World Soils 250m Bulk 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 physical soil variable bulk density (bdod). From USDA: Bulk density is an indicator of soil compaction. It affects infiltration, rooting depth, available water capacity, soil porosity and aeration, availability of nutrients for plant use, and activity of soil micro-organisms, all of which influence key soil processes and productivity. 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 bulk 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: Bulk density of the fine earth fraction in kg/dm³ 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 bdod were used to create this layer. You may access bulk 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. 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. 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 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 Living Atlas Imagery Layers Optimized for Analysis 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。按生物量计算，栖息于土壤中的生物总量远超地表之上的生物。它决定了可种植的作物类型、可建造的构筑物形式，以及森林能否扎根生长。 本数据集图层包含土壤物理变量**容重（bulk density, bdod）**。据美国农业部（USDA）定义：容重是土壤压实程度的指示指标。它会影响土壤入渗、根系深度、有效持水量、土壤孔隙度与通气性、植物可利用养分的有效性，以及土壤微生物活性，所有这些均会影响核心土壤过程与土壤生产力。 本图层为通用中尺度全球预测性土壤图层，适用于全球制图与决策支持工作。全球诸多区域尚无土壤采样数据，因此本地图通过预测给出对应点位最可能的土壤容重值。该预测由荷兰瓦赫宁根的国际土壤参考与信息中心（ISRIC）资助的soilgrids.org平台生成，共涵盖6个深度区间。每个250米分辨率的像素点均包含soilgrids.org基于全球最优可用数据，为对应区域预测得到的容重值。 容重数据按从地表至地下2米的6个深度区间提供，可通过图层的多维属性获取任意变量与深度区间的数据。 ## 数据集摘要 制图对象：细土组分容重，单位为kg/dm³ 像元分辨率：250米 像元类型：32位浮点型，由原始在线数据（16位无符号整型）转换而来 坐标系：Web墨卡托辅助球面坐标系，从古德同源分瓣陆地投影（250m分辨率）通过最近邻法重投影得到 覆盖范围：除南极洲外的全球陆地范围 显示比例尺：全比例尺可见 行列数：160300行，100498列 数据源：Soilgrids.org 发布日期：2020年5月 分析适配说明：本图层基于soilgrids.org平台针对bdod生成的平均预测值，经分析优化处理后制作而成。 用户可获取6个深度区间中的任意一个容重数据：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区间。各深度区间的参数对应关系如下： - 平均深度（cm）：-2.5 → 实际深度范围：0-5cm - 平均深度（cm）：-10 → 实际深度范围：5-15cm - 平均深度（cm）：-22.5 → 实际深度范围：15-30cm - 平均深度（cm）：-45 → 实际深度范围：30-60cm - 平均深度（cm）：-80 → 实际深度范围：60-100cm - 平均深度（cm）：-150 → 实际深度范围：100-200cm ## 本图层应用场景 可在ArcGIS生态系统中实现可视化与分析工作。本图层可与用户自有数据及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中创建功能强大的网页地图，可独立使用，或集成于故事地图及其他应用程序中。 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： 1. 在ArcGIS Online中，依次选择「添加」→「浏览生活地图集图层」，将弹出窗口。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」即可。 2. 在ArcGIS Pro中，打开地图后选择「地图」选项卡下的「添加数据」，在下拉菜单顶部选择「数据」，将弹出「添加数据」对话框。若需展开门户内容，请先展开「Portal」选项，随后选择「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」即可。 在ArcGIS Pro中，用户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。在线环境中，用户可通过过滤按钮与图层内置栅格功能，筛选并显示数据子集。 本图层属于ArcGIS世界生活地图集，该图集为用户提供了便捷途径，可探索景观图层及数百个主题下的诸多优质权威地图。更多详情可参阅官方博客： - 发现与启示：探索全球250米分辨率土壤图层 - ArcGIS世界生活地图集中的多维土壤图层快速入门 ## 分析适配说明 若需使用本图层的分析优化功能，需由ArcGIS组织管理员启用该能力。有关启用此功能的更多细节，请参阅本文档「区域数据托管」章节。分析优化意味着本图层无分析尺寸限制，推荐与其他已优化的图层结合开展多源分析。可参阅「针对分析优化的生活地图集影像图层」群组，获取所有已优化分析的影像图层完整列表。 有关soilgrids图层的更多信息，以及常见问题解答，可访问soilgrids.org（ISRIC）平台的数据常见问题（FAQ）页面获取。 本图层的制作过程：Esri将ISRIC土壤网格数据的期望值，从soilgrids的源投影（古德陆地投影，WKID 54052）通过最近邻法重投影至Web墨卡托坐标系，以适配在线制图需求。Web墨卡托坐标系下的分辨率与原始投影一致，均为250米。请注意，本Web墨卡托版本是通过对原始数据集重投影得到的。 本多维土壤数据集提供了soilgrids.org平台计算得到的各土壤变量的均值或期望值。若需获取土壤变量的其他分布形式数据，请直接从soilgrids.org平台下载。数据以VRT格式提供，可在ArcGIS Pro中转换为其他影像格式。 ## 访问本图层的配套不确定性图层 由于全球各地数据质量存在差异，预测值的不确定性也随区域不同而变化。本图层配套有不确定性图层，可用于量化分析中地图显示的数值可靠性。在地图客户端的多维设置中选择变量与深度，即可访问配套不确定性图层。