I have calculated NDVI and SAVI for landsat-8 image. But I am getting higher value of NDVI than SAVI Can you tell me reason for this NDVI=0.46 SAVI=0.34 Specific band pixel values are toa b4- 0.130 toa b5- 0.365 L= 0.5 taken
The formula for SAVI is:
SAVI = (NIR - RED) / (NIR + RED + L) * (1 + L)
The formula for NDVI is:
NDVI = (NIR - RED) / (NIR + RED)
From these formulas, it is clear that, depending on the values that you put in, either one can be higher than the other. In this case, you entered
RED = 0.13 &
NIR = 0.365 &
L = 0.5.
This gives us
SAVI = (0.365 - 0.130) / (0.365 + 0.130 + 0.5) * (1 + 0.5) = 0.354 &
NDVI = (0.365 - 0.130) / (0.365 + 0.130) = 0.475.
All in all, it appears that your calculations are correct. Furthermore, your input values also appear sane, which brings us to the end: NDVI can be higher than SAVI.