Guides
Remote-Sensing Indices in 5 Minutes: NDVI, NBR & NDWI Basics
May 5, 2025
Monitoring Indices in 5 Minutes: NDVI, NBR & NDWI Explained
TL;DR — Vegetation loves NDVI, fire scars show up in NBR, and water issues surface via NDWI. Choose the right one and you can enhance days of fieldwork with a few cloud‑free scenes.
Why Indices Matter in 2025
Spectral indices turn raw reflectance into single‑band metrics a manager can read at a glance. Yet close to 80 % of global vegetation monitoring still relies on one index—often the wrong one for the question. Orbica’s monitoring projects start by matching each decision to the index that actually describes it.
Basic Indices in Plain English
Hundreds of indices exist—SAVI, MNDWI, NBRSWIR, MIRBI and more. This article is a quick start! not a PhD thesis. The colour‑coded rules that follow (green → NDVI, burn → NBR, blue → NDWI) address a good portion of field questions. When they don’t, Orbica offers alternative indices in a click. Treat these as starting forks, not hard limits
Index | Reveals | Quick formula* |
|---|---|---|
NDVI (Normalised Difference Vegetation Index) | Leaf‑level “greenness”, stress & growth | (NIR − Red) ⁄ (NIR + Red) |
NBR (Normalised Burn Ratio) | Burn extent & severity after wildfire | (NIR − SWIR2) ⁄ (NIR + SWIR2) |
NDWI (Normalised Difference Water Index) | Water bodies, shoreline change, some turbidity | (Green − NIR) ⁄ (Green + NIR) |
*Band numbers vary by sensor—see NASA and USGS band tables for specifics.
Rule of thumb:
Green? Use NDVI.
Burn? Use NBR.
Blue? Use NDWI.
Which One, When?
Your business question | Best index | Good free sensor |
|---|---|---|
“Is my pine canopy bouncing back after thinning?” | NDVI | Sentinel‑2 (10 m) |
“How severe was last week’s fire?” | dNBR (pre‑ vs post‑fire) | Sentinel‑2 (10 m) |
“Where is sediment clouding the reservoir outlet?” | NDWI | Sentinel‑2 (10 m) |
Want to see these numbers on your own block, farm or catchment? Book a demo and we’ll run a sample scene for free.
Real‑World Win: Bridge Hill Burn Severity
In 2024 a wildfire swept hundreds of hectares of forest near Bridge Hill. Orbica can process Sentinel‑2 imagery on weekly intervals after containment; the NBRSWIR map flagged over 400 ha of high‑severity burn. Forestry crews could have accelerated on‑foot plots, which cost thousands of dollars and weeks of labour. Fast data, actionable intel.
Three Pro Tips for Effective Land Monitoring
Mask clouds first – Even 5 % cloud can shift NDVI significantly, impacting accuracy. Apply cloud masking before calculating.
Set alerts instead of babysitting dashboards - Let your tool ping you the moment an index crosses a risk threshold.
Sanity check with true colour - Overlay a true colour image if you need to get your bearings.
Orbica bakes automatic cloud masking, real‑time threshold alerts, and a one‑click true‑colour overlay into every workflow—so you get decision‑ready maps without losing sight of the science behind each pixel.
Why Orbica?
Remote‑sensing workflows are littered with manual steps—scene hunting, cloud masking, band maths, threshold tuning, exporting, re‑projecting. Orbica automates the lot.
Scene selection – Our pipeline automatically grabs the most recent, clearest images for your Area of Interest.
Smart cloud masking – Ever said "that could be cloud though"? Clouds are stripped out automatically so you know you're only looking at land.
Index engine – NDVI, NBR, NDWI, and over 100 other indices can be applied to your area of interest to maximise the information you get out of your land
Delivery to your inbox – Decision‑ready reports and GIS layers land in your inbox—no scripts, no headaches.
👉 Book a free 15‑minute demo and watch automatic land insights unfold live over an area you choose.