Karen Kowalewsky
New Member
Posts:9  
| 14 Jun 2022 05:29 AM |
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What is the recommended way to apply the conversion factor (10^-3) to convert J/cm^2 sr um or W*s/cm^2 sr um to uW/cm^2 sr nm? Would I do this is ENVI Classic Basic Tools or in the ENVI GUI Raster Tools or Radiometric correction tools?
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MariM
Veteran Member
Posts:2396 
| 14 Jun 2022 09:01 AM |
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If these gains/offsets are provided in the image metadata (or ENVI .hdr file), then you can use the Radiometric Calibration tool to convert them to 'FLAASH settings' which is uW/cm^2 sr nm. Otherwise, you can manually apply the values to the data using Band Math in either classic or ENVI.
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Karen Kowalewsky
New Member
Posts:9
| 14 Jun 2022 11:19 AM |
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ok, so how does ENVI band math allow me to do for n=1, 421, b=b(n)*125000? I have to multiply each band by 125000 to get from one set of units to the next.
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Karen Kowalewsky
New Member
Posts:9
| 14 Jun 2022 12:58 PM |
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I'm not sure if my reply went through - I don't have gain/offsets at this time. I could go with gain =1, offset =0. I looked at Band Math; I have 421 bands to convert using the single conversion factor. Where/how does band math allow me to do the calculation for all the bands or do I have to have 421 separate expressions: b1*125.0, b2*125.0.....b421*125.0 or will it allow something like for n=1, 421, b(n)*125.0?
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MariM
Veteran Member
Posts:2396
| 15 Jun 2022 06:24 AM |
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After you write your equation in band math and have to map your variables to bands, instead select 'Map variables to input file'.
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Karen Kowalewsky
New Member
Posts:9
| 15 Jun 2022 07:17 AM |
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OOF...Thanks...I was having one of my dyslexic analyst days..didn't even see that option. Thanks for being my second set of eyes/brain.
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