and

A three-dimensional, multilateral data structure based on Morton sequencing, two-dimen sional run-length encoding, and Dutton's Quaternary Triangular Mesh (QTM) was devel oped, implemented and assessed. This data structure, called the Triangulated Quadtree Sequence, or TQS, was developed to map a global raster dataset onto the surface of a three dimensional solid octahedron. TQS provides the means to translate from Morton Codes to QTM and to TQS structures. To implement the triangulated quadtree sequence, a modified interrupted Collignon map projection was developed to project the world into eight equilat eral triangular facets. To assess the TQS, the regular latitude/longitude grid of the land por tion of the ETOP05 global relief database was translated and compressed into the TQS triangular lattice. The validity and usefulness of the model is assessed, and its potential uses discussed