The document discusses the Normalized Difference Vegetation Index (NDVI), which is a measure of vegetation health based on how plants reflect different wavelengths of light. It provides the formula for calculating NDVI using near-infrared and red light reflectance values. NDVI values range from -1 to 1, with higher values indicating denser vegetation. The document also outlines sources of NDVI data, how to create an NDVI map in ArcGIS, applications of NDVI such as monitoring climate change and agriculture, and concludes that NDVI is a useful measure of greenness.

1. NORMALIZED DIFFERENCE VEGETATION INDEX (NDVI)
Presented by-
SOMENATH GOSWAMI
UID NO.- 21143031032, 2nd Semester
Department of Geo-Informatics
Pandit Raghunath Murmu Smriti Mahavidyalaya
Bankura University
Bankura, West Bengal
Date: 18-07-2022

2. 1
Contents
 Introduction
 Formula of NDVI
 Range of NDVI
 Spectral Reflectance Curve
 Sources of NDVI Data
 How to Create NDVI Map in ArcGIS ?
 Output of NDVI Map
 Advantages & Disadvantages of NDVI
 Applications of NDVI
 Conclusion

3. 2
Introduction
 NDVI is an indicator of vegetation health based on how plants reflect
certain ranges of the electromagnetic spectrum.
 The NDVI is a dimensionless index that describes the difference
between visible and near-infrared reflectance of vegetation cover and
can be used to estimate the density of green on an area of land.

4. Formula of NDVI
NDVI = (NIR - Red) / (NIR + Red) [According to Rouse et al. 1974]
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).
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5. Range of NDVI
The NDVI value varies from -1 to +1.
Higher the value of NDVI reflects high Near Infrared (NIR), means dense
greenery. Generally, we obtain following result:
1. NDVI = -1 to 0 representWater bodies
2. NDVI = -0.1 to 0.1 represent Barren rocks, sand, or snow
3. NDVI = 0.1 to 0.5 represent Shrubs and grasslands or senescing crops
4. NDVI = 0.5 to 1.0 represent Dense vegetation or tropical rainforest
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6. Spectral reflectance curve
Spectral reflectance curve shows the relationship between electromagnetic
spectrum (distribution of the continuum of radiant energies plotted either as a
function of wavelength or of frequency) and the associated percent reflectance for
any given material.
 It is plotted in a chart that represent wavelengths in horizontal axis and percent
reflectance in the vertical axis .This curve will visualize the formula of NDVI
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7. Sources of NDVI Data
There are different sources of NDVI data. We can calculate NDVI from Landsat,
Sentinel 2 MSI data and can directly get from the MODIS, NOAA, SPOT satellite
images. For analysis of Normal Difference Vegetation Index (NDVI), Landsat 7 and
Landsat 8 data’s bands, wavelength & their resolution are given below.
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8. How to Create NDVI in ArcGIS ?
At first open the ArcMap software → Click on the ADD DATA option → Then go to
the folder where the data desired → Select the Landsat 8 (band 5,4) data → click the
ADD option → Then go to tha Windows Option → Select the band 5,4 →Check the
Background
Click on the Arc Toolbox →Then click Spatial Analyst Tool →Then click Map Agebra
→ Then double click on the Raster Calculator → A new dialog box will be appeared →
Gave the (float(B5-B4)/float(B5+B4))→Gave the output raster name (NDVI_Cal)→
Click OK button
 Click on the ADD DATA option → Then go to the folder where the data desired →
Select the Bankura_Shapefile data → click the ADD option → Click on the Arc
Toolbox →Then click Spatial Analyst Tool →Then click Extraction→ Then double
click on the Extract by Mask→ A new dialog box will be appeared → Gave the
Input (NDVI_Cal)→Gave the output raster name (NDVI_BK_Mask)→ Click OK
button.
Right click NDVI_BK_Mask → Click Properties → Then click the Symbology → lick
the Classified → Change the Colour As NDVI → Apply → Click OK 7

9. Output of NDVI
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10. Advantages & Disadvantages of NDVI
Advantages :
1. Larger Monitoring range , better adaptability of time and space .
2. NDVI is especially useful for continental- to global-scale vegetation monitoring
because it can compensate for changing illumination conditions, surface slope,
and viewing angle.
Disadvantages:
1. Lower sensibility for high vegetation coverage zone , posteriority
2. Any time there's very low vegetation cover (majority of the scene is soil), NDVI
will be sensitive to that soil.This can confound measurements.
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11. Applications of NDVI
 Climate change
 Agricultural production
 Desertification
 Fire prediction
 Land cover change
Vegetation health ( e.g. , crops , forest canopy )
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12. Conclusion
 NDVI is a useful measure of neighborhood greenness.
 In addition to showing strong correlation with expert ratings, this
measure has practical advantages including availability of data and
ease of application to various boundaries which would aid in
replication and comparability across studies.
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