envi burn indices

load post fire image

right click on postfire.dat -> new roi

rename to water. threshold -> select NIR band, set min 0, max 830, enable preview

save roi as .xml

file -> save as -> apply inverse water

masked post fire image

tools -> radiometric calibration -> select masked image -> change type to reflectance

reflectance image

load thermal band

toolbox -> radiometric calibration -> select thermal image -> change type to temperature

calibrated thermal image

toolbox -> layer stack -> select reflectance and calibrated thermal. resampling -> cubic

stacked image

toolbox -> spectral index -> select layer stacked image -> burn area index

output normalized burn ration and thermal from spectral index as well

create 2x2 window. drag and drop images in divided windows, link all

white area in burn index indicates burned area

black area in burn ratio and thermal indicate burned area

to calculate difference of burn ratio pre and post fire

toolbox -> band math -> enter expression -> add to list

select post and pre fire burn ratio as variables

delta burn ratio

burn severity vs delta burn ratio 

right click difference burn ratio image -> new raster color slice

add color to indicate severity levels

delta burn ratio with color slices

reference:

https://www.l3harrisgeospatial.com/docs/burnindicestutorial.html