The raster_runif data source covers the Flanders and Brussels region and has a resolution of 32 meters. The raster cells with non-missing values match the value-cells of the GRTSmaster_habitats data source with a small buffer added. Every raster cell has a random value between 0 and 1 according to the uniform distribution. An example usage of this raster is its combination with the GRTSmaster_habitats and habitatmap_stdized data sources in order to draw an equal probability sample of habitat types in Flanders. Habitatmap_stdized contains polygons that are partially or fully covered by habitat types. The proportion of a certain type within a polygon is provided by the phab value. We can draw an equal probability sample size n for a certain habitat type as follows: select all raster cells of GRTSmaster_habitats that overlap with the sampling frame of the target habitat type keep the raster cells for which the raster_runif value is lower than the phab value of the habitat type within the polygon finally select the n raster cells with the lowest GRTS ranking number. The R-code for creating the raster_runif data source can be found in the GitHub repository 'n2khab-preprocessing' at commit ede43a4. A reading function to return the data source in a standardized way into the R environment is provided by the R-package n2khab.