The document defines and explains the Normalized Difference Vegetation Index (NDVI). It discusses how NDVI is calculated using near-infrared and red light reflectance values. NDVI values range from -1 to 1, with higher positive values indicating more dense, healthy vegetation. The document also outlines several applications of NDVI in fields like agriculture, forestry, and drought monitoring.

1. Normalized Difference
Vegetation Index
By
Qazi Muhammad Ehzaz Ul Mohiz
19-GIS-20

2. Contents
 What is NDVI?
 How do you Calculate NDVI?
 Applications
 How To Interpret NDVI Images?
 NDVI Specifications

3. NDVI
 NDVI stands for Normalized Difference Vegetation Index.
 NDVI was introduced by Tarpley and Kogan in 1980’s with the NOAA(National
Oceanic and Atmospheric Administration) in United States.
 There are round about 26 to 28 vegetation indices, like Image Rationing and
Image Differencing , among which NDVI is most popular and accurate vegetation
been used.
 This vegetation index is used to study the properties of different vegetation.
 NDVI quantifies vegetation by measuring the difference between near-infrared
(which vegetation strongly reflects) and red light (which vegetation absorbs)
 It focuses on health of vegetation and separate healthy vegetation from other
features.

4. How do you calculate NDVI?
 As shown below, Normalized Difference Vegetation Index (NDVI) uses the
NIR and red channels in its formula.
(NIR - R) / (NIR + R)
In Landsat 4-7, NDVI = (Band 4 – Band 3) / (Band 4 + Band 3).
In Landsat 8-9, NDVI = (Band 5 – Band 4) / (Band 5 + Band 4).
• It is calculated in Raster Calculator tool of ESRI Arc GIS.
• Healthy vegetation(chlorophyll) reflects more near-infrared (NIR)
and green light compared to other wavelengths, But it absorbs
more red and blue light.
• This is why our eyes see vegetation as the color green, If you
could see near-infrared, then it would be strong for vegetation
too.
• Satellite sensors like Landsat and Sentinel-2 both have the
necessary bands with NIR and red.

5. Normalized Difference Vegetation Index
 NDVI always scientific ranges from -1 to +1.
• When you have values less than zero , it represent all other features rather
than vegetation.
• When you have values more than zero, it represent all kind of vegetation.
• When you have values close to zero, there are likely no green leaves and it
could even be an urbanized area.
1. Dead Plants-------------------- -1-0
2. Unhealthy Plants-------------- 0-0.33
3. Moderate Healthy Plants----- 0.33-0.66
4. Very Healthy Plants----------- 0.66-1

8. Applications
 We see several sectors using NDVI. For example, in agriculture, farmers use
NDVI for precision farming and to measure biomass.
 Whereas, in forestry, foresters use NDVI to quantify forest supply and leaf
area index.
 Furthermore, NASA states that ”NDVI is a good indicator of drought” When
water limits vegetation growth, it has a lower relative NDVI and density of
vegetation.
 It is used for identifying and monitoring droughts affecting agriculture.
 In reality, there are various of applications where NDVI are being applied in
the real world.

9. How To Interpret NDVI Images?
 Traditionally, NDVI results are presented as a color map, where each color
corresponds to a certain range of values. There’s no standard color palette, but
most software uses the “red-green” one, meaning that red-orange-yellow tints
indicate bare soil or dead/sparse vegetation, and all shades of green are a sign of
normal to dense vegetation cover.
EOSDA Land Viewer

11. By USGS

12. Thank You…