A DGGS must have a method of uniquely addressing each cell. Hierarchybased, spacefilling curves, and axes methods of indexing can be used. The type of tessellation can limit the choices of indexing while the type of indexing chosen can be exploited to expose useful capabilities. Indices can provide arithmetic neighbor operations, fast linear ordering, parentchild relationships, efficient cell/tree traversal, and implied spatial tiling. Mappings between the two indexing methods is often straight forward when their DGGS models are isomorphic.
a) HEALPix DGGS indexing  Landcare New Zealand b) QTM indexing  Geoffry Dutton Spatial FX c) the PYXIS innovation index
