I agree with Paulo about the google search.  Or you may simply refer to the landsat documentation for details (EVI is on page 13).  See below.

http://landsat.usgs.gov/documents/si_product_guide.pdf

I'd suggest you reading the material available for R package RSToolbox. A google seach on EVI + Landsat will provide you with tons of other references.

at http://bleutner.github.io/RStoolbox/rstbx-docu/spectralIndices.html

http://bleutner.github.io/RStoolbox/rstbx-docu/spectralIndices.html

https://github.com/bleutner/RStoolbox

I agree with Paulo about the google search.  Or you may simply refer to the landsat documentation for details (EVI is on page 13).  See below.

http://landsat.usgs.gov/documents/si_product_guide.pdf

# Paulo and Eric... Kindly explain me the RS toolbox usage in ENVI... i never tried that before.

Dear Atiqa,

RSTolbox is an R package, entirely devoted to be used with R software and other API supporting R language.

R is a powerful programming language and software available for free, with endless list of analysis built as code snipets or libraries (packages).

RSToolbox is an example of library for remote sensing analysis. There are others like landsat package.

Hello Paulo

Actually, right now i have Landsat 7 surface reflectance (SR) products along with EVI (GeoTiff). The EVI value ranges upto 0 - 9000 while i recalculated the EVI from the SR bands and clipped to my study area, than the value ranger from -200 to 178, after applying thresholding in ENVI.

I'm not getting why not the value rnages within -1 to 1.

What i'm missing here or making any mistake.

 Apply the scale factor to the SR values before you compute EVI.

You can try 2- band EVI using this formula EVI2=2.5*((NIR-Red)/(NIR+2.4*Red+1)). Map Algebra in ArcGIS can perform this equation. You can also visit this site and read the article 

http://www.sciencedirect.com/science/article/pii/S0034425708001971

@ Cole, by scale factor, what you actually mean? Kindly explain a little bit.

You can also request vegetation indices directly from USGS:

http://landsat.usgs.gov/documents/si_product_guide.pdf

Yeah... I have seen that and downloaded the direct EVI product...

The Landsat 8 bands central wavelength can be found in the attached picture.

Source: https://earth.esa.int/documents/700255/1819745/IDEAS%2B-VEG-OQC-REP-2647+Landsat+8+Cyclic+Report+-+October+2016.pdf/7c3a5de3-6717-4855-87bd-336eab741107

EVI2=2.5*((NIR-Red)/(NIR+2.4*Red+1)