Data source for polygonal data used by the ASRIS project in generation of modelled surfaces

Data provided are the scale of polygonal datasources used to generate the polygon derived surfaces for the intensive agricultural areas of Australia. Data modelled from area based observations made by State soil agencies.The final ASRIS polygon attributed surfaces are a mosaic of all of the data obtained from various state and federal agencies. The surfaces have been constructed with the best available soil survey information available at the time. The surfaces also rely on a number of assumptions. One being that an area weighted mean is a good estimate of the soil attributes for that polygon or mapunit. Another assumption made is that the lookup tables provided by McKenzie et al. (2000), state and territories accurately depict the soil attribute values for each soil type.The accuracy of the maps is most dependent on the scale of the original polygon data sets and the level of soil survey that has taken place in each state. The scale of the various soil maps used in deriving this map is available by accessing darasource grid, the scale is used as an assessment of the likely accuracy of the modelling.The Atlas of Australian Soils is considered to be the least accurate dataset and has therefore only been used where there is no state based data.Of the state datasets Western Australian sub-systems, South Australian land systems and NSW soil landscapes and reconnaissance mapping would be the most reliable based on scale. NSW soil landscapes and reconnaissance mapping however, may be less accurate than South Australia and Western Australia as only one dominant soil type per polygon was used in the estimation of attributes, compared to several soil types per polygon or mapunit in South Australia and Western Australia. NSW soil landscapes and reconnaissance mapping as the name suggests is reconnaissance level only with no laboratory data. The digital map data is provided in geographical coordinates based on the World Geodetic System 1984 (WGS84) datum.

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