Soilscapes are defined as "a landscape unit including a limited number of soil classes that are geographically distributed according to an identifiable pattern". These first approximation soilscapes are derived from legacy data and expert knowledge.
Soilscapes for the North Island were based in a map of 'erosion terrains' derived from the NZ Land Resource Inventory (NWASCO, 1979). Although originally intended for erosion studies, the erosion terrains efficiently stratified soil patterns and rock types relevant to soilscapes mapping. Soilscapes for the South Island were based on the earlier map of 'soil sets' for the South Island similar in concept to 'land systems' (Soil Survey Staff 1968). Soilscapes were arranged in a hierarchy of 6 levels; level 1, land province - major climate, geologic terrains and landscape units, level 2, land region - major physiographic units, level 3, lithology - major rock and cover material types, level 4, climate, level 5, altitude, and level 6, slope and landforms. For the national scale Digital Soil Mapping (DSM) we used soilscapes at level 5 for the South Island and soilscapes at level 3 for the North Island. Climate (level 4) and altitude (altitude level 5) were not used for the North Island because these factors were less variable and were of less significance than in the South Island. Level 6 landform and slope attributes was not used because they stratified finer scale variations considered more relevant for local rather than national planning. This provided for analysis 193 soilscapes nationally (52 for the North Island and 141 for the South Island).