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This is a full classified scene based on the
clustering of the training segments.
This classification was derived from a multi-temporal scene observed
6/10 and 9/6 in 2002.
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For estimation purposes, clouds are minimized
by defining Analysis Districts along adjacent scene edges, by cutting the
Analysis Districts by county boundary, or cutting out the clouds out by
primary sampling units.
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Several factors can lead to problems in a
classification, some get corrected in early edits and some do not:
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Poor imagery dates, with respect to the major
crops of interest; this may not be correctable.
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Complete training fields that are incorrectly
identified in the ground truth.
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Parts of training fields that are not the same
as the major crop or cover type.
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Irrigation ditches, wooded areas, low spots
filled with water.
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Bare soil areas in an otherwise vegetated
field.
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Other waste areas, grassy waste fields and
idle cropland.
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Crops that look alike to the algorithm(s) due
to planting/growing cycle:
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Small grains in general.
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Crops in senescence.
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Cover types that are essentially the same but
used differently:
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Wooded pasture versus woods or waste fields
(only difference may be the presence of livestock).
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Corn for grain versus corn silage.
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Cover crops such as rye and oats.
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Cover types that change signatures back and
forth during the growing season.
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Alfalfa and other hays before and after
cutting, with multiple cuttings per year.
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