The TileMatrixSet Variable Width tile matrices allow to define Discrete Global Grid Systems as defined by Topic 21 - Part 4: Axis Aligned, such as the CDB Global Grid and GNOSIS Global Grid.
Although both of these grid attempt to approximate equal area, they cannot fully qualify as a DGGS under Topic 21 - Part 1, because there is a requirement that cells of a given level are of equal area within a 1% margin.
The TileMatrixSet Variable Width tile matrices allow to define Discrete Global Grid Systems as defined by Topic 21 - Part 4: Axis Aligned, such as the CDB Global Grid and GNOSIS Global Grid.
Although both of these grid attempt to approximate equal area, they cannot fully qualify as a DGGS under Topic 21 - Part 1, because there is a requirement that cells of a given level are of equal area within a 1% margin.