Soil and Landscape Grid National Soil Attribute Maps - Effective Cation Exchange Capacity (3" resolution) - Release 1

This is Version 1 of the Australian Soil Effective Cation Exchange Capacity product of the Soil and Landscape Grid of Australia. \n\nThe Soil and Landscape Grid of Australia has produced a range of digital soil attribute products. Each product contains six digital soil attribute maps, and their upper and lower confidence limits, representing the soil attribute at six depths: 0-5cm, 5-15cm, 15-30cm, 30-60cm, 60-100cm and 100-200cm. These depths are consistent with the specifications of the GlobalSoilMap.net project (http://www.globalsoilmap.net/). The digital soil attribute maps are in raster format at a resolution of 3 arc sec (~90 x 90 m pixels). \n\nThese maps are generated by combining the best available Digital Soil Mapping (DSM) products available across Australia. \n\nAttribute Definition: Cations extracted using barium chloride (BaCl2) plus exchangeable H + Al; \nUnits: meq/100g; \nPeriod (temporal coverage; approximately): 1950-2013; \nSpatial resolution: 3 arc seconds (approx 90m); \nTotal number of gridded maps for this attribute: 18; \nNumber of pixels with coverage per layer: 2007M (49200 * 40800); \nTotal size before compression: about 8GB; \nTotal size after compression: about 4GB; \nData license : Creative Commons Attribution 4.0 (CC BY); \nTarget data standard: GlobalSoilMap specifications; \nFormat: GeoTIFF.\n\nLineage: The National Soil Attribute Maps are generated by combining the best available digital soil mapping to calculate a variance weighted mean for each pixel. For this soil attribute the Australia-wide three-dimensional Digital Soil Property Maps are the only maps available. Thus the modelling for this soil attribute only used Decision trees with piecewise linear models with kriging of residuals developed from soil site data across Australia. (Viscarra Rossel et al., 2015a).

本数据集为澳大利亚土壤与景观网格（Soil and Landscape Grid of Australia）出品的澳大利亚土壤有效阳离子交换量产品的V1版本。

澳大利亚土壤与景观网格已推出一系列数字土壤属性产品。每套产品包含六组数字土壤属性图及其上下置信限，分别对应6个标准土层深度：0-5cm、5-15cm、15-30cm、30-60cm、60-100cm及100-200cm。上述土层深度与GlobalSoilMap.net项目（http://www.globalsoilmap.net/）的技术规范完全一致。该系列数字土壤属性图采用栅格格式，分辨率为3角秒（约90×90米像素）。

此类地图通过整合澳大利亚境内可获取的最优数字土壤制图（Digital Soil Mapping，DSM）产品生成。

属性定义：采用氯化钡（BaCl₂）与交换性氢+铝联合萃取的阳离子总量；单位：meq/100g；时间覆盖范围：约1950-2013年；空间分辨率：3角秒（约90米）；该属性的网格化地图总数量：18幅；单图层有效覆盖像素数：2007M（49200×40800）；压缩前总数据量：约8GB；压缩后总数据量：约4GB；数据许可协议：知识共享署名4.0（Creative Commons Attribution 4.0，CC BY）；目标数据标准：GlobalSoilMap规范；数据格式：GeoTIFF。

数据谱系：全国土壤属性图通过整合现有最优数字土壤制图方法，为每个像素计算方差加权均值生成。针对该土壤属性，澳大利亚全境的三维数字土壤属性图为当前仅有的可用数据集。因此，本土壤属性的建模仅采用了搭载分段线性模型的决策树，并结合基于澳大利亚全域土壤样点数据生成的残差克里金插值方法（Viscarra Rossel等，2015a）。