Spectral Indices

NDVI vs NDWI vs NBR: which index should you use?

BGPD Labs · Spatial Intelligence Lab

Spectral indices help transform raw satellite bands into interpretable signals. The challenge is choosing the right index for the right question.

NDVI: vegetation greenness

NDVI is commonly used to highlight vegetation vigor and greenness. It is useful for agriculture, land cover review, vegetation monitoring and early screening of crop stress.

NDWI: water detection

NDWI is commonly used to highlight open water and moisture-related patterns. It can help identify reservoirs, flood extent, wetland changes and surface water boundaries.

NBR: burn severity and disturbance

NBR is commonly used in fire impact analysis because burned areas often change strongly in near-infrared and shortwave-infrared bands.

Practical rule

• Use NDVI when the question is about vegetation condition.
• Use NDWI when the question is about water presence or extent.
• Use NBR when the question is about burned areas or severe land disturbance.

The real bottleneck

The index is only the first step. Decision makers usually need area statistics, confidence, comparison dates and a clear explanation of what the change means.