January 2019 - What is a coverage, after all? This fundamental spatio-temporal data structure, encompassing (among others) datacubes, is widely used, based on adopted and implemented OGC and ISO standards like WCS. However, the conceptual foundations are outdated. This is being changed now.

On a high level it is clear: ISO 19123, which is identical to OGC Abstract Topic 6, describes the foundations of coverages. Accordingly, coverages encompass regular and irregular spatio-temporal grids, point clouds, and general meshes. However, this standard - crafted around the year 2000 - is not up-to date and needs urgent revision according to ISO and other experts. Definitions like "a raster is like a grid of pixels on a cathode ray tube" are not exactly representing modern understanding.

Therefore, ISO since several years has set up a New Work Item Proposal (NWIP) based on which project leader Prof. Liping Di at the US George Mason University in the US is looking for a writer of the specification. Peter Baumann, rasdaman CEO, was approached, but could not do it earlier due to urgent work on other standards. In 2018, an agreement was finally reached with DIN, the German standardization body, to establish a national project led by Peter Baumann to establish a new abstract coverage specification.

ISO has decided to split the coverage standard into a pair of companion standards, 19123-1 (abstract foundations of coverages) and 19123-2 (concrete, interoperable coverage definition which allows mapping to a variety of data format encodings). The latter, 19123-2, has been adopted by ISO in 2018 from the corresponding OGC Coverage Implementation Schema (CIS) in an ISO project led by Peter Baumann. For the former, 19123-1, the so-called DIN-CONNECT project has submitted a complete specification by the end of the year, fully according to plan. This coverage specification will now become German national standard and simultaneously will be submitted to ISO TC211 as German input to the project.

"It is extremely important to have a coherent set of standards", says Peter Baumann. "We have put utmost emphasis on establishing a specification that is state of the art, open for the future, and yet compatible with the existing coverage standards ecosystem".