Vegetation Index Interpreter

What it does

When you photograph a canopy with a multispectral or hyperspectral camera, software boils the image down to a few single "vegetation index" numbers — NDVI, PRI, and reflectance in specific colour bands. NDVI (Normalized Difference Vegetation Index) measures how green and dense a canopy is; PRI (Photochemical Reflectance Index) tracks how efficiently the plant is using light and whether it is stressed. This tool takes those already-computed numbers and translates them into plain plant-status estimates. Note the name: it does NOT read a raw hyperspectral image — you type in index values from your own sensor.

When to use it

When you already run a drone, camera, or field sensor that outputs NDVI/PRI and you want a quick read on canopy health. It works for any leafy crop with a measurable canopy. If you do not have a spectral sensor producing these indices, this tool is not for you — there is nothing to enter.

How it calculates

• Inputs are scalar vegetation indices you enter, not a hyperspectral spectrum. NDVI tracks canopy greenness/chlorophyll and PRI tracks light-use/stress, but the index-to-status coefficients here are heuristic and not calibrated.

What you enter

NDVI Reading

Normalized Difference Vegetation Index from a multispectral sensor or drone: (NIR − Red) / (NIR + Red). Healthy dense canopy ≈ 0.7–0.9.

PRI Reading

Photochemical Reflectance Index (reflectance at 531nm vs 570nm) from a spectral sensor; tracks light-use efficiency and stress. Typically −0.1 to +0.1.

Green Reflectance (550nm)(%)

Percent of 550nm (green) light the canopy reflects, from a spectrometer or calibrated camera.

Red Edge (720nm)(%)

Percent reflectance at 720nm (the red-edge band), from a spectral sensor; sensitive to chlorophyll and nitrogen.

What you get

Chlorophyll Content Index

Plant Stress Level(%)

Nitrogen Status Score(/10)

Water Stress Indicator(%)

Reading the result

Higher NDVI (0.7–0.9) means a healthy dense canopy and pushes the Chlorophyll and Nitrogen scores up while pulling Stress down; low NDVI with negative PRI drives Stress and Water Stress high. A Nitrogen Status Score near the top of /10 suggests adequate N; a low one is a prompt to check feed. Because the index-to-status math here is heuristic (uncalibrated), use these as flags to go scout the plants, not as measured lab values — a low score means "go look," not "add exactly X."

Related calculators

• Plant Stress Snapshot
• Photosynthetic Rate Calculator
• Light Recipes
• Light Requirements Calculator