| 24 Jan 2013 09:58 PM |
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Hi everyone
I would like to know the correct expression of GRVI in band math. I tried to write the many expression, but the result was not realistic. I think the problem in writing is Prioritization of algebraic operations. How can i write the correct expression. I will be glad to help me.
Thank you
Hadi
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Deleted User
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| 25 Jan 2013 08:36 AM |
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I'm not familiar with GRVI, but in the IDL help, you can find a section that explains the precedence of mathematical operators. You will want to look under IDL Programming > Concepts > Operators > Operator Precedence. Or just search on Operator Precedence.
- Peg
Exelis VIS
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Deleted User
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| 25 Jan 2013 08:38 AM |
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What is GRVI? It sounds like some kind of a vegetation index.What is the definition?
You should also let us know what expressions you used so we can see why they might be wrong.
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Deleted User
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| 27 Jan 2013 06:11 PM |
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Dear
GRVI is a vegetation index with this equetion (GRVI= B2-B3/B2+B3).
Best regards, Hadi
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MariM
Veteran Member
Posts:2396 
| 28 Jan 2013 05:38 AM |
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That is essentially the equation you would use:
(b2-b3)/(b2+b3)
If your data is not already in a floating point data type, you will need to 'float' these variables:
(float(b2)-float(b3)) / (float(b2)+float(b3))
Your might also want to calibrate your data to reflectance.
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Deleted User
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| 28 Jan 2013 06:02 AM |
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Dear
Thank you so much for your nice help.
Best regards, Hadi
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