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

[Vishal Mehta]

rajat,

i am doing something similar: Landsat 8 for landcover classification.

although not an answer to your specific qn, here are a couple of other
links i found useful for GRASS/landsat workflow:

http://landsat.usgs.gov/L8_band_combos.php

http://courses.neteler.org/processing-landsat8-data-in-grass-gis-7/

Best,
Vishal





On Wed, Jul 2, 2014 at 12:16 PM, Jiao Wang <jiao at hawaii.edu> wrote:

> Forgot the link:
>
> http://www.exelisvis.com/Home/NewsUpdates/TabId/170/ArtMID/735/ArticleID/13592/Digital-Number-Radiance-and-Reflectance.aspx
>
>
>
> On Wed, Jul 2, 2014 at 8:59 AM, Jiao Wang <jiao at hawaii.edu> wrote:
>
>> 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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>>> grass-user mailing list
>>> grass-user at lists.osgeo.org
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>>>
>>
>>
>
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-- 
Vishal K. Mehta, PhD
Scientist
Stockholm Environment Institute - US
133 D St Suite F
Davis CA 95616
www.sei-us.org
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