Discrete Global Grid Systems – A Framework for the next Era in Big Earth Data

Abstract:

Discrete Global Grid Systems (DGGS) are spatial reference systems that use a hierarchical tessellation of cells to partition and address the entire globe. DGGS are designed to portray real-world phenomena by providing a digital framework on a common discrete geospatial data structure and they are commonly used to create virtual globes. DGGS differ from conventional geographic coordinate reference systems in that they are designed to be an information grid not a navigation grid. Conventional coordinate reference systems address the globe using tuples of “real” numbered coordinates. DGGS, however, address the entire planet by partitioning it into a hierarchical tessellation of integer-based nested cells thereby providing a truly discrete, rather than continuous, reference frame for repeating the location of measured Earth observations, feature interpretations, and extrapolated predictions.

Formal development of DGGS began in the 1980s with the promising value of global analysis coinciding with the increased use of geographic information systems and the availability of global mapping data and positioning systems. However, following the initial excitement about DGGS as a technology the lack of availability of suitable cloud and High Performance Computing (HPC) environments has limited the uptake and application of DGGS – until now! The maturation of accessible cloud and HPC infrastructures has enabled DGGS to emerge from the ‘trough of disillusionment’ and to provide a path to realizing the vision of the Digital Earth, and the future of CyberGIS. The Open Geospatial Consortium (OGC) is developing an international standard for DGGS that will formally define the essential properties of a DGGS and specify protocols that will facilitate interoperability between multiple DGGS and traditional data infrastructures. The OGC DGGS Standards Working Group is finalizing its work based on inputs and review from experts around the world with experinence using multiple DGGSs. By defining cell structure, geo-encoding, quantization strategy and associated mathematical functions, the OGC DGGS Standard will enable interoperable big data processing on discrete global grids.