1. Layers

      -Background Layers
            - Global Land Cover - A visual background image. Including the Global Land Cover will not affect any calculations or analysis.

      -Cropland Data Layers
            - 1997 - 2012 - only 1 year can be selected at one time. Changes to the selection can be made multiple times. The Cropland Data Layers for some states are not available for certain years.

      -Crop Mask Layer
            - The crop mask layer is generated from the Cropland Data Layers from 2010 to 2014.

      -Boundary Layers
            - CONUS Counties
            - CONUS Agricultural Statistics Districts (ASDs)
            - CONUS States

      -Water Layers
            - Rivers at the national and regional level
            - Lakes at the national and regional level

      -Road Layers
            - National freeway system
            - Major highways at the regional level