Great Artesian Basin - Cadna-owie Hooray Aquifer - Sodium Concentration

Data used to produce the predicted Sodium map for the Cadna-owie - Hooray Aquifer in the Hydrogeological Atlas of the Great Artesian Basin (Ransle et. al., 2015).There are four layers in the Cadna-owie - Hooray Aquifer Sodium map dataA. Location of hydrochemistry samples (Point data, Shapefile)B. Predicted Concentration (Filled contours , Shapefile)C. Predicted Concentration Contours (Contours, Shapefile)D. Prediction Standard Error (Filled contours , Shapefile)The predicted values provide a regional based estimate and may be associated with considerable error. It is recommended that the predicted values are read together with the predicted error map, which provides an estimate of the absolute standard error associated with the predicted values at any point within the map.The predicted standard error map provides an absolute standard error associated with the predicted values at any point within the map. Please note this is not a relative error map and the concentration of a parameter needs to be considered when interpreting the map. Predicted standard error values are low where the concentration is low and there is a high density of samples. Predicted standard errors values can be high where the concentration is high and there is moderate variability between nearby samples or where there is a paucity of data.Concentrations are Sodium as Na in mg/L.Coordinate system is Lambert conformal conic GDA 1994, with central meridian 134 degrees longitude, standard parallels at -18 and -36 degrees latitude.The Cadna-owie - Hooray Aquifer Sodium map is one of 14 hydrochemistry maps for the Cadna-owie - Hooray Aquifer and 24 hydrochemistry maps in the Hydrogeological Atlas of the Great Artesian Basin (Ransley et. al., 2014). This dataset and associated metadata can be obtained from www.ga.gov.au, using catalogue number 81695. References:Hitchon, B. and Brulotte, M. (1994): Culling criteria for 'standard' formation water analyses; Applied Geochemistry, v. 9, p. 637-645Ransley, T., Radke, B., Feitz, A., Kellett, J., Owens, R., Bell, J. and Stewart, G., 2015. Hydrogeological Atlas of the Great Artesian Basin. Geoscience Australia. Canberra. [available from www.ga.gov.au using catalogue number 79790]

本数据集用于生成《大自流盆地水文地质图集（Hydrogeological Atlas of the Great Artesian Basin）》中Cadna-owie-Hooray含水层的钠元素预测分布图（Ransle等，2015）。Cadna-owie-Hooray含水层钠元素分布图数据包含4个图层：
A. 水文化学采样点位数据（点数据，Shapefile）
B. 预测浓度（等值填充面，Shapefile）
C. 预测浓度等值线（等值线，Shapefile）
D. 预测标准误差（等值填充面，Shapefile）

该预测值仅提供区域尺度的估算结果，可能伴随显著误差。建议将预测值与预测误差图结合解读，该误差图可估算地图内任意点位对应预测值的绝对标准误差。需注意，本预测标准误差图仅提供地图内任意点位对应预测值的绝对标准误差，并非相对误差图，解读时需结合参数的浓度水平。当浓度较低且采样点密度较高时，预测标准误差值较低；当浓度较高、相邻采样点间变异程度中等或数据匮乏时，预测标准误差值较高。

浓度单位为以钠（Na）计的毫克每升（mg/L）。

坐标系采用兰伯特共形圆锥投影GDA 1994（Lambert conformal conic GDA 1994），中央经线为东经134度，标准纬线为南纬18度与南纬36度。

Cadna-owie-Hooray含水层钠元素分布图是该含水层的14张水文化学图之一，同时也是《大自流盆地水文地质图集》（Ransley等，2014）收录的24张水文化学图之一。本数据集及相关元数据可通过澳大利亚地质科学局官网www.ga.gov.au获取，目录编号为81695。

参考文献：
1. Hitchon, B. 与 Brulotte, M. (1994)：《"标准"地层水分析的筛选标准》，《应用地球化学》，第9卷，第637-645页
2. Ransley, T., Radke, B., Feitz, A., Kellett, J., Owens, R., Bell, J. 与 Stewart, G., 2015. 《大自流盆地水文地质图集》，澳大利亚地质科学局（Geoscience Australia），堪培拉。[可通过目录编号79790在www.ga.gov.au获取]