NORMALIZED DIFFERENCE WATER INDEX (NDWI):

The Normalized Difference Water Index (NDWI) is a new method that has been developed to delineate open water features and enhance their presence in remotely-sensed digital imagery.

And is used to differentiate water from the dry land or rather most suitable for water body mapping. Water has a positive value. The NDWI makes use of reflected near-infrared radiation and visible green light to enhance the presence of such features while eliminating the presence of soil and terrestrial vegetation features.

It is suggested that the NDWI may also provide researchers with turbidity estimations of water bodies using remotely-sensed digital data.

Calculation Of NDWI:

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

DELINEATION BY RECLASSIFICATION OF NDWI:

Reassignment or reclassification operations consist of the total or partial modification of the values of a raster. Reclassification allows you to group together the current values of a raster.

These operations can be useful in the analysis of the different types of rasters, Digital Elevation Models, discrete raster, satellite images.

Here, the NDWI obtained is reclassified into two classes named “water” and “non-water” based on the NDWI values.