ENVI Software Claculating Normalized Difference Built Index NDBI

Normalized Difference Built-up Index (NDBI) is used to extract built-up features and have indices range from -1 to 1.

     
 Normalized Difference Built-up Index NDBI = (SWIR – NIR)/(SWIR + NIR)

in Band Math tool, use the Expression:

NDBI=(float(B6)-float(B5))/(float(B6)-float(B5))

* Define the variables to bands pairings.