NDVI Satellite Imaging Explained for Farmers — A Beginner's Guide
Understand what NDVI is, how satellite imaging works for agriculture, and how EcoShade uses Sentinel-2 data to monitor your farm's vegetation health.
What is NDVI?
NDVI (Normalized Difference Vegetation Index) is a number between -1 and +1 that tells you how healthy and dense your vegetation is. It's calculated from satellite images by comparing how plants reflect near-infrared light versus visible red light.
Healthy plants absorb red light for photosynthesis and strongly reflect near-infrared light — giving a high NDVI (0.6–0.9). Stressed or dead vegetation reflects more red and less near-infrared — giving a low NDVI (0.1–0.3).
How EcoShade Uses Satellites
EcoShade integrates data from two satellite constellations:
| Satellite | Resolution | Revisit Time | Best For |
|---|---|---|---|
| Sentinel-2 | 10m | 5 days | Detailed field-level monitoring |
| Landsat 8 | 30m | 16 days | Long-term trend analysis |
We calculate three vegetation indices for every farm:
- 1. NDVI — Overall vegetation health
- 2. EVI (Enhanced Vegetation Index) — Better for dense canopies, corrects for atmospheric conditions
- 3. SAVI (Soil-Adjusted Vegetation Index) — Accurate for sparse vegetation where soil is visible
Reading Your NDVI Map
When you view your farm's satellite data on EcoShade, here's what the colors mean:
- 🟢 Dark green (0.7–0.9): Very healthy, dense vegetation
- 🟡 Yellow-green (0.4–0.6): Moderate health, possible early stress
- 🟠 Orange (0.2–0.4): Significant stress — investigate immediately
- 🔴 Red (< 0.2): Bare soil or dead vegetation
Practical Applications
Detect Stress Before It's Visible NDVI can reveal crop stress 1–2 weeks before symptoms are visible to the naked eye. If a section of your field drops from 0.7 to 0.5 between satellite passes, investigate — it could be an early disease outbreak, irrigation failure, or nutrient deficiency.
Optimize Irrigation Compare NDVI maps with your irrigation zones. Areas with consistently lower NDVI may need irrigation adjustments.
Track Carbon Sequestration Higher NDVI generally correlates with more active photosynthesis and CO₂ absorption. EcoShade uses this data as one input for carbon sequestration estimates.
Getting Started
Add your farm's GPS coordinates in EcoShade and we'll automatically pull the latest Sentinel-2 imagery. No additional setup required — satellite data is available for farms anywhere in the world.