Dynamic land cover - Gippsland Basin bioregion clip

## **Abstract** \n\nThis dataset was derived by the Bioregional Assessment Programme from The Dynamic Landcover Dataset of Australia dataset (GUID: b85713ee-5fa3-44a5-b145-25b01efa3e31). 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.\n\n\n\nThis dataset includes:\n\n1. A clip of the dataset 'The Dynamic Landcover Dataset of Australia' to the Gippsland Basin Bioregion boundary\n\n2. A table showing land cover statistics for the Gippsland Basin Bioregion\n\n## **Dataset History** \n\nThe Dynamic Landcover Dataset of Australia (https://data.bioregionalassessments.gov.au/datastore/dataset/b85713ee-5fa3-44a5-b145-25b01efa3e31) was clipped by the Gippsland Basin bioregion project boundary (https://data.bioregionalassessments.gov.au/datastore/dataset/27413de5-d13a-4231-ac79-fc77f4cbb5f7) in ArcMap 10.2 using the 'Extract by Mask (Spatial Analyst)' tool. \n\n\n\nLand cover statistics were derived from the clipped dataset by:\n\n1. Using the 'Summary Statistics (Analysis)' tool in ArcCatalog 10.2 with the following inputs: Statistics Field = 'COUNT', Statistic Type = SUM, Case Field = CLASSLABEL \n\n2. A new field (type: double) named 'AREA_SQ_KM' was added and the area calculated using the following equation \\[SUM_COUNT\\]\\*0.0625. This is because the SUM_COUNT field indicates the number of 250mx250m grid cells.\n\n3. The percentage of total Gippsland Basin bioregion area was calculated in a new field (type: float) named AREA_PERC using (\\[AREA_SQ_KM\\]/the total covered area)\\*100.\n\n\n\n\\*Note that the area calculations in the table are based on a 250m cell resolution. This is incorrect as the actual cell size is approximately 267 x 267m. The calculated percentages are correct.\n\n## **Dataset Citation** \n\nBioregional Assessment Programme (2014) Dynamic land cover - Gippsland Basin bioregion clip. Bioregional Assessment Derived Dataset. Viewed 29 September 2017, http://data.bioregionalassessments.gov.au/dataset/01631b54-16a3-4a84-8dac-3e8d142e12b9.\n\n## **Dataset Ancestors** \n\n* **Derived From** [Victoria - Seamless Geology 2014](https://data.gov.au/data/dataset/2872d02e-66cb-42b6-9e5a-63abc8ad871b)\n\n* **Derived From** [Gippsland Project boundary](https://data.gov.au/data/dataset/27413de5-d13a-4231-ac79-fc77f4cbb5f7)\n\n* **Derived From** [GEODATA TOPO 250K Series 3](https://data.gov.au/data/dataset/a0650f18-518a-4b99-a553-44f82f28bb5f)\n\n* **Derived From** [The Dynamic Landcover Dataset of Australia](https://data.gov.au/data/dataset/b85713ee-5fa3-44a5-b145-25b01efa3e31)\n\n

## 摘要
本数据集由生物区域评估项目源自《澳大利亚动态土地覆盖数据集》（全局唯一标识符（Globally Unique Identifier，GUID）：b85713ee-5fa3-44a5-b145-25b01efa3e31）。您可在本元数据说明的"谱系字段"中找到父数据集的链接。本元数据说明的"历史字段"则记述了本数据集的衍生过程。

本数据集包含：
1. 裁剪至吉普斯兰盆地生物区域边界的《澳大利亚动态土地覆盖数据集》片段
2. 展示吉普斯兰盆地生物区域土地覆盖统计数据的表格

## 数据集历史
《澳大利亚动态土地覆盖数据集》（https://data.bioregionalassessments.gov.au/datastore/dataset/b85713ee-5fa3-44a5-b145-25b01efa3e31）已通过ArcMap 10.2中的"按掩膜提取（空间分析）"工具，以吉普斯兰盆地生物区域项目边界（https://data.bioregionalassessments.gov.au/datastore/dataset/27413de5-d13a-4231-ac79-fc77f4cbb5f7）为掩膜完成裁剪。

土地覆盖统计数据的衍生步骤如下：
1. 使用ArcCatalog 10.2中的"汇总统计数据（分析）"工具，输入参数为：统计字段 = 'COUNT'，统计类型 = 求和（SUM），分组字段 = CLASSLABEL
2. 新增一个双精度类型字段`AREA_SQ_KM`，并通过公式`[SUM_COUNT] * 0.0625`计算面积：因`SUM_COUNT`字段代表250米×250米网格单元的数量。
3. 在新增的浮点型字段`AREA_PERC`中计算吉普斯兰盆地生物区域总占比百分比，公式为`([AREA_SQ_KM] / 总覆盖面积) * 100`。

*注：表格中的面积计算基于250米的单元格分辨率，这存在错误——实际单元格尺寸约为267米×267米，但计算得出的百分比数值准确无误。

## 数据集引用
生物区域评估项目（2014）《动态土地覆盖——吉普斯兰盆地生物区域裁剪数据集》，生物区域评估衍生数据集。查阅于2017年9月29日，http://data.bioregionalassessments.gov.au/dataset/01631b54-16a3-4a84-8dac-3e8d142e12b9。

## 数据集上游来源
* **衍生自** [维多利亚州2014年无缝地质数据](https://data.gov.au/data/dataset/2872d02e-66cb-42b6-9e5a-63abc8ad871b)
* **衍生自** [吉普斯兰项目边界](https://data.gov.au/data/dataset/27413de5-d13a-4231-ac79-fc77f4cbb5f7)
* **衍生自** [GEODATA 250K第3系列地形数据](https://data.gov.au/data/dataset/a0650f18-518a-4b99-a553-44f82f28bb5f)
* **衍生自** [澳大利亚动态土地覆盖数据集](https://data.gov.au/data/dataset/b85713ee-5fa3-44a5-b145-25b01efa3e31)