This article reviews prominent water detection indices - NDWI, MNDWI, NDMI, AWEI, and WRI - highlighting their distinct formulas, applications, and limitations in remote sensing analysis.
NDWI
Normalized Difference Water Index
Developed by McFeeters (1996) to identify open water bodies using spectral reflectance differences:
Formula:
NDWI = (NIR - Green) / (NIR + Green)
Principle:
- High reflectance in Green band
- Strong absorption in Near-Infrared (NIR) band
- Maximizes contrast between water and vegetation/soil