Geoscience Reference
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Fig. 2. The flowchart of data processing
The vegetation index is linear correlation to vegetation distribution density, the bigger of
NDVI, the better of vegetation cover. The formula for NDVI calculation can be expressed as
follows:
NDVI = (R nir - R red ) /(R nir + R red ) (1)
Where, R nir in the formula is the reflectance of near infrared band and R red the reflectance of
the red band, corresponding to the second band and the first band of MODIS L1B data with
250 m spatial resolution, respectively.
NDVI value
<0.2
0.2-0.4
0.4-0.6
>0.6
The extent of RD
Intensity
Moderate
Mild
Good protected
Table 1. The relationship of NDVI and the extent of RD (adopted from Hu et al., 2004)
There is a relationship between NDVI and the extent of RD (Hu et al., 2004) as shown in
Table 1. From the table, one can see that if NDVI value is below 0.2, it means there is little
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