Erdas Enhancement
lImport categorized mosaic (.LAN) to .img
–Re-build statistics
–Add class names
–Re-build projection metadata
–Clip to state boundary
–Colorize categories
lMaximize contrast between crops
lColors maintained within state
lCategory DN’s consistent across all states
–Export to GeoTiff
l
•Once the mosaic is successfully run in PEDITOR, it is exported into Erdas Imagine .LAN format, to prepare for public distribution.
•It is then necessary to rebuild the image statistics, add color/class name metadata, build pyramid layers, rebuild the projection information, and clip to state boundary.
•The Cropland Data Layer DVD products contain two years (if available) of imagery in two different image formats.
•GeoTiff format and .IMG format (winzip compression).
•The category colors are held consistent across each state each year
•The category digital numbers DN are consistent across each state, so that corn will always be DN 1, and soybeans will always be DN value 5, in all states for all years.
•The CDL images are available in GeoTIFF and ERDAS Imagine .img formats.  The latest two years worth of images are available on the DVD, size limitations prohibit adding additional years.  Each CDL DVD was ortho-rectified to 50 meters RMS, unless noted, this allows for precise comparisons of field and crop changes/rotations over time.
•The latest CDL products are available once the official NASS county estimates are released.  So for any given crop year, the CDL will be available the following March or June depending when the major commodities within a particular state are released.