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

\n\nData provided are the scale of polygonal datasources used to generate the\npolygon derived surfaces for the intensive agricultural areas of Australia.\nData modelled from area based observations made by State soil agencies.The\nfinal ASRIS polygon attributed surfaces are a mosaic of all of the data\nobtained from various state and federal agencies. The surfaces have been\nconstructed with the best available soil survey information available at the\ntime. The surfaces also rely on a number of assumptions. One being that an\narea weighted mean is a good estimate of the soil attributes for that polygon\nor mapunit. Another assumption made is that the lookup tables provided by\nMcKenzie et al. (2000), state and territories accurately depict the soil\nattribute values for each soil type.The accuracy of the maps is most dependent\non the scale of the original polygon data sets and the level of soil survey\nthat has taken place in each state. The scale of the various soil maps used in\nderiving this map is available by accessing darasource grid, the scale is used\nas an assessment of the likely accuracy of the modelling.The Atlas of\nAustralian Soils is considered to be the least accurate dataset and has\ntherefore only been used where there is no state based data.Of the state\ndatasets Western Australian sub-systems, South Australian land systems and NSW\nsoil landscapes and reconnaissance mapping would be the most reliable based on\nscale. NSW soil landscapes and reconnaissance mapping however, may be less\naccurate than South Australia and Western Australia as only one dominant soil\ntype per polygon was used in the estimation of attributes, compared to several\nsoil types per polygon or mapunit in South Australia and Western Australia.\nNSW soil landscapes and reconnaissance mapping as the name suggests is\nreconnaissance level only with no laboratory data. The digital map data is\nprovided in geographical coordinates based on the World Geodetic System 1984\n(WGS84) datum.\n\nSee [further metadat](http://data.daff.gov.au/anrdl/metadata_files/pa_dams_r9cl_\n_04011a00.xml) for more detail.\n\n