Calculating NDWI in Erdas IMAGINE 2014

How is NDWI calculated?

NDWI = (G-NIR)/(G+NIR)



The Normalized Difference Water Index (NDWI) is derived from the Near-Infrared (NIR) and Green (G) channels. This formula highlights the amount of water in water bodies.

How do you calculate NDVI and NDWI?

NDVI = (NIR – Red) / (NIR + Red)



Higher the value of NDVI reflects high Near Infrared (NIR), means dense greenery. Generally, we obtain following result: NDVI = -1 to 0 represent Water bodies. NDVI = -0.1 to 0.1 represent Barren rocks, sand, or snow.
 

How is NDVI calculated in erdas imagine?

NDVI= (NIR-Red) / (NIR + Red)



Pixels with low values close to 0 are bare areas (soils, pavement, etc.)