Digital earth framework and indexing schema to extend any 'surface' Discrete Global Grid System to construct interoperable 'volumetric' Discrete Global Grid Systems

摘要

A digital Earth framework and associated indexing schema that enables a given two-dimensional polyhedral representation of the Earth's surface, (a "surface" Discrete Global Grid System (DGGS)), to be extended to construct a three-dimensional "volumetric" DGGS. The invention comprises extending the cells of a given "surface" DGGS tessellation in Earth Centred Earth Fixed (ECEF) coordinates from the reference ellipsoid (e.g. WGS84) both inward to the centre of mass of the Earth and outwardly to an arbitrary outer ellipsoidal shell defined above the reference ellipsoid. The radial dimension is divided into equal-volume ellipsoidal shells that are each tessellated using a chosen "surface" DGGS. The equal-volume voxels of the "volumetric" DGGS are constructed by joining the vertices of each equal-area "surface" DGGS cell defined on successive ellipsoidal shells. Each "volumetric" DGGS voxel is referenced at its centroid using a composite indexing schema.