The 2020 Cropland Data Layer (CDL) was released Feb 1, 2021, and Kansas State Statistician Doug Bounds then created 105 downloadable county maps and made them available on the KSU Ag Manager site in March.
The Cropland Data Layer is a crop-specific land cover classification product of USDA-NASS, with more than 100 crop categories grown in the United States. CDLs are derived using a supervised land cover classification of satellite imagery. The supervised classification relies on first manually identifying pixels within certain images, often called training sites, which represent the same crop or land cover type. Using these training sites, a spectral signature is developed for each crop type that is then used by the analysis software to identify all other pixels in the satellite image representing the same crop. Using this method, a new CDL is compiled annually and released to the public a few months after the end of the growing season through the online CropScape data portal.