GRTSmh_diffres: the raster data source GRTSmaster_habitats converted to 9 hierarchical cell address levels at the corresponding lower resolution

The GRTSmh_diffres data source file is a file collection, composed of nine monolayered GeoTIFF files of the INT4S datatype plus a GeoPackage with six polygon layers: The polygon layers in the GeoPackage are the dissolved, polygonized versions of levels 4 to 9 of the GRTSmh_brick data source (link). This means that they provide the decimal (i.e. base 10) integer values of these higher hierarchical levels of the GRTS cell addresses of the raw data source GRTSmaster_habitats (link). Hence, the polygons are typically squares that correspond to the GRTS cell at the specified hierarchical level. The polygon layer is however restricted to the non-NA cells of the original GRTSmaster_habitats raster. Consequently, a part of the polygons is clipped along the Flemish border. Levels 1 to 3 are not provided for the whole of Flanders, because this would inflate the GPKG file. You can look at the source code to do such things. The GeoTIFF files provide the respective levels 1 to 9 of the GRTSmh_brick data source in a raster format, at the resolution that corresponds to the GRTS cell at the specified hierarchical level. The presence of NA cells around Flanders at level 0 implies that, with decreasing resolution, the raster's extent increases and larger areas outside Flanders are covered by non-NA cells along the border. The higher-level ranking numbers (compared to the original level 0) allow spatially balanced samples at lower spatial resolution than that of 32 m, and can also be used for aggregation purposes. See R-code in the GitHub repository 'n2khab-preprocessing' at commit ecadaf5 for the creation from the GRTSmh_brick data source. A reading function to return the data source in a standardized way into the R environment is provided by the R-package n2khab. Beware that not all GRTS ranking numbers at the specified level are provided, as the original GRTS raster has been clipped with the Flemish outer borders (i.e., not excluding the Brussels Capital Region).