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•Landsat observes the earth in a near polar
orbit, and covers the same spot on earth every 16 days. The combination of
Landsat 5 & 7 synchronized in a 8 day repeat cycle greatly increases the
probability of full state coverage during the growing season.
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•NASS uses seven Landsat TM/ETM+ bands,
systematic correction, 30 meter resolution, path/row orientation, and nearest
neighbor resampling.
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•In many cases, it is very difficult to obtain
full state cloud free imagery during the growing season, even with two
Landsat satellites, therefore, losing one would be very detrimental to the
program. However, adding a third or
more Landsat like sensors would greatly increase the odds of obtaining cloud
free imagery during the growing season.
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•The Landsat 7 covers the next adjacent path
that the Landsat 5 covered the previous day, so that path 30 is observed on a
Friday by Landsat 5, then on Saturday Landsat 7 observes adjacent path 31.
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•The medium resolution Landsat platform provides
excellent results not only because of the temporal coverage but because of
spectral properties of the available bands, and how effective they are in
separating land cover.
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