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I'm processing some landsat 8 files. I'm using this scene LC82260982013325LGN00 and I have to apply i.landsat.toar and export the result as a GTiff. However when I use r.out.gdal it takes a very long time (more than 20 minutes per band) and the resulting file is blank and various GB in size, even when I use compression.

I tried it GRASS GIS 6.4.4 and 7 beta 2.

I have Win8 and 8 gb of ram.

What I am doing wrong?

UPDATE:

The region seems to be well set up

g.region -p                                                                     
projection: 1 (UTM)
zone:       19
datum:      wgs84
ellipsoid:  wgs84
north:      -53.95464176
south:      -6163823.95464176
west:       -67.95813741
east:       715222.04186259
nsres:      30
ewres:      30
rows:       205459
cols:       23843
cells:      4898758937

r.info map=TOAR_LC82260982013325LGN00_B1@Luciano                                
 +----------------------------------------------------------------------------+
 | Layer:    TOAR_LC82260982013325LGN00_B1  Date: Fri Jul 25 12:06:01 2014    |
 | Mapset:   Luciano                        Login of Creator: Luciano         |
 | Location: UTMZone19                                                        |
 | DataBase: C:\Users\Luciano\Documents\grassdata                             |
 | Title:     ( TOAR_LC82260982013325LGN00_B1 )                               |
 | Timestamp: none                                                            |
 |----------------------------------------------------------------------------|
 |                                                                            |
 |   Type of Map:  raster               Number of Categories: -0              |
 |   Data Type:    DCELL                                                      |
 |   Data Units:   unitless             Vertical datum: (none)                |
 |   Rows:         8171                                                       |
 |   Columns:      8181                                                       |
 |   Total Cells:  66846951                                                   |
 |        Projection: UTM (zone 19)                                           |
 |            N:   -5918685    S:   -6163815   Res:    30                     |
 |            E:     715215    W:     469785   Res:    30                     |
 |   Range of data:    min = 0  max = 2.70260743795714                        |
 |                                                                            |
 |   Data Description:                                                        |
 |    generated by i.landsat.toar                                             |
 |                                                                            |
 |   Comments:                                                                |
 |     Reflectance of Landsat-8 OLI/TIRS (method dos4)                        |
 |    -----------------------------------------------------------------       |
 |     Acquisition date (and time) ........... 2013-11-21 (0.0000 h)          |
 |     Production date ....................... 2014-02-17                     |
 |                                                                            |
 |     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) .. -0.00000 to +0.00000           |
 |     DN to Radiance (gain and bias) ........ -0.00000 and +0.00000          |
 |     Mean solar irradiance (ESUN) .......... -0.000                         |
 |     Radiance to Reflectance (divide by) ... -0.00000                       |
 |                                                                            |
 |     Dark object (1000 pixels) DN = ........ 8739                           |
 |     Mode in reflectance histogram ......... -0.00000                       |
 |    ------------------------------------------------------------------      |
 |                                                                            |
 |    i.landsat.toar input_prefix="LC82260982013325LGN00_B" output_prefix=\   |
 |    "TOAR_LC82260982013325LGN00_B" metfile="C:\Users\Luciano\Documents\G\   |
 |    IS DataBase\Landsat\Landsat 8\LC82260982013325LGN00\LC82260982013325\   |
 |    LGN00_MTL.txt" method="dos4" percent=0.01 pixel=1000 rayleigh=0.0       |
 |                                                                            |
 +----------------------------------------------------------------------------+
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3
  • 2
    Have you set the correct GRASS region ?
    – gene
    Commented Jul 25, 2014 at 21:09
  • I updated my question. Could it be that the region is too big?
    – Luciano Selzer
    Commented Jul 25, 2014 at 22:04
  • 1
    Yes, the region was too big. I reduced it and now it works fine. Thanks.
    – Luciano Selzer
    Commented Jul 26, 2014 at 1:06

1 Answer 1

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1

Glad you solved - just as pointer for others:

http://grasswiki.osgeo.org/wiki/Computational_region

The easiest way to prepare for complete map export is to run

g.region rast=TOAR_LC82260982013325LGN00_B1 -p

So, set to the raster map name (or use the entry in the respective right mouse button context menu in the GUI to achieve the same).

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