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I am trying to calculate EVI values from Sentinel-2 Level 1C. When I calculate the EVI with this formula : (2.5 * ("Band 8" - "Band 4")) / ("Band 8" + (2.4 * "Band 4") + 1) I got values between -79.6462 to 22.6748. I used to know that EVI ranges between -1 to +1.

I tried this answer to Calculating 2-bands EVI from Sentinel-2, but I still have problems.

When I changed the formula as (2.5 * float("Band 8"/10000 - "Band 4"/10000)) / ("Band 8"/10000 + (2.4 * "Band 4"/10000) + 10000) my values are between -0.000169 to 0.0003. These are close but not expected values too.

Now I want to know if my procedure is okay and what the correct use of the formula for Level 1C is?

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    Correct formula is as follows: 2.5 * float("Band 8"/10000 - "Band 4"/10000)) / ("Band 8"/10000 + (2.4 * "Band 4"/10000) + 1)
    – xunilk
    Aug 8 at 20:20
  • What software are you using to do that?
    – Parsa
    Aug 8 at 21:14
  • I am using python, in script I try this : evi = 2.5*(nir.astype(float)-red.astype(float))/((nir.astype(float)+(6.0*red.astype(float))+(-7.5*blue.astype(float))+1.0)) and the result is between -79.6462 to 22.6748. I divided all band values with 10000 before this line. Is it related with python? parentheses or something? Aug 8 at 23:18
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Just as xunilk said, you shoud replace that last 10000 with 1. The correct formula is: EVI = 2.5 * ("Band 8"/10000 - "Band 4"/10000) / ("Band 8"/10000 + 2.4*"Band 4"/10000 + 1)

I just tested it with a sentinel image and the results was between -0.6 and 1.5 which seems to be acceptable.

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  • At first I divided all bands with 10000, when I said that **2.5 * ("Band 8" - "Band 4")) / ("Band 8" + (2.4 * "Band 4") + 1) I got values between -79.6462 to 22.6748. ** The result is not expected. Aug 8 at 23:21
  • which image did you use for this? which level image? @Parsa Aug 8 at 23:23
  • I don't remember the image level. But my image values were between 1 and 28000. What is range of your original image values?
    – Parsa
    Aug 9 at 10:29
  • It depends on bands, in B02 band : 646 to 3172 in B04 band : 289 to 4103 in B08 band : 181 to 5575 Aug 9 at 11:07
  • I just realized that you didn't use the blue band in calculations. I remember that your formula is for evi2 calculation. Aug 9 at 11:18

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