World Soils 250m Organic Carbon Density

Soil is the foundation of life on earth. More living things by weight live in the soil than upon it. It determines what crops we can grow, what structures we can build, what forests can take root. This layer contains the chemical soil variable organic carbon density (ocd) which measures carbon mass in proportion to volume of soil (mass divided by volume.) From Agriculture Victoria: Soil carbon provides a source of nutrients through mineralisation, helps to aggregate soil particles (structure) to provide resilience to physical degradation, increases microbial activity, increases water storage and availability to plants, and protects soil from erosion. This layer is a general, medium scale global predictive soil layer suitable for global mapping and decision support. In many places samples of soils do not exist so this map represents a prediction of what is most likely in that location. The predictions are made in six depth ranges by soilgrids.org, funded by ISRIC based in Wageningen, Netherlands. Each 250m pixel contains a value predicted for that area by soilgrids.org from best available data worldwide. Data for organic carbon density are provided at six depth ranges from the surface to 2 meters below the surface. Each variable and depth range may be accessed in the layer's multidimensional properties. Dataset Summary Phenomenon Mapped: Organic carbon density in kg/m³ Cell Size: 250 meters Pixel Type: 32 bit float, converted from online data that is 16 Bit Unsigned Integer Coordinate System: Web Mercator Auxiliary Sphere, projected via nearest neighbor from goode's homolosine land (250m) Extent: World land area except Antarctica Visible Scale: All scales are visible Number of Columns and Rows: 160300, 100498 Source: Soilgrids.org Publication Date: May 2020 Analysis: Analysis-Optimized Data from the soilgrids.org mean predictions for ocd were used to create this layer. You may access organic carbon density values in one of six depth ranges. To select one choose the depth variable in the multidimensional selector in your map client. Mean depth (cm) Actual depth range of data -2.5 0-5cm depth range -10 5-15cm depth range -22.5 15-30cm depth range -45 30-60cm depth range -80 60-100cm depth range -150 100-200cm depth range What can you do with this Layer? This layer is suitable for both visualization and analysis across the ArcGIS system. This layer can be combined with your data and other layers from the ArcGIS Living Atlas of the World in ArcGIS Online and ArcGIS Pro to create powerful web maps that can be used alone or in a story map or other application. Read more in our blogs: Dsicoveries and Revelations: Exploring the World Soils 250m Layers Getting Started with Multidimensional Soil Layers in the ArcGIS Living Atlas of the World Because this layer is part of the ArcGIS Living Atlas of the World it is easy to add to your map: In ArcGIS Online, you can add this layer to a map by selecting Add then Browse Living Atlas Layers. A window will open. Type "world soils soilgrids" in the search box and browse to the layer. Select the layer then click Add to Map. In ArcGIS Pro, open a map and select Add Data from the Map Tab. Select Data at the top of the drop down menu. The Add Data dialog box will open on the left side of the box, expand Portal if necessary, then select Living Atlas. Type "world soils soilgrids" in the search box, browse to the layer then click OK. In ArcGIS Pro you can use the built-in raster functions or create your own to create custom extracts of the data. Imagery layers provide fast, powerful inputs to geoprocessing tools, models, or Python scripts in Pro. Online you can filter the layer to show subsets of the data using the filter button and the layer's built-in raster functions. This layer is part of the Living Atlas of the World that provides an easy way to explore the landscape layers and many other beautiful and authoritative maps on hundreds of topics. Analysis In order to leverage the optimization for analysis, the capability must be enabled by your ArcGIS organization administrator. More information on enabling this feature can be found in the ‘Regional data hosting’ section of this help doc. Optimized for analysis means this layer does not have size constraints for analysis and it is recommended for multisource analysis with other layers optimized for analysis. See the ArcGIS Living Atlas: Analysis-Optimized Imagery Layers Group for a complete list of imagery layers optimized for analysis. More information about soilgrids layers Answers to many questions may be found at soilgrids.org (ISRIC) frequently asked questions (faq) page about the data. To make this layer, Esri reprojected the expected value of ISRIC soil grids from soilgrids' source projection (goode's land WKID 54052) to web mercator projection, nearest neighbor, to facilitate online mapping. The resolution in web mercator projection is the same as the original projection, 250m. But keep in mind that the original dataset has been reprojected to make this web mercator version. This multidimensional soil collection serves the mean or expected value for each soil variable as calculated by soilgrids.org. For all other distributions of the soil variable, be sure to download the data directly from soilgrids.org. The data are available in VRT format and may be converted to other image formats within ArcGIS Pro. Accessing this layer's companion uncertainty layer Because data quality varies worldwide, the uncertainty of the predicted value varies worldwide. A companion uncertainty layer exists for this layer which you can use to qualify the values you see in this map for analysis. Choose a variable and depth in the multidimensional settings of your map client to access the companion uncertainty layer.土壤是地球生命的根基。按重量计，栖息于土壤之中的生物总量要多于地表之上的生物。土壤决定了可种植的作物、可修建的建筑以及可扎根生长的森林。该图层包含土壤化学变量有机碳密度（organic carbon density, OCD），其定义为碳质量与土壤体积的比值（即质量除以体积）。 据维多利亚州农业厅（Agriculture Victoria）的数据，土壤碳可通过矿化作用提供养分，有助于团聚土壤颗粒（维持土壤结构）以提升抗物理退化能力，增强微生物活性，提升土壤储水能力与植物可利用水量，并保护土壤免受侵蚀。 本图层为通用中型尺度全球预测性土壤图层，适用于全球制图与决策支持。全球诸多区域尚无土壤采样数据，因此本图层通过预测得到对应区域最可能的土壤参数。该预测由位于荷兰瓦赫宁根的ISRIC资助的soilgrids.org完成，共划分6个深度区间。每个250米分辨率的像素均包含由soilgrids.org基于全球最优可用数据预测得到的对应区域数值。 有机碳密度数据共涵盖6个深度区间，覆盖范围从地表至地下2米。各变量与深度区间均可通过图层的多维属性进行访问。 ## 数据集摘要 **制图现象**：单位为kg/m³的有机碳密度 **像元尺寸**：250米 **像元类型**：32位浮点型，由原始16位无符号整型在线数据转换得到 **坐标系**：Web墨卡托（Web Mercator）辅助球面坐标系，通过最邻近重采样从古德霍姆洛辛陆地投影（250米分辨率）转换而来 **覆盖范围**：除南极洲外的全球陆地面积 **可视比例尺**：全比例尺可见 **行列数**：160300 × 100498 **数据来源**：soilgrids.org **发布日期**：2020年5月 **分析适配说明**：本图层基于soilgrids.org的有机碳密度均值预测数据构建，以适配分析需求。您可通过6个深度区间之一访问有机碳密度数值：在地图客户端的多维选择器中选择深度变量即可选取对应区间。各深度区间参数如下： | 平均深度（cm） | 实际深度范围 | | ---- | ---- | | -2.5 | 0-5cm | | -10 | 5-15cm | | -22.5 | 15-30cm | | -45 | 30-60cm | | -80 | 60-100cm | | -150 | 100-200cm | ### 本图层应用场景 本图层适用于ArcGIS生态系统内的可视化与分析工作。您可将本图层与自有数据及ArcGIS世界生活地图集（ArcGIS Living Atlas of the World）中的其他图层结合，在ArcGIS Online与ArcGIS Pro中创建功能强大的Web地图，可单独使用，亦可集成于故事地图或其他应用程序中。 更多详情可参阅官方博客： 1. 《探索与发现：解读全球250米分辨率土壤图层》 2. 《ArcGIS世界生活地图集多维土壤图层快速上手》 由于本图层属于ArcGIS世界生活地图集的一部分，添加至地图的操作十分简便： - **在ArcGIS Online中添加**：选择「添加」→「浏览生活地图集图层」，打开窗口后在搜索框输入"world soils soilgrids"，浏览至目标图层后选中并点击「添加至地图」即可。 - **在ArcGIS Pro中添加**：打开地图后，在「地图」选项卡中选择「添加数据」，点击下拉菜单顶部的「数据」，在左侧弹出的「添加数据」对话框中，按需展开「门户」后选择「生活地图集」，在搜索框输入"world soils soilgrids"，浏览至目标图层后点击「确定」。 在ArcGIS Pro中，您可使用内置栅格函数或自定义函数，实现数据的定制化提取。影像图层可为Pro中的地理处理工具、模型或Python脚本提供高效且强大的输入源。在线环境下，您可通过过滤按钮与图层内置的栅格函数，筛选并展示数据子集。 本图层作为ArcGIS世界生活地图集的组成部分，为您探索景观图层及数百个主题下的优质权威地图提供了便捷途径。 ### 分析适配说明 若要使用本图层的分析优化功能，需由您所在的ArcGIS组织管理员启用该能力。有关启用此功能的更多信息，请参阅本文档「区域数据托管」章节。 分析优化意味着本图层不受分析尺寸限制，推荐与其他分析优化图层进行多源分析。完整的分析优化影像图层列表可参阅ArcGIS世界生活地图集「分析优化影像图层」群组。 ### 有关soilgrids图层的更多信息 多数常见问题可在soilgrids.org（ISRIC）的数据常见问题（FAQ）页面获取解答。 为制作本图层，Esri将ISRIC土壤网格数据的期望值从其原始投影（古德陆地投影，WKID 54052）通过最邻近重采样转换至Web墨卡托投影，以适配在线制图需求。Web墨卡托投影下的分辨率与原始投影一致，均为250米。请注意，本Web墨卡托版本是原始数据集经重投影得到的。 本多维土壤集合提供了soilgrids.org计算得到的各土壤变量的均值/期望值。若需获取土壤变量的其他分布数据，请直接从soilgrids.org下载。数据以VRT格式提供，您可在ArcGIS Pro中将其转换为其他影像格式。 ### 访问本图层的配套不确定性图层 由于全球范围内的数据质量存在差异，预测值的不确定性也随区域有所不同。本图层设有配套的不确定性图层，可用于评估您在地图中查看的数值的可靠性。在地图客户端的多维设置中选择变量与深度区间，即可访问该不确定性图层。