Geodesic Discrete Global Grid Systems Discrete Global Grid

1 geodesic discrete global grid systems

1.1 isea dggs
1.2 healpix
1.3 quaternary triangular mesh (qtm)

geodesic discrete global grid systems

a geodesic discrete global grid system (sometimes called geodesic grid) formed recursively sub-dividing planar or spherical polyhedra. examples of such grids include:

isea dggs

isea discrete global grids class of grids proposed researchers @ oregon state university. grid cells created regular polygons on surface of icosahedron, , inversely projected using icosahedral snyder equal area (isea) map projection form equal area cells on sphere. cells may hexagons, triangles, or quadrilaterals. multiple resolutions indicated choosing aperture, or ratio between cell areas @ consecutive resolutions. applications of isea dggs include data products generated european space agency s soil moisture , ocean salinity (smos) satellite, uses isea4h9 (aperture 4 hexagonal dggs resolution 9), , commercial software wordview, uses isea3h (aperture 3 hexagonal dggs).

healpix

the hierarchical equal area isolatitude pixelization (healpix) has equal area quadrilateral-shaped cells , developed use full-sky astrophysical data sets.

quaternary triangular mesh (qtm)

qtm has triangular-shaped cells created 4-fold recursive subdivision of spherical octahedron.