World Soils 250m Soil Organic Carbon

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 soil organic carbon (soc) which measures the mass of carbon in proportion to the mass of the soil. (mass divided by mass.) 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 soil organic carbon 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: Soil organic carbon content in the fine earth fraction in g/kg 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 soc were used to create this layer. You may access soil organic carbon 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，生存于土壤中的生物总量远超生长于土壤表面的生物。土壤决定了可种植的作物、可建造的构筑物，以及可扎根生长的森林。该图层包含化学土壤变量土壤有机碳（soil organic carbon, SOC），其定义为土壤中碳质量与土壤总质量的比值（即质量除以质量）。 据维多利亚州农业厅（Agriculture Victoria）介绍，土壤碳可通过矿化作用提供养分，有助于团聚土壤颗粒以维持土壤结构，提升抗物理退化能力，增强微生物活性，提高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。由于全球许多区域尚无土壤采样数据，本图层通过预测给出对应区域最可能的土壤有机碳含量。该预测由位于荷兰瓦赫宁根的国际土壤参考与信息中心（ISRIC）资助的soilgrids.org完成，共划分6个深度范围。每个250米分辨率的像元均包含基于全球最优可用数据预测得到的对应区域数值。土壤有机碳数据按6个深度范围提供，覆盖从地表至地下2米的土层。各变量与深度范围可通过图层的多维属性进行访问。 ### 数据集摘要 **映射现象**：细土组分中的土壤有机碳含量，单位为克/千克（g/kg） **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而来 **坐标系**：Web Mercator辅助球面投影（Web Mercator Auxiliary Sphere），通过最邻近重采样从古德霍姆洛辛陆地投影（250米分辨率，Goode's Homolosine Land）转换得到 **覆盖范围**：除南极洲外的全球陆地面积 **可见比例尺**：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的土壤有机碳均值预测结果进行分析优化。您可通过6个深度范围之一获取土壤有机碳数值：在地图客户端的多维选择器中选择深度变量即可指定目标范围。各深度对应的平均深度与实际范围如下： 平均深度（厘米） | 实际深度范围 -2.5 | 0-5厘米 -10 | 5-15厘米 -22.5 | 15-30厘米 -45 | 30-60厘米 -80 | 60-100厘米 -150 | 100-200厘米 ### 图层应用场景 本图层适用于ArcGIS体系下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）中的其他图层相结合，在ArcGIS Online（ArcGIS Online）与ArcGIS Pro（ArcGIS Pro）中创建功能强大的Web地图，既可单独使用，也可嵌入故事地图或其他应用程序。 更多详情可参阅我们的博客文章： 1. 《探索与发现：解析全球250米分辨率土壤图层》 2. 《在ArcGIS世界生活地图集中使用多维土壤图层入门指南》 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」，弹出窗口后在搜索框中输入"world soils soilgrids"，浏览至目标图层后选中并点击「添加至地图」。 - 在ArcGIS Pro中添加：打开地图并选择「地图」选项卡中的「添加数据」，在下拉菜单顶部选择「数据」，此时左侧将弹出「添加数据」对话框，如有需要请展开「门户」选项并选择「生活地图集」，在搜索框中输入"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对数据进行定制化提取。影像图层可为ArcGIS 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。在在线平台中，您可通过过滤按钮与图层内置的栅格函数筛选图层以显示数据子集。 本图层是世界生活地图集的组成部分，该地图集提供了便捷的途径以探索各类景观图层及数百个主题下的精美权威地图。 ### 分析优化说明 如需使用本图层的分析优化功能，需由您所在的ArcGIS组织管理员启用该功能。有关启用该功能的更多信息，请参阅本文档「区域数据托管」部分。 分析优化意味着本图层无分析尺寸限制，推荐与其他分析优化图层配合进行多源分析。有关所有分析优化影像图层的完整列表，请参阅ArcGIS世界生活地图集：分析优化影像图层群组。 ### 更多soilgrids图层相关信息 多数常见问题可在soilgrids.org（ISRIC）的数据常见问题解答（FAQ）页面中找到答案。 为制作本图层，Esri将ISRIC土壤网格数据的期望值从soilgrids的源投影（古德霍姆洛辛陆地投影，WKID 54052）通过最邻近重采样转换至Web Mercator投影，以适配在线制图需求。Web Mercator投影下的分辨率与原始投影一致，均为250米。请注意，本Web Mercator版本是对原始数据集进行重投影后得到的。 本多维土壤集合提供了由soilgrids.org计算得到的各土壤变量的均值或期望值。如需获取土壤变量的其他分布数据，请直接从soilgrids.org下载原始数据。数据以虚拟栅格模板（VRT）格式提供，您可在ArcGIS Pro中将其转换为其他影像格式。 ### 配套不确定性图层访问 由于全球各地的数据质量存在差异，预测值的不确定性也因区域而异。本图层配有配套的不确定性图层，可用于验证您在本地图中查看的数值以支持分析工作。您可在地图客户端的多维设置中选择变量与深度范围，以访问配套的不确定性图层。