HUN GW modelling DEM v01

## **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\nThis dataset contains the following:\n\n\n\nHUN_GW_modelling_DEM.txt - an xyz textfile of 90m resolution elevations for the Hunter GW modelling domain.\n\n\n\nHUN_GW_Model_topography.gdb - an ESRI file geodatabase containing interim rasters used to create the DEM which was exported to the above xyz textfile. The rasters contained are:\n\n\n\n1 HUN_GW_Model_Bathy90 - extract from the source bathymetry layer resampled and reprojected to MGA z56 90m\n\n2 HUN_GW_Model_SRTM90 - extract from the source 3sec SRTM layer resampled and reprojected to MGA z56 90m\n\n3 HUN_Offshore_Bathy90 - (1) above clipped to areas where (2) has cellvalue of 0 (ie SRTM offshore area)\n\n4 HUN_SRTM_Bathy90m_mosaic - (2) with offshore area replaced with (3)\n\n5 HUN_GW_SRTM_Bathy90m_mosaic - (4) clipped to GW model domain\n\n## **Purpose** \n\nInput for groundwater modelling for Hunter subregion.\n\n## **Dataset History** \n\nRectangular extract (encompassing hunter rectagular extent plus some additional offshore area) of source bathymery and SRTM elevation rasters were resampled and reprojected to congruent 90m cell resolution MGA zone 54 rasters.\n\n\n\nThe cell values of the offshore area of the SRTM (ie where cellvalue = 0 or nodata) were replaced with those of the 90m bathymety data to create a seamless mosiac of SRTM elevations on land and bathymetry elevations offshore.\n\n\n\nThis was then clipped to the GW modelling domain and the raster exported as an xyz acii file.\n\n## **Dataset Citation** \n\nBioregional Assessment Programme (2014) HUN GW modelling DEM v01. Bioregional Assessment Derived Dataset. Viewed 22 June 2018, http://data.bioregionalassessments.gov.au/dataset/f0927e8a-cc41-419b-ae68-660d5d5fa47b.\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** [Australian Coal Basins](https://data.gov.au/data/dataset/9d5a8d74-a201-42bd-9d49-3c392244be16)\n\n* **Derived From** [Hunter Groundwater Model extent](https://data.gov.au/data/dataset/6d4a8c97-f7ea-4840-9de9-af6f7b18b8d6)\n\n* **Derived From** [Bathymetry GA 2009 9sec v4](https://data.gov.au/data/dataset/60fb8bf5-b97d-49c9-b7fb-e7d594d2c75b)\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所得。本元数据声明中的**数据谱系（Lineage）**字段已列明所使用的全部源数据集；而制作该衍生数据集所历经的全部处理流程，则见于本元数据声明中的**数据历史（History）**字段。

本数据集包含以下内容：

'HUN_GW_modelling_DEM.txt'：适用于亨特地下水建模域的90米分辨率高程xyz文本文件。

'HUN_GW_Model_topography.gdb'：ESRI文件地理数据库（File Geodatabase），内含用于生成上述xyz文本文件对应数字高程模型（DEM, Digital Elevation Model）的中间栅格数据集，所包含的栅格如下：

1. 'HUN_GW_Model_Bathy90'：源自源水深图层，经重采样与重投影至MGA第56带坐标系的90米分辨率栅格。
2. 'HUN_GW_Model_SRTM90'：源自源3秒SRTM图层，经重采样与重投影至MGA第56带坐标系的90米分辨率栅格。
3. 'HUN_Offshore_Bathy90'：将上述第1项栅格裁剪至第2项栅格像元值为0（即SRTM离岸区域）的范围后得到的栅格。
4. 'HUN_SRTM_Bathy90m_mosaic'：将第2项栅格的离岸区域替换为第3项栅格的对应像元值后得到的无缝镶嵌栅格。
5. 'HUN_GW_SRTM_Bathy90m_mosaic'：将第4项栅格裁剪至地下水（GW）建模域后得到的栅格。

**用途**

用于亨特次区域的地下水建模输入数据。

**数据集历史**

对源水深与SRTM高程栅格进行矩形裁剪（覆盖亨特矩形范围及部分额外离岸区域），随后将其重采样至统一的90米像元分辨率，并重投影至MGA第54带坐标系。

将SRTM栅格的离岸区域（像元值为0或无数据的区域）的像元值替换为90米水深数据的对应值，以此构建陆地区域采用SRTM高程、离岸区域采用水深高程的无缝镶嵌栅格。

随后将该镶嵌栅格裁剪至地下水建模域，并将栅格导出为xyz ASCII文本文件。

**数据集引用**

生物区域评估计划（2014）《亨特地下水建模数字高程模型v01》。生物区域评估计划衍生数据集。查阅于2018年6月22日，http://data.bioregionalassessments.gov.au/dataset/f0927e8a-cc41-419b-ae68-660d5d5fa47b.

**数据集上游来源**

* **衍生自** [澳大利亚地球科学局，3秒SRTM数字高程模型（DEM）v01](https://data.gov.au/data/dataset/12e0731d-96dd-49cc-aa21-ebfd65a3f67a)
* **衍生自** [澳大利亚煤盆地](https://data.gov.au/data/dataset/9d5a8d74-a201-42bd-9d49-3c392244be16)
* **衍生自** [亨特地下水模型范围](https://data.gov.au/data/dataset/6d4a8c97-f7ea-4840-9de9-af6f7b18b8d6)
* **衍生自** [澳大利亚地球科学局2009年9秒水深数据v4](https://data.gov.au/data/dataset/60fb8bf5-b97d-49c9-b7fb-e7d594d2c75b)