OGC CIS defines coverages, that is: spatio-temporally varying phenomena; technically, this unifies (regular and irregular) grids, point clouds, and meshes. In particular, CIS is the OGC datacube standard. Multiple encodings are available, such as XML, JSON, RDF, NetCDF, GeoTIFF, GRIB2, and more. CIS is in active use, supported by a who's who of open-source and proprietary tools, both clients and servers. Official reference implementation is rasdaman.
As opposed to the companion standards ISO 19123 / OGC Abstract Topic 6, CIS stablishes concrete, interoperable coverages amenable to compliance testing, eg, in WCS.