GRTSmh_base4frac: the raster data source GRTSmaster_habitats converted to base 4 fractions (Q6717946)

The data source file is a monolayered GeoTIFF in theFLT8Sdatatype. InGRTSmh_base4frac, the decimal (i.e. base 10) integer values from the raster data sourceGRTSmaster_habitats(link) have been converted into base 4 fractions, using a precision of 13 digits behind the decimal mark (as needed to cope with the range of values). For example, the integer16(= 4^2) has been converted into0.0000000000100and4^12has been converted into0.1000000000000. Long base 4 fractions seem to be handled and stored easier than long (base 4) integers. This approach follows the one of Stevens Olsen (2004) to represent the reverse hierarchical order in a GRTS sample as base-4-fraction addresses. See R-code in theGitHub repository n2khab-preprocessing at commit ecadaf5for the creation from theGRTSmaster_habitatsdata source. A reading function to return the data source in a standardized way into the R environmentis provided by the R-package n2khab. Beware that not all GRTS ranking numbers are present in the data source, as the original GRTS raster has been clipped with the Flemish outer borders (i.e., not excluding the Brussels Capital Region).