| 18 Oct 2011 04:29 PM |
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Hi All,
I calculated the Enhanced vegetation Index (EVI) with Band math on SPOT VGT s10 but have a strange result.
>> The values under by cursors on the EVI band image shows values like -40, 0.1,...
(Range of EVI is -1 to +1), the min/max plot statistics show values from -40 to 146...?
I computed it by;
2.5 *( (float(B4)-B3)/(B4+6*float(B3) - 7.5 *float(B1)+1) )
Thank you
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MariM
Veteran Member
Posts:2396  
| 20 Oct 2011 07:18 AM |
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The equation worked for me with some Landsat data converted to reflectance. Did you convert your SPOT data to reflectance?
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Deleted User
New Member
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| 22 Feb 2012 05:08 PM |
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Hi I'm new to using ENVI and I would like to produce a vegetation index. I have SPOT imagery but am time poor so I dont want to carry out a supervised classification. I have produced an NDVI but I would like to make an EVI to compare it to. Can anyone tell me how to go about it?
Many Thanks
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Deleted User
New Member
Posts:
| 22 Feb 2012 05:08 PM |
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Hi I'm new to using ENVI and I would like to produce a vegetation index. I have SPOT imagery but am time poor so I dont want to carry out a supervised classification. I have produced an NDVI but I would like to make an EVI to compare it to. Can anyone tell me how to go about it?
Many Thanks
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Deleted User
New Member
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| 06 Feb 2016 04:41 AM |
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I tried this same expression for Landsat7 SR data, but band math is giving sytax error
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Deleted User
New Member
Posts:
| 07 Feb 2016 09:24 PM |
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Perform the equation using "b1" as variable instead "B1" as:
2.5 *( (float(b4)-float(b3))/(float(b4)+(6*float(b3)) - (7.5 *float(b1))+1) )
It should work now.
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