An index to a plurality of entities is built, where each entity is represented by a point defined in a space. Entities whose points are furthest apart are identified. A first area is created, the extremities of which first area are given by the points representing the identified entities. Entities falling within the first area are assigned to a storage area corresponding to the first area. The first area is divided into a plurality of second areas. For each of the plurality of second areas, a. each of the plurality of second areas is linked to the first area, and, b. the above steps are repeated until the first area includes a single point. Storage areas corresponding to each of the first area are then written to the index.