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S-map will provide a consistent and comprehensive national soil data layers to support applications at local, and regional to national scales. In time, S-map will have national coverage and contain predominantly new digital data at a scale that resolves soil variation on hill slopes (nominally 1:50 000 scale). S-map's primary map layer is soil mapunits, i.e. delineated areas that contain the same soils and are labelled with a soil mapunit identifier (SMU). S-map soils are classified into soil families. Each soil family is defined as a unique combination of attributes (NZSC classification, parent material, rock type, dominant texture and permeability class). Soil classes are further characterised as siblings according to their depth to rock class, stoniness, land type, drainage, texture (more detailed), functional horizons and miscellaneous variant information. The uncertainty of each of these family and sibling attribute classes is also recorded. S-map includes data on the key soil properties of depth (diggability), depth to slowly permeable layer, rooting depth, rooting barrier, horizon thickness, stoniness, clay and sand content. They are developed from soil sample information and expert knowledge. Further soil information is derived from a model (or pedo-transfer function). Some models are simple lookup tables that depend only on the soil class. Others combine various soil, land use, vegetation, climate or topographic attributes in a mathematical formula. Derived information includes available water (mm), macroporosity, water retention, bulk density, and phosphorus retention.Please refer to document Smap Data Dictionary Soil Polygons.pdf (https://lris.scinfo.org.nz/document/21643-smap-data-dictionary-soil-polygons/) for further details of the polygon layer attributes.Source: S-map builds on previous soil mapping by filling gaps with new mapping, and upgrading the information content and associated database to meet a new national standard. |