Global Land Cover Mapping – Need for Discrete Global Grid System

The quality of land cover maps is gradually advancing in terms of increased spatial and temporal resolution, and classification accuracy. However, the aspect of spatial referencing and techniques for representing land cover data has not been advancing. Representing land cover data in the form of a planar raster geospatial data model is still common, despite the various issues especially evident when working with global land cover data. This paper first analyses current approaches in georeferencing global LCLU datasets. Then it examines differences in areal calculations from raster data georeferenced in projected and geographic coordinate reference systems (CRSs). This analysis is performed for the case study of calculating built-up land cover change for the Lebanese 10-km coastal zone. Finally, this paper introduces the topic of discrete global grid systems (DGGSs) as a relatively new approach to handling global geospatial data. DGGSs manage spatial data on the surface of the ellipsoid, rather than in the flattened raster model and thus represent a step forward in managing global geospatial data.