Water Related Land Use Statewide (2020) (Features)

For a file geodatabase (.gdb) Click Here (includes files used to create data). For the final report, full documentation, and metadata Click Here. Feature Classes are loaded onto tablet PCs and Field crews are sent to label the crop or land cover type and irrigation method for a subset of select fields or polygons. Each tablet PC is attached to a GPS unit for real-time tracking to continuously update the field crew’s location during the field labeling process. Digitizing is done as Geodatabase feature classes using ArcPro 2.6.3 with Sentinel imagery as a background with other layers added for reference. Updates to existing field boundaries of individual agricultural fields, urban areas and more are precisely digitized. Changes in irrigation type and land use are noted during this process. Cropland Data Layer (CDL) rasters from the United States Department of Agriculture (USDA) National Agricultural Statistics Service (NASS) are downloaded for the appropriate year. https://nassgeodata.gmu.edu/CropScape/ Zonal Statistics geoprocessing tools are used to attribute the polygons with updated crop types from the CDL. The data is then run through several stages of comparison to historical inventories and quality checking in order to determine and produce the final attributes. Attributes Landuse– A general land cover classification differentiating how the land is used Agriculture: Land managed for crop or livestock purposes Other: A broad classification of wildland Riparian/Wetland: Wildland influenced by a high water table, often close to surface water Urban: Developed areas, includes urban greenspace such as parks. Water: Surface water such as wet flats, streams, and lakes. CropGroup– Groupings of broader crop categories to allow easy access to or query of all orchard or grain types etc. Description– Attribute that describes/indicates the various crop types and land use types determined by the GIS process. IRR_Method– Crop Irrigation Method carried over from statewide field surveys ending in 2015 and updated based on imagery and yearly field checks. Drip: Water is applied through lines that slowly release water onto the surface or subsurface of the crop Dry Crop: No irrigation method is applied to this agricultural land, the crop is irrigated via natural processes. Flood: Water is diverted from ditches or pipes upland from the crop in sufficient quantities to flood the irrigated plot None: Associated with non-agricultural land Sprinkler: Water is applied above the crop via sprinklers that generally move across the field. Sub-irrigated: This land does not have irrigation water applied, but due to a high water table receives more water, and is generally closely associated with a riparian area Acres– Calculated acreage of the polygon. State– State where the polygons are found. County– County where the polygons are found. Basin– The hydrologic basin where the polygons are found, closely related to HUC 6. These basin boundaries were created by DWRe to include portions of other basins that have inter-basin flows for management purposes. SubArea– The subarea where the polygons are found, closely related to the HUC 8. Subareas are subdivisions of the larger hydrologic basins created by DWRe. Label_Class– Combination of Label and Class_Name fields created during processing that indicates the specific crop, irrigation, and whether the CDL classified the land as a similar crop or an “Other” crop. LABEL– A shorthand descriptive label for each crop description and irrigation type. Class_Name– The majority pixel value from the USDA CDL Cropscape raster layer within the polygon, may differ from final crop determination (Description). OldLanduse– Similar to Landuse, but splits the agricultural land further depending on irrigation. Pre-2017 datasets defined this as Landuse. LU_Group– These codes represent some in-house groupings that are useful for symbology and other summarizing. SURV_YEAR– Indicates which year/growing season the data represents.文件地理数据库（File Geodatabase, .gdb）请点击此处（包含用于创建数据集的源文件）。最终报告、完整文档及元数据请点击此处。 将地理数据库要素类加载至平板电脑，野外作业人员前往选定的部分田块或多边形区域，标注作物或土地覆盖类型与灌溉方式。每台平板电脑均搭载GPS定位单元，实现实时追踪，在野外标注过程中持续更新作业人员的位置信息。数字化工作以地理数据库要素类的形式开展，依托ArcPro 2.6.3完成，采用Sentinel影像作为底图，并叠加其他参考图层辅助判读。对单个农田、城区等现有田块边界开展精准数字化更新，同步记录灌溉类型与土地利用的变化情况。 从美国农业部（United States Department of Agriculture, USDA）下属国家农业统计服务中心（National Agricultural Statistics Service, NASS）获取对应年份的农田数据图层（Cropland Data Layer, CDL）栅格数据，下载地址为：https://nassgeodata.gmu.edu/CropScape/。使用分区统计（Zonal Statistics）地理处理工具，为多边形要素赋予CDL更新后的作物类型属性。随后将数据集与历史清查数据开展多阶段比对，并进行质量核查，以确定并生成最终属性信息。 ### 属性字段说明 1. Landuse（土地利用类型）：通用土地覆盖分类，用于区分土地利用方式： - Agriculture（农业用地）：用于作物种植或畜牧生产的管理土地 - Other（其他用地）：野生自然用地的宽泛分类 - Riparian/Wetland（河岸/湿地）：受高地下水位影响的野生区域，通常紧邻地表水区域 - Urban（城区）：开发建设区域，包含公园等城市绿地 - Water（水体）：地表水，如浅滩、溪流与湖泊 2. CropGroup（作物组）：更宽泛的作物类别分组，便于快速查询所有果园、谷物等类型的作物集合 3. Description（描述信息）：通过GIS流程确定的各类作物与土地利用类型的详细描述/标识属性 4. IRR_Method（灌溉方式）：源自2015年结束的全州田间调查的作物灌溉方式，并基于影像数据与年度田间核查进行更新。具体类型包括： - Drip（滴灌）：通过输水管道缓慢向作物地表或地下释水的灌溉方式 - Dry Crop（旱地作物）：未施加人工灌溉，作物依靠自然降水或自然水分补给的农用地 - Flood（漫灌）：从作物上游沟渠或管道引水，足量淹没灌溉地块的灌溉方式 - None（无灌溉）：对应非农业用地 - Sprinkler（喷灌）：通过田间移动喷头向作物上方喷水的灌溉方式 - Sub-irrigated（浸润灌溉/地下灌溉）：未人工施加灌溉水，但因高地下水位获得充足水分补给，通常与河岸区域密切相关的用地 5. Acres（面积）：多边形要素的计算英亩面积 6. State（州）：多边形要素所在的州 7. County（县）：多边形要素所在的县 8. Basin（水文流域）：多边形要素所在的水文流域，与HUC 6水文分区密切相关。该流域边界由DWRe制定，纳入了因跨流域流动需纳入统一管理的其他流域区域 9. SubArea（子流域）：多边形要素所在的子流域，与HUC 8水文分区密切相关。子流域是DWRe划分的大型水文流域的次级分区 10. Label_Class（标签类别）：处理过程中生成的Label与Class_Name字段组合，用于标识具体作物类型、灌溉方式，以及CDL是否将该地块归类为相似作物或“其他”类作物 11. LABEL（简写标签）：每种作物描述与灌溉类型的简写标识 12. Class_Name（类别名称）：多边形内USDA CDL Cropscape栅格图层的多数像元值，可能与最终作物判定结果（Description）存在差异 13. OldLanduse（旧土地利用类型）：与Landuse类似，但根据灌溉方式进一步细分农业用地。2017年之前的数据集将该字段定义为Landuse 14. LU_Group（土地利用分组代码）：该代码代表部分内部自定义分组，可用于符号化制图及其他汇总分析场景 15. SURV_YEAR（调查年份）：标识数据集对应的年份或生长季