3. Example Analysis with Screenshots

      3.a
     

      Each pixel within a Cropland Data Layer has a category name, category value, and a defined color. The color and category name are also available within the Legend tab next to the Layer selection.

     

      3.b Define Area of Interest

      It is necessary to define an Area of Interest (AOI) in order to perform any analysis. There are four ways to select an AOI.

            3.b.iBy State/Agricultural Statistics District/County

            You can select an AOI by state, by Agricultural Statistics District within a state, or by County within a state. You can only select districts or counties within one state at a time.

           

            The selected area of interest will be highlighted.

           




            3.b.ii By Rectangle
           

            Click and drag to define rectangular AOI

           


            3.b.iii by Polygon
           

            To define a polygon area of interest, click around the boundary of the area. Double click to finish AOI.

           



            3.b.iv By Circle
           

            Start by clicking in the center of the circle and dragging outward.

           


      3.c Generate Statistics for Area of Interest

            Once an Area of Interest is selected, click on the Generate Statistics button to generate a table of categories within the AOI, the pixel counts of each category, and the resulting acreage calculated from the pixel count.

           


            For a visual representation of the table data click on the Pie Chart or the Histogram

                       


            To obtain a map of one or more categories within an Area of Interest click Export selected crop(s) for mapping. The example below maps potatoes and spring wheat pixels within Madison County, Idaho. Click the resulting download button to download the .tif file.
           

            Use the Zoom in button zoom into an area. Use the Zoom out or Refresh button to reset the preview image.

           

      3.d Change Analysis

            To perform a Change Analysis, select an Area of Interest and two Cropland Data Layers (CDLs) to compare. Once the AOI is selected click the Change Analysis button and enter the analysis years into the resulting window.
           

            The resulting table will detail how many pixels changed from one category to another between the two selected CDLs. In the change analysis table below 46,318 pixels (35,892.8 acres) of soybeans in 2007 changed to corn in 2009.

           



                  3.e.i Download a compressed file of all states for most recent year.

                  If no Area of Interest is selected, clicking the Download Defined Area of Interest button will provide the option to download a compressed file of CDLS for all the states.

                 


                  3.e.ii Download Defined Area of Interest Data into Google Earth for an Area of Interest

                  Select an Area of Interest to display in Google Earth. Click on the Download Defined Area of Interest Data button. In the resulting window, select the Cropland Data Layer years of interest. Multiple years may be selected. Click Submit.

                 

                  There are multiple projections to choose from. The default projection is USA Contiguous Albers Equal Area Conic USGS. Use the pull down menu to choose which projection is desired.
                 

                  Click Submit to select Downloading options.

                 


                  To preview all selected CDLs, click button. Using this button allows you to click through each year selected using the tabs at the top of the window.

                 



                  To import into Google Earth, click to download the .kml file required to load into Google Earth.
                  If Google Earth is running, select Open to download directly into Google Earth.