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Last Post 20 Apr 2007 12:05 PM by  anon
FLAASH: Advanced settings
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anon



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20 Apr 2007 12:05 PM
    Hi all, Following my last post, I am now correcting, the ASTER Radiance imagery using FLAASH. I have all the correct settings and through trial and error have identified the optimal 'Output Scale Reflectance Factor' value to be 10. The manual suggests a value of 10 000. When I use 10 000 I get an image that looks nothing like the input data, however, when the value of 10 is used the image resembles the input with output values ranging from around 10 to above 50 but no more than 90. Is their a quantitative method of determining the optimal reflectance factor? Many thanks, Wesley

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    20 Apr 2007 12:05 PM
    Hi Wesley, The best way to tell what conversion factor to use is to look at the units assigned to your radiance values. Radiance products related to ASTER, MODIS, and many other sensors generally come in units of watts/meter^2/micrometer/steradian. FLAASH requires that radiance input is in microwatts/centimeter^2/micrometer/steradian, which ends up being a factor of 10 smaller (hence the scale factor of 10). A basic rule of thumb for figuring out an appropriate scale factor is to find a value that, when divided into your data, produces new values that do not exceed 20. That is a rough guesstimate, but it's a good place to start.
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