NDWI (Normalized Difference Water Index)

Normalized Difference Water Index (NDWI) is a way of measuring the presence and changes of water on the Earth’s surface. It is calculated by comparing the amount of green light (which water reflects strongly) and near-infrared light (which water absorbs) that is reflected by the land cover. NDWI values range from -1 to +1, where higher values indicate more water and lower values indicate less or no water.

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