FORESTRY
REMOTE SENSING
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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(R-NIR)/(R+NIR)
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(NIR-R)/(R+NIR)
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(NIR-R)/(NIR+R)
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(NIR+R)/(NIR-R)
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Detailed explanation-1: -The NDVI quantifies vegetation by measuring the difference between near-infrared (NIR) (which the vegetation strongly reflects) and red light (which the vegetation absorbs/has a low reflectance) (Eq. 26.1).
Detailed explanation-2: -The previous graphs illustrate continuous reflectance spectra, but the NDVI is only focused on two specific regions of the spectrum; the near infrared (NIR) at approximately 800 nanometers is combined with reflectance in the red region, which typically is at approximately 650 to 700 nanometers (Figure 10).
Detailed explanation-3: -NDVI values range from +1.0 to-1.0. Areas of barren rock, sand, or snow usually show very low NDVI values (for example, 0.1 or less). Sparse vegetation such as shrubs and grasslands or senescing crops may result in moderate NDVI values (approximately 0.2 to 0.5).