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

本次提供的数据为用于生成澳大利亚集约化农业区域多边形衍生曲面的各类多边形数据源的空间尺度信息。本数据集基于各州土壤机构开展的区域实地观测数据建模生成。澳大利亚土壤资源信息系统（Australian Soil Resource Information System, ASRIS）最终生成的带属性多边形曲面，是整合各州及联邦机构获取的全部数据拼接而成的镶嵌数据集。该曲面基于研究时段内可获取的最优土壤调查信息构建，同时依托多项假设前提：其一，采用面积加权平均法可较好地估算对应多边形或制图单元的土壤属性；其二，McKenzie等人（2000）以及澳大利亚各州和领地发布的查询表，可准确表征各类土壤类型的土壤属性值。
该地图的精度主要取决于原始多边形数据集的空间尺度，以及各州开展的土壤调查工作等级。本次制图所使用的各类土壤地图的空间尺度可通过数据源网格（datasource grid）查询，该尺度可用于评估建模结果的潜在精度。《澳大利亚土壤图集》被认为是精度最低的数据集，因此仅在无各州官方数据可用的场景下才会被采用。
在各州数据集当中，从空间尺度来看，西澳大利亚州子系统、南澳大利亚州土地系统以及新南威尔士州土壤景观与普查制图的可靠性最高。但新南威尔士州土壤景观与普查制图的精度可能低于南澳与西澳数据集：该类数据在属性估算中仅采用每个多边形内的一种优势土壤类型，而南澳与西澳的数据集则会考虑每个多边形或制图单元内的多种土壤类型。顾名思义，新南威尔士州土壤景观与普查制图仅属于普查级别的数据，未附带实验室分析数据。
本次提供的数字地图数据采用基于1984世界大地测量系统（World Geodetic System 1984, WGS84）的地理坐标系。如需获取更多详细信息，请参阅[补充元数据](http://data.daff.gov.au/anrdl/metadata_files/pa_dams_r9cl__04011a00.xml)