State-wide CDL
 Distribution
lHeld until county estimates released
lBundle images with ESRI’s ArcReader
–Ancillary vector layers
–Area Sampling Frame where available
lNo copyright restrictions
lPublish accuracy statistics
l
•All CDL distribution for the previous crop year is held until the release of the official NASS county estimates for the major commodities grown within a given state.
•Corn and Soybeans are released in March for the previous crop year – Midwestern States
•Rice and Cotton are released in June for the previous crop year – Delta States
•A freeware browser “ArcReader” from ESRI is bundled onto the DVD, allowing users without a GIS or image processing software package to be able to view the CDL products.
•A demo ArcReader project is on the root directory of each CDL CD called “PublishedMapDocuments”.  The file has a .pmf file extension.  Once loaded, the categorized image appears in the main window, and contains themes from the National Atlas program, also included are NASS Agricultural Statistical Districts boundaries, and Area Sampling Frame.
•For users who have ESRI’s ArcGIS installed on their Desktop a \MapDocuments folder contains a .mxd project.
•The shapefiles and images on this DVD are under no copyright restrictions, as they are considered in the public domain.
•If you choose to reuse and publish any of the data this DVD, NASS would appreciate acknowledgment or credit for the usage of the categorized imagery.
•NASS publishes all available accuracy statistics for end-user viewing.
•The Percent Correct is calculated for each cover type in the ground truth information, it shows how many of the total pixels were correctly classified (i.e. across all cover types).
•“Commission Error” is the calculated percentage of all pixels categorized to a specific cover type that were not of that cover type in the ground truth (i.e. incorrectly categorized).
•CAUTION: a quoted Percent Correct for a specific cover type is worthless unless accompanied by its respective Commission Error.
•Example: if you classify every pixel in a scene to “wheat”, then you have a 100% correct wheat classifier (its Commission Error is also almost 100%).
•The “Kappa Statistic” is an attempt to adjust the Percent Correct using information gained from the confusion matrix for that cover type.
•Many remote sensing groups use the Percent Correct and/or Kappa statistics as their final measure of classification accuracy.