[GRASS-user] i.landsat.toar module on GRASS GIS v7.0.svn

[Hasan Sarptaş]

Hi,

I'm newbie in GRASS GIS and image processing. I want to produce NDVI maps
from Landsat 8 imagery. I try to convert Landsat 8 DN to ToAR by using
i.landsat.toar module in GRASS GIS v7.0.svn - on Windows 8 x64 platform.

The conversion parameters (Earth-Sun distance, sun elevation, DN range,
gain and bias and etc.) are all reported as 0 (zero) in metadata of
resulting ToAR maps (I've added one of the metadata generated by r.info at
the end of my message).

Another issue during the conversion process, i.landsat.toar module warn
that

ESUN evaluated from REFLECTANCE_MAXIMUM_BAND
>
> ???


r.report stats:

n: 10403
> minimum: 0.0227376
> maximum: 0.587083


Is there a problem in 'DN to ToAR conversion' in GRASS GIS 7.0?
How to resolve this issue? And my last question is: Can I trust these
results obtained by i.landsat.toar?

Best regards,
------------------------------
Dr. Hasan Sarptaş

Ege University
Solar Energy Institute
Energy Tech.
İzmir, TURKEY.
me:           http://about.me/sarptas



(Wed Jan 22 02:49:22 2014)

r.info map=ToA_Ref_4 at Landsat

 +----------------------------------------------------------------------------+
 | Layer:    ToA_Ref_4 at Landsat              Date: Wed Jan 22 02:41:47 2014
   |
 | Mapset:   Landsat                        Login of Creator: Hasan
  |
 | Location: Ege
   |
 | DataBase: C:\Users\Hasan\Documents\GIS DataBase\Landsat8
  |
 | Title:     ( ToA_Ref_4 )
  |
 | Timestamp: none
   |
 |----------------------------------------------------------------------------|
 |
   |
 |   Type of Map:  raster               Number of Categories: -0
   |
 |   Data Type:    DCELL
   |
 |   Data Units:   unitless             Vertical datum: (none)
   |
 |   Rows:         7811
  |
 |   Columns:      7671
  |
 |   Total Cells:  59918181
  |
 |        Projection: UTM (zone 0)
   |
  |            N:    4423515    S:    4189185   Res:    30
    |
 |            E:     716115    W:     485985   Res:    30
  |
 |   Range of data:    min = 0.0154847031183999  max = 2.65962954976276
  |
 |
   |
 |   Data Description:
   |
 |    generated by i.landsat.toar
  |
 |
   |
 |   Comments:
   |
 |     Reflectance of Landsat-8 OLI/TIRS (method uncorrected)
  |
 |    -----------------------------------------------------------------
  |
 |     Acquisition date (and time) ........... 2013-12-05 (-0.0000 h)
  |
 |     Production date ....................... 2013-12-05
  |
 |
   |
 |     Earth-sun distance (d) ................ -0.0000000
  |
 |     Sun elevation (and azimuth) ........... -0.00000 (0.00000)
  |
  |     Digital number (DN) range ............. 0 to 0
    |
 |     Calibration constants (Lmin to Lmax) ..
-24740000909121687407621537690 |
 |     DN to Radiance (gain and bias) ........ +0.00000 and +0.00000
   |
  |     Mean solar irradiance (ESUN) .......... 0.000
   |
 |     Radiance to Reflectance (divide by) ... +0.00000
  |
 |    ------------------------------------------------------------------
   |
 |
   |
 |    i.landsat.toar input_prefix="LC81800332013339LGN00_B" output_prefix=\
  |
 |    "ToA_Ref_LC81800332013339LGN00_B" metfile="LC81800332013339LGN00_MTL.txt"
sensor="oli8" met\   |
 |    hod="uncorrected" percent=0.01 pixel=1000 rayleigh=0.0
   |
 |
   |
 +----------------------------------------------------------------------------+
(Wed Jan 22 02:49:23 2014) Command finished (0 sec)
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