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Once the mosaic is successfully run in PEDITOR,
it is exported into Erdas Imagine .LAN format, to prepare for public
distribution.
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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.
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The Cropland Data Layer DVD products contain
two years (if available) of imagery in two different image formats.
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GeoTiff format and .IMG format (winzip
compression).
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The category colors are held consistent across
each state each year
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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.
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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.
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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.
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