The objective of this lab is to use spectral indices to identify burned areas. The aim of this assignment is the generation of a burn severity map for the assessment of the areas affected by wildfires. The Normalized Burn Ratio (NBR) is used, as it was designed to highlight burned areas and estimate burn severity. It uses near-infrared (NIR) and shortwave-infrared (SWIR) wavelengths. Healthy vegetation before the fire has very high NIR reflectance and a low SWIR response. In contrast, recently burned areas have a low reflectance in the NIR and high reflectance in the SWIR band. More information about the NBR can be found here. The NBR is calculated for images before the fire (pre-fire NBR) and for images after the fire (post-fire NBR) and the post-fire image is subtracted from the pre-fire image to create the differenced (or delta) NBR (dNBR) image. dNBR can be used for burn severity assessment, as areas with higher dNBR values indicate more severe damage whereas areas with negative dNBR values might show increased vegetation productivity. dNBR can be classified according to burn severity ranges proposed by the United States Geological Survey (USGS).

By the end of this assignment you should be able to generate the Normalized Burn Ratio and the difference between pre-fire and post-fire images. You should also be able to generate legends for the maps and calculate the areas burned.

Acknowledgement: This lab is partially based on the step-by-step tutorial of the UN - SPIDER Knowledge Portal.