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NDVI USING LANDSAT 9

February 12, 2022

Vewa is an artificial reservoir used to store water for irrigation needs. According to the history, many kings had constructed tanks in Anuradhapura and Pollonnaruwa.

Sri Lanka has a large number of tanks but only the names of a handful of major irrigation tanks, in Anuradhapura and Polonnaruwa districts are included in this image.

The Landsat mission, is a partnership between NASA and the U.S. Geological Survey. Landsat 9, the newest Landsat satellite also has two instruments onboard—the operational land imager and the thermal infrared sensor. The operational land imager can collect data within different visible and infrared wavelength ranges called spectral bands. The spectral bands are useful in deriving the Normalized Difference Vegetation Index (NDVI) images, which can detect patterns of change of vegetation across an area.

The value of the NDVI, which is derived from the red and near-infrared bands typically ranges from -1 up to +1. High positive values are associated with denser, healthy vegetation. Bare soil value is close to zero and negative values indicate water bodies.