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 ArcMap 10.X with NAIP or Google 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.
LUID -Unique ID number for each polygon in the final dataset, matches object.
Landuse - Land use type, similar to land cover and represents our own categories of how the land is used.
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 Methods.
Acres - Calculated acreage of the polygon.
State - Spatial intersection identifying the State where the polygons are found.
County - Spatial intersection identifying the County where the polygons are found.
Basin - Spatial intersection identifying the Basin where the polygons are found. Basins, or Utah Hydrologic Basins are large watersheds created by DWRe.
SubArea - Spatial intersection identifying the Subarea where the polygons are found. 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 specific cover and use types.
LABEL - Old shorthand descriptive label for each crop and irrigation type or land use type.
Class_Name - Zonal Statistics majority value derived from the USDA CDL Cropscape raster layer, may differ from final crop determination.
OldLanduse - This is the old short code found under landuse in past datasets and is kept to maintain connectivity with historical data.
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. Is useful when comparing to past layers.