soilmap_simple: a simplified and standardized derivative of the digital soil map of the Flemish Region

The data source soilmap_simple is a simplified and standardized derived form of the 'digital soil map of the Flemish Region' (the shapefile of which we named soilmap, for analytical workflows in R) published by 'Databank Ondergrond Vlaanderen’ (DOV). It is a GeoPackage that contains a spatial polygon layer ‘soilmap_simple’ in the Belgian Lambert 72 coordinate reference system (EPSG-code 31370), plus a non-spatial table ‘explanations’ with the meaning of category codes that occur in the spatial layer. Further documentation about the digital soil map of the Flemish Region is available in Van Ranst & Sys (2000) and Dudal et al. (2005). This version of soilmap_simple was derived from version 'soilmap_2017-06-20' (Zenodo DOI) as follows: all attribute variables received English names (purpose of standardization), starting with prefix bsm_ (referring to the 'Belgian soil map'); attribute variables were reordered; the values of the morphogenetic substrate, texture and drainage variables (bsm_mo_substr, bsm_mo_tex and bsm_mo_drain + their _explan counterparts) were filled for most features in the 'coastal plain' area. To derive morphogenetic texture and drainage levels from the geomorphological soil types, a conversion table by Bruno De Vos & Carole Ampe was applied (for earlier work on this, see Ampe 2013). Substrate classes were copied over from bsm_ge_substr into bsm_mo_substr (bsm_ge_substr already followed the categories of bsm_mo_substr). These steps coincide with the approach that had been taken to construct the Unitype variable in the soilmap data source; only a minimal number of variables were selected: those that are most useful for analytical work. See R-code in the GitHub repository 'n2khab-preprocessing' at commit b3c6696 for the creation from the soilmap data source. A reading function to return soilmap_simple (this data source) or soilmap in a standardized way into the R environment is provided by the R-package n2khab. The attributes of the spatial polygon layer soilmap_simple can have mo_ in their name to refer to the Belgian Morphogenetic System: bsm_poly_id: unique polygon ID (numeric) bsm_region: name of the region bsm_converted: boolean. Were morphogenetic texture and drainage variables (bsm_mo_tex and bsm_mo_drain) derived from a conversion table (see above)? Value TRUE is largely confined to the 'coastal plain' areas. bsm_mo_soilunitype: code of the soil type (applying morphogenetic codes within the coastal plain areas when possible, just as