Data structures for multilayer N-dimensional data using hierarchical structure

A multilayer (ML) data structure, which is a hierarchical data structure for N-dimensional data classified into layers, is proposed. In the ML structure, a node structure is extended so that data can be stored not only in the leaves (terminal nodes) but also in internal nodes by adding a layer-management mechanism. The creation, management, and searching methods of the ML structure are described, taking two-dimensional point data classified into layers as an object. The management of line data or expansion to n(n>2)-dimensional data can be easily realized. Good retrieval performances are obtained in the case of a spatial search for a specific layer's data and that for plural layers' data