[GRASS-user] calculating NDVI from i.landsat.toar

[Rajat Nayak]

Dear All,
I am trying to calculate NDVI for my study area using landsat 8 products.
I calibrated images using i.landsat.toar. Now I'm a little confused.
If I use -r flag, I get radiance values at the sensor. If -r flag is not
used
I will get reflectance values.
Now the question is which one of the two,
radiance (obtained using -r flag) or surface reflectance (without any flags)
should I use for calculating NDVI.
It will also be great if you can let me know the difference between the two
and how it will influence my NDVI calculations.

Thanking you
Regards
Rajat Nayak
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