GAL Assessment Units 1000m 20160522 v01

## **Abstract** \r\n\r\nThe dataset was derived by the Bioregional Assessment Programme. This dataset was derived from multiple datasets. You can find a link to the parent datasets in the Lineage Field in this metadata statement. The History Field in this metadata statement describes how this dataset was derived.\r\n\r\n\r\n\r\nTo ensure efficiency for processing speed and rendering this is a clip of the Vector Reference grid for the GAL region.\r\n\r\nIt was created with a 50km buffer of the extent of the Hunter PAE and then selecting all grid cells that intersect with the extent.\r\n\r\nThe unique ID field for each grid cell is AUID and starts from 1 in the reference grid. The grid also has a column id and row for easy reference\r\n\r\nThe grid is in Australia Albers (GDA94) (EPSG 3577)\r\n\r\n## **Purpose** \r\n\r\nThis is an attempt to standardise (where possible) outputs of models from BA assessments and is the template to be used for GAL (clipped from whole of BA reference Grid) for the groundwater and potentially surface water model outputs.\r\n\r\n## **Dataset History** \r\n\r\nThe minimum bounding geometry tool in ArcGIS 10.1 was used to return the extent of the Bioregion boundary. This was then buffered with a 50km radius.\r\n\r\nThe select location tool in ArcGIS 10.1 was then used to select all gridcells within the buffered extent.\r\n\r\nAn export of the grid cells was then created to produce a rectangle reference grid of the GAL region.\r\n\r\nThe file contains 2 shape files \r\n\r\n1) The grid cells clipped to the boundary\r\n\r\n2) The boundary extents as a reference of the Region\r\n\r\n## **Dataset Citation** \r\n\r\nBioregional Assessment Programme (XXXX) GAL Assessment Units 1000m 20160522 v01. Bioregional Assessment Derived Dataset. Viewed 12 December 2018, http://data.bioregionalassessments.gov.au/dataset/96dffeea-5208-4cfc-8c5d-408af9ac508e.\r\n\r\n## **Dataset Ancestors** \r\n\r\n* **Derived From** [BA ALL Assessment Units 1000m Reference 20160516_v01](https://data.gov.au/data/dataset/d044b1d9-40b0-4fc3-ae43-099cc7b96497)\r\n\r\n* **Derived From** [BA ALL Assessment Units 1000m 'super set' 20160516_v01](https://data.gov.au/data/dataset/6c1aa99e-c973-4472-b434-756e60667bfa)\r\n\r\n

## **摘要**
本数据集由生物区域评估计划（Bioregional Assessment Programme）编制，源自多个数据集。您可在本元数据声明的**谱系字段（Lineage Field）**中找到源数据集的链接，元数据声明中的**历史字段（History Field）**则说明了本数据集的编制流程。

为提升处理速度与渲染效率，本数据集为GAL区域矢量参考网格的裁剪子集。

其制作流程为：先对Hunter PAE的范围构建50km缓冲区，再选取所有与该缓冲范围相交的网格单元。

每个网格单元的唯一标识符字段为AUID，在参考网格中从1开始编号。该网格同时包含列编号（column id）与行编号（row）字段，便于快速检索。

该网格采用澳大利亚阿尔伯斯（GDA94）坐标系（EPSG 3577）。

## **目的**
本数据集旨在尽可能统一生物区域评估（Bioregional Assessment, BA）模型的输出结果，同时作为GAL区域（从完整BA参考网格裁剪得到）地下水及潜在地表水模型输出的标准模板。

## **数据集历史**
使用ArcGIS 10.1中的最小外包几何工具获取生物区域边界范围，随后以该范围为基础构建50km半径的缓冲区。

再使用ArcGIS 10.1中的位置选择工具，选取缓冲范围内的所有网格单元。

随后导出所选网格单元，生成GAL区域的矩形参考网格。

本数据集包含2个shapefile文件：
1) 裁剪至边界的网格单元图层
2) 作为区域参考的边界范围图层

## **数据集引用**
生物区域评估计划（Bioregional Assessment Programme）. GAL评估单元1000m 20160522 v01. 生物区域评估衍生数据集. 2018年12月12日查阅, http://data.bioregionalassessments.gov.au/dataset/96dffeea-5208-4cfc-8c5d-408af9ac508e.

## **数据集前身**
* **数据源自** [BA全域评估单元1000m参考数据集20160516_v01](https://data.gov.au/data/dataset/d044b1d9-40b0-4fc3-ae43-099cc7b96497)
* **数据源自** [BA全域评估单元1000m「超集」数据集20160516_v01](https://data.gov.au/data/dataset/6c1aa99e-c973-4472-b434-756e60667bfa)