WorldView 2 GEMI
Global Environmental Monitoring Index for WorldView 2
Vegetation Satellite Provider: MAXAR
Applications
global vegetation monitoring
atmospheric effect mitigation
vegetation cover assessment
biomass estimation
environmental monitoring
satellite-based vegetation analysis
Quick Stats
Category: vegetation
Sensor: WorldView 2
Provider: MAXAR
Bands Used: 2
Description
The Global Environmental Monitoring Index (GEMI) is a non-linear vegetation index developed by Pinty and Verstraete (1992) specifically designed to reduce atmospheric effects without requiring detailed atmospheric correction. Unlike NDVI, GEMI maintains information about vegetation cover while being more resistant to atmospheric perturbations.
Formulas
General Formula
WorldView 2 Specific Formula
eta * (1 - 0.25 * eta) - ((Red - 0.125) / (1 - Red)) where eta = (2 * (NIR1^2 - Red^2) + 1.5 * NIR1 + 0.5 * Red) / (NIR1 + Red + 0.5)Spectral Band Visualization
Band Wavelengths
RED: 640-760
NIR: 780-1400
Code Examples
gemi2.py
References
Pinty, B. and Verstraete, M.M. (1992) - GEMI: A non-linear index to monitor global vegetation from satellites. Vegetatio, 101, 15-20