How to Calculate Normalized Difference Water Index (NDWI) using Erdas Imagine Spatial Modeler #NDWI

Some literature considers NDII as NDWI, the name of this video has been updated later after the video had several viewers.

Normalized Difference Infrared Index (NDII) is a moisture-related index of satellite-derived index that makes use of Near Infrared and Short-Wave Infrared (SWIR) bands to detect changes in water content and spongy mesophyll in vegetation canopies.

Mainly because of its sensitivity to vegetation aridity and drooping, it’s sometimes considered a better indicator of drought conditions than the Normalized Difference Vegetation Index (NDVI), the most widely used remote sensing-based vegetation index.

Its formula is
ρ0.85 − ρ1.65/ρ0.85 + ρ1.65 having similar regions of NIR and SWIR.