USA SSURGO - Erosion Class

Erosion, the loss of soil due to the effects of water and wind, leads to serious degradation of lands and the loss of agricultural productivity. This layer rates erosion in the past tense, i.e. how much of the original topsoil has been lost in each map unit. What time frame is implied for the soil loss? We asked Bob Dobos, soil scientist - interpretations at the National Soil Survey Center that question. Here is what he writes: "Accelerated erosion, either by wind or water, is caused typically by the activities of humans. We try to estimate the degree of erosion, but that can be dicey because of possible lack of an uneroded state. The timing of the erosion is not something that we try to establish. In my opinion, what is being observed is the degree of erosion since the first time the soil was farmed, perhaps 500 years or so in some places, much more recent in others. Since the observation of a soil is a snapshot in time, the rate of erosion or the time zero of erosion is not considered. Natural erosion also occurs as is evidenced by the Grand Canyon or the Channeled Scablands. I have never worked in an area that has visible evidence of natural erosion." This layer classifies the amount of soil loss in the top soil layers in 5 classes: None: Area of soil deposition. Class 1: In this map unit,1 to 25 percent of the original topsoil has been lost to erosion. Class 2: In this map unit, 25 to 75 percent of the original topsoil has been lost to erosion. Class 3: In this map unit, 75 to 99 percent of the original topsoil has been lost to erosion. Class 4: In this map unit, all of the original topsoil has been lost to erosion. Dataset Summary Phenomenon Mapped: Top soil loss due to erosion Geographic Extent: Contiguous United States, Alaska, Hawaii, Puerto Rico, Guam, US Virgin Islands, Northern Mariana Islands, Republic of Palau, Republic of the Marshall Islands, Federated States of Micronesia, and American Samoa. Projection: Web Mercator Auxiliary Sphere Data Coordinate System: WKID 5070 USA Contiguous Albers Equal Area Conic USGS version (contiguous US, Puerto Rico, US Virgin Islands), WKID 3338 WGS 1984 Albers (Alaska), WKID 4326 WGS 1984 Decimal Degrees (Guam, Republic of the Marshall Islands, Northern Mariana Islands, Republic of Palau, Federated States of Micronesia, American Samoa, and Hawaii). Units: Classes Cell Size: 30 meters Source Type: Discrete Pixel Type: Unsigned integer Source: Natural Resources Conservation Service Update Frequency: Annual Publication Date: December 2025 Data from the gNATSGO database was used to create the layer. This layer is derived from the 30m rasters produced by the Natural Resources Conservation Service (NRCS). The value is derived from the gSSURGO component table field Erosion Class (erocl). The value in this layer is the dominant condition found within the map unit. What can you do with this layer? This layer is suitable for both visualization and analysis acrossthe 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: Analyzing Soil Capability for Agriculture in the Living Atlas of the World Working with Soil Data from the Living Atlas in ArcGIS Pro 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 "erosion class" 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 "erosion class" 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. The ArcGIS Living Atlas of the World provides an easy way to explore many other beautiful and authoritative maps on hundreds of topics like this one. Questions? Please leave a comment below if you have a question about this layer, and we will get back to you as soon as possible.土壤侵蚀（Erosion）是指因水蚀与风蚀作用导致的土壤流失现象，会引发土地严重退化与农业生产力锐减。本图层以过去时态评估侵蚀程度，即每个制图单元中原始表层土壤的流失量。那么土壤流失的隐含时间范围为何？我们就此问题咨询了国家土壤调查中心（National Soil Survey Center）负责解译工作的土壤科学家鲍勃·多博斯（Bob Dobos），其回复如下：“由风或水引发的加速侵蚀，通常由人类活动所致。我们尝试估算侵蚀程度，但由于可能不存在未受侵蚀的基准状态，这一过程颇具难度。我们并未试图确定侵蚀发生的具体时间节点。在我看来，当前观测到的侵蚀程度是自土壤首次被耕作以来的累积结果——部分地区可追溯至约500年前，其他地区则时间更近。由于土壤观测只是某一时刻的快照，我们并未考量侵蚀速率或侵蚀起始时间。自然侵蚀同样存在，例如大峡谷（Grand Canyon）与水道疤痕地（Channeled Scablands）便是明证。我从未在存在明显自然侵蚀迹象的区域开展过工作。” 本图层将表层土壤流失量划分为5个等级： - 无（None）：发生土壤沉积的区域。 - 等级1：该制图单元中，原始表层土壤有1%~25%因侵蚀而流失。 - 等级2：该制图单元中，原始表层土壤有25%~75%因侵蚀而流失。 - 等级3：该制图单元中，原始表层土壤有75%~99%因侵蚀而流失。 - 等级4：该制图单元中，原始表层土壤已完全因侵蚀而流失。 ### 数据集摘要 #### 制图现象：侵蚀引发的表层土壤流失 #### 地理覆盖范围：美国本土、阿拉斯加州、夏威夷州、波多黎各、关岛、美属维尔京群岛、北马里亚纳群岛、帕劳共和国、马绍尔群岛共和国、密克罗尼西亚联邦和美属萨摩亚。 #### 投影：Web墨卡托辅助球面 #### 数据坐标系： - WKID 5070：美国本土连续等面积阿尔伯斯投影（美国本土、波多黎各、美属维尔京群岛） - WKID 3338：WGS 1984阿尔伯斯投影（阿拉斯加） - WKID 4326：WGS 1984十进制度（关岛、马绍尔群岛共和国、北马里亚纳群岛、帕劳共和国、密克罗尼西亚联邦、美属萨摩亚及夏威夷） #### 单位：等级 #### 像元大小：30米 #### 数据源类型：离散型 #### 像元类型：无符号整数 #### 数据来源：美国自然资源保护局（Natural Resources Conservation Service, NRCS） #### 更新频率：年度更新 #### 发布日期：2025年12月 本图层基于gNATSGO数据库制作而成，源自美国自然资源保护局（NRCS）生成的30米栅格数据。其数值取自gSSURGO组件表的侵蚀等级（Erosion Class, erocl）字段，图层数值代表制图单元内占主导地位的侵蚀状况。 本图层适用于ArcGIS系统内的可视化与分析工作。可在ArcGIS Online与ArcGIS Pro中，将本图层与自有数据及ArcGIS世界生活地图集（ArcGIS Living Atlas of the World）的其他图层相结合，制作可独立使用、或用于故事地图及其他应用场景的高性能Web地图。详细信息可参阅以下博客： 1. 《在世界生活地图集中开展农业土壤承载力分析》 2. 《在ArcGIS Pro中使用生活地图集土壤数据》 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. **ArcGIS Online**：选择「添加」→「浏览生活地图集图层」，打开窗口后在搜索框输入“侵蚀等级”，浏览并找到目标图层，选中后点击「添加至地图」即可。 2. **ArcGIS Pro**：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」，左侧将弹出「添加数据」对话框，必要时展开「门户」选项并选择「生活地图集」，在搜索框输入“侵蚀等级”，浏览找到目标图层后点击「确定」。在ArcGIS Pro中，可使用内置栅格工具或自定义工具，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Web端，可通过筛选按钮与图层内置的栅格函数，对图层进行过滤以显示数据子集。 ArcGIS世界生活地图集提供了便捷途径，可探索数百个主题下的众多优质权威地图，本图层即为其中一例。如有任何关于本图层的疑问，请在下方留言，我们将尽快回复。