How to compute landsat 8 NDVI in Envi 5.2

Landsat 8 NDVI

I hope that you are doing great and safe from the coronavirus Pandemic.

In this tutorial I will demonstrate how to compute the normalized Difference vegetation Index Using Envi 5.2 software.

NDVI is used to quantify vegetation greenness and is useful in understanding vegetation density and assessing changes in plant health.

IT is calculated as a ratio between the red (R) and near infrared (NIR) values 

(NIR - R) / (NIR + R) ....equation 1

How to How to compute landsat 8 NDVI 

Step 1: Open envi software and load Landsat 8 bands B4 and B5

loading Band 4 and 5 in envi 5.2

Step 2: Convert the two bands each from Digital number values to Top of atmosphere reflectance. For a full tutorial on how to convert DN to TOA, check out this tutorial https://www.atomgeospatial.com/2020/06/how-to-convert-landsat-8-dn-to-top-of.html. 

Step 3:After preprocessing the bands to TOA, Click basic tools--> Band math and type in the equation (B5-B4)/(B5+B4)

NDVI equation in band math

Use the variable to band option to select the TOA band  4 and 5 respectively when prompted by envi software.

Further Choose a location to save the output product and click ok

specify band 4 and 5

Step 4. Visualize your output in a new window. To change the color mapping, on the image window click tools-->color mapping-->envi color tables: and select any combination of colors you prefer.

output landsat 8 NDVI Image