Water Related Land Use Statewide (2021) (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 2.9.2 with USDA NAIP 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.点击此处获取文件地理数据库（File Geodatabase，.gdb），其中包含用于生成数据集的相关文件；点击此处获取最终报告、完整文档与元数据。 要素类（Feature Class）将被加载至平板电脑，野外作业人员会针对选定的部分田块或多边形矢量要素，标注其作物类型、土地覆被类型与灌溉方式。每台平板电脑均配套全球定位系统（Global Positioning System，GPS）设备，可在野外标注流程中实时追踪，持续更新野外作业人员的位置。 本流程依托ArcPro 2.9.2将数字化成果存储为地理数据库要素类，以美国农业部（United States Department of Agriculture，USDA）国家农业影像计划（National Agriculture Imagery Program，NAIP）影像作为底图，并叠加其他参考图层。将对单个农田、城市区域等现有田块边界进行精准数字化更新，并在该流程中记录灌溉类型与土地利用方式的变更。 将下载对应年份的美国农业部（USDA）国家农业统计服务局（National Agricultural Statistics Service，NASS）作物数据层（Cropland Data Layer，CDL）栅格数据，数据来源为https://nassgeodata.gmu.edu/CropScape/。 使用分区统计（Zonal Statistics）地理处理工具，基于CDL数据为多边形矢量要素赋予更新后的作物类型属性。随后，数据集将经过多轮与历史清查数据的对比及质量检查流程，以确定并生成最终属性信息。 ### 属性字段说明 土地利用类型（Landuse）：通用土地覆被分类体系，用于区分土地利用方式，具体包括： - 农业用地（Agriculture）：用于作物种植或畜牧养殖的管理用地； - 其他用地（Other）：野生用地的宽泛分类； - 河岸/湿地（Riparian/Wetland）：受高地下水位影响的野生区域，通常紧邻地表水体； - 城市用地（Urban）：已开发区域，包含公园等城市绿地； - 水体（Water）：地表水体，如滩涂、溪流与湖泊。 作物组别（CropGroup）：针对更广范围的作物类别进行的分组，以便快速查询所有果园、谷物类作物等相关类型。 描述字段（Description）：用于描述或标识通过地理信息系统（Geographic Information System，GIS）流程确定的各类作物类型与土地利用类型的属性字段。 灌溉方式（IRR_Method）：沿用自2015年结束的全州野外调查结果，并基于影像数据与年度野外核查进行更新的作物灌溉方式，具体包括： - 滴灌（Drip）：通过输水管道将水缓慢释放至作物表层或地下的灌溉方式； - 旱作（Dry Crop）：该农业用地未施加人工灌溉，作物依靠自然过程获取水分； - 漫灌（Flood）：从作物上方的沟渠或管道引水，以足够水量淹没灌溉地块的灌溉方式； - 无灌溉（None）：对应非农业用地； - 喷灌（Sprinkler）：通过移动或固定喷头将水喷洒至作物上方的灌溉方式； - 地下水位补给灌溉（Sub-irrigated）：该地块未施加人工灌溉水，但因地下水位较高自然获得充足水分，通常紧邻河岸区域。 面积（Acres）：多边形矢量要素的计算面积，单位为英亩。 所属州（State）：多边形矢量要素所在的州。 所属县（County）：多边形矢量要素所在的县。 流域（Basin）：多边形矢量要素所在的水文流域，与6级水文单元代码（Hydrologic Unit Code，HUC 6）密切相关。该流域边界由DWRe划定，为便于管理纳入了存在跨流域径流的其他流域部分区域。 子流域（SubArea）：多边形矢量要素所在的子流域，与8级水文单元代码（HUC 8）密切相关。子流域为DWRe划定的大型水文流域的次级分区。 标签类别（Label_Class）：处理过程中由Label与Class_Name字段组合生成的属性，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同类作物或"Other"作物。 简称标签（LABEL）：针对各作物描述与灌溉类型的简写标识。 类别名称（Class_Name）：多边形要素内USDA CDL CropScape栅格图层中的多数像元值，可能与最终作物判定结果（Description）存在差异。 旧土地利用类型（OldLanduse）：与Landuse类似，但会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。 土地利用组别代码（LU_Group）：该代码代表部分内部分组，可用于符号化制作与其他汇总分析工作。 调查年份（SURV_YEAR）：用于标识数据集对应的年份或生长季。