Digital Soil Mapping
McBratney et al. (2000) reviewed pedometric methods for soil survey and suggested three resolutions of interest, namely, >2 km,
20 m-2 km, and <20 m, corresponding to national to global, catchment to landscape, and local extents. Table 37.1 provides an overview with ve resolutions of interest. ¤e third one (D3) that deals with subcatchments, catchments, and regions is the one that attracts the most attention. In the language of digital soil maps (Bishop et al., 2001), which di¦ers from that of conventional cartography, scale is a di¬cult concept and is better replaced by resolution and spacing. D3 surveys, which in conventional terms have a scale of 1:20,000 down to 1:200,000, have a block or cell size from 20 to 200 m, a spacing also of 20-200 m, and a nominal spatial resolution of 40-400 m (see Table 37.1).