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