid-value as an index key.