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

[Jiao Wang]

Hi Rajat,

Surface reflectance should be used for calculating NDVI.
Here is a link that explains the difference between radiance and surface
reflectance.

Best,
Jiao


On Tue, Jul 1, 2014 at 11:59 PM, Rajat Nayak <rajat27404 at gmail.com> wrote:

> 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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