Classified depth to water table for the Great Artesian Basin

## **Abstract** \n\nThe dataset was derived by the Bioregional Assessment Programme from multiple source datasets. The source datasets are identified in the Lineage field in this metadata statement. The processes undertaken to produce this derived dataset are described in the History field in this metadata statement.\n\n\n\nCategorised depth to groundwater in the Great Artesian Basin. \n\nCategories are: (Depth indicated is meters below surface, surface elevation taken from 3 Second SRTM DEM-s) \n\n1 = 0 - 5m \n\n2 = 5 - 10m\n\n3 = 10 - 15m\n\n4 = 15 - 20m\n\n5 = 20 - 25m\n\n6 = 25 - 30m\n\n7 = 30 - 35m\n\n8 = 35 - 40m\n\n9 = +40m\n\n## **Dataset History** \n\nGrid derived from subtracting the GAB waterlevel elevation surface from the GA 3second SRTM DEM-s\n\n\n\n1. Depth to water table grid created using Raster Calculator. \\[GA 3sec SRTM DEM-s\\] - \\[GAB water table grid\\], Grid: float, produced.\n\n2. QA/QC on float grid to remove values < 0 (water table above surface)\n\n3. Artefacts still exist with high values up to 750m. This issue is resolved by classifying the grid (using the Spatial Analyst, Reclassify tool) into 5m intervals up to 40m than a final category of >40m. This final output is the available grid within this dataset.\n\n## **Dataset Citation** \n\nBioregional Assessment Programme (XXXX) Classified depth to water table for the Great Artesian Basin. Bioregional Assessment Derived Dataset. Viewed 30 September 2016, http://data.bioregionalassessments.gov.au/dataset/6eabd9e1-0018-4314-bba4-87d5d1ebc8c3.\n\n## **Dataset Ancestors** \n\n* **Derived From** [Geoscience Australia, 3 second SRTM Digital Elevation Model (DEM) v01](https://data.gov.au/data/dataset/12e0731d-96dd-49cc-aa21-ebfd65a3f67a)\n\n* **Derived From** [Water table elevation of the Great Artesian Basin (GABWRA)](https://data.gov.au/data/dataset/08f01dba-ec93-4c00-8e29-2b25a1948a33)\n\n

**摘要** 本数据集由生物区域评估计划（Bioregional Assessment Programme）基于多源数据集衍生而成。源数据集的相关信息详见本元数据声明中的谱系（Lineage）字段，本衍生数据集的生成流程则详见本元数据声明中的历史（History）字段。

大自流盆地（Great Artesian Basin）地下水埋深分类数据集。
分类标准如下（标注埋深为地表以下米数，地表高程取自3秒分辨率SRTM DEM-s数据）：
1 = 0~5米
2 = 5~10米
3 = 10~15米
4 = 15~20米
5 = 20~25米
6 = 25~30米
7 = 30~35米
8 = 35~40米
9 = ≥40米

**数据集生成历史** 本栅格数据由澳大利亚地球科学局3秒分辨率SRTM DEM-s地表高程数据减去大自流盆地地下水位高程栅格得到。
1. 利用栅格计算器（Raster Calculator）生成地下水位埋深栅格：[GA 3秒SRTM DEM-s] - [大自流盆地地下水位栅格]，输出为浮点型栅格。
2. 对浮点型栅格开展质量控制与质量保证（QA/QC），剔除小于0的值（即地下水位高于地表的异常值）。
3. 仍存在最高达750米的异常值，通过空间分析工具（Spatial Analyst）的重分类（Reclassify）工具将栅格按5米间隔划分为0~40米共8个类别，另设≥40米的最终类别以解决异常值问题。本数据集的可用栅格即为该最终重分类结果。

**数据集引用说明** 生物区域评估计划（XXXX）. 大自流盆地地下水埋深分类数据集. 生物区域评估衍生数据集. 2016年9月30日查阅, http://data.bioregionalassessments.gov.au/dataset/6eabd9e1-0018-4314-bba4-87d5d1ebc8c3.

**数据集溯源**
* **数据来源** [澳大利亚地球科学局，3秒分辨率SRTM数字高程模型（DEM）v01](https://data.gov.au/data/dataset/12e0731d-96dd-49cc-aa21-ebfd65a3f67a)
* **数据来源** [大自流盆地地下水位高程数据集（GABWRA）](https://data.gov.au/data/dataset/08f01dba-ec93-4c00-8e29-2b25a1948a33)