Hierarchical Triangular Mesh (HTM) is a kind of quad tree based on subdivision of a distorted octahedron, used for mesh generation in 3-D computer graphics and geometric data structures.
Functions
It provides a systematic indexing method for objects localized on a sphere. It is an efficient method for searching different resolutions like arc seconds or hemispheres. It can be used as a method to subdivide the spherical surface into triangles of nearly equal shape and size.
See also
HEALPix Quadrilateralized spherical cube Geodesic grid
References