[GRASS-user] Exporting RGB Composite Images to GeoTIFF

Michele Toma michele.toma at airborne.aero
Wed Jul 20 17:53:03 PDT 2016


Hi everyone (again),

I am having trouble exporting a composite RGB image into a GeoTIFF format that I can open in Global Mapper, Photoshop, or other programs. This is using Landsat 8 imagery. I am able to open the composite image in QGIS, but not in Global Mapper or Photoshop.

Below is a list of steps that I took to get the image. I am unsure of what settings to use when using r.out.gdal to export my image so that it works in other programs. I am using GRASS 7.0.4.


1.       Import Landsat 8 imagery

2.       Convert the DN to reflectance/radiance

a.       i.landsat.toar input=LC81100362016082LGN00_B output=LC81100362016082LGN00_refl metfile=LC81100362016082LGN00_MTL.txt

3.       Perform pansharpening with i.fusion.brovey addon

a.       i.fusion.brovey -l ms1=LC81100362016082LGN00_refl2 at Osaka ms2=LC81100362016082LGN00_refl3 at Osaka ms3=LC81100362016082LGN00_refl4 at Osaka pan=LC81100362016082LGN00_refl8 at Osaka output_prefix=brovey

4.       Apply histogram equalization using r.colors

a.       r.colors -e map=brovey.red at Osaka color=grey

b.      r.colors -e map=brovey.green at Osaka color=gre

c.       r.colors -e map=brovey.blue at Osaka color=grey

5.       Color balance using i.colors.enhance

a.       i.colors.enhance red=brovey.red at Osaka green=brovey.green at Osaka blue=brovey.blue at Osaka

6.       Create composite RGB. I've run the two commands below and both do not produce what I need:

a.       r.out.gdal input=brovey.rgb at Osaka output=brovey.rgb.tif format=GTiff

Another method that I have tried using an example on the r.out.gdal documentation page:

i.group group=brovey_group input=brovey.red,brovey.green,brovey.blue
g.region rast=brovey.blue -p
r.out.gdal in=brovey_group output=brovey_group.tif type=Float64 \
  createopt="PROFILE=GeoTIFF,INTERLEAVE=PIXEL,TFW=YES"

The result is an image with distorted colors when opened in QGIS. Water has turned a reddish brown color.

Below is the info from r.info for the RGB composite and the red brovey band. What other parameters should I be using when running r.out.gdal to create a GeoTIFF to use in other programs?

r.info map=brovey.rgb
 +----------------------------------------------------------------------------+
| Map:      brovey.rgb                     Date: Wed Jul 20 15:09:58 2016    |
| Mapset:   Osaka                          Login of Creator: Michele         |
| Location: utm53n                                                           |
| DataBase: C:\Users\Michele\Documents\grassdata                             |
| Title:     ( brovey.rgb )                                                  |
| Timestamp: none                                                            |
|----------------------------------------------------------------------------|
|                                                                            |
|   Type of Map:  raster               Number of Categories: 0               |
|   Data Type:    CELL                                                       |
|   Rows:         15682                                                      |
|   Columns:      15382                                                      |
|   Total Cells:  241220524                                                  |
|        Projection: UTM (zone 53)                                           |
|            N:    3947115    S:    3711885   Res:    15                     |
|            E:     621915    W:     391185   Res:    15                     |
|   Range of data:    min = 0  max = 32767                                   |
|                                                                            |
|   Data Description:                                                        |
|    generated by r.composite                                                |
|                                                                            |
|   Comments:                                                                |
|    r.composite red="brovey.red at Osaka" green="brovey.green at Osaka" blue="\   |
|    brovey.blue at Osaka" levels=32 output="brovey.rgb"                        |
|                                                                            |
+----------------------------------------------------------------------------+

r.info map=brovey.red
 +----------------------------------------------------------------------------+
| Map:      brovey.red                     Date: Wed Jul 20 11:08:02 2016    |
| Mapset:   Osaka                          Login of Creator: Michele         |
| Location: utm53n                                                           |
| DataBase: C:\Users\Michele\Documents\grassdata                             |
| Title:     ( brovey.red )                                                  |
| Timestamp: none                                                            |
|----------------------------------------------------------------------------|
|                                                                            |
|   Type of Map:  raster               Number of Categories: 0               |
|   Data Type:    DCELL                                                      |
|   Rows:         15682                                                      |
|   Columns:      15382                                                      |
|   Total Cells:  241220524                                                  |
|        Projection: UTM (zone 53)                                           |
|            N:    3947115    S:    3711885   Res:    15                     |
|            E:     621915    W:     391185   Res:    15                     |
|   Range of data:    min = -0.0133126998922819  max = 0.730339144087813     |
|                                                                            |
|   Data Description:                                                        |
|    generated by r.mapcalc                                                  |
|                                                                            |
|   Comments:                                                                |
|    LC81100362016082LGN00_refl4 at Osaka * k                                   |
|    i.fusion.brovey.py "-l" "ms1=LC81100362016082LGN00_refl2 at Osaka" "ms2=LC |
|    81100362016082LGN00_refl3 at Osaka" "ms3=LC81100362016082LGN00_refl4 at Osaka |
|    " "pan=LC81100362016082LGN00_refl8 at Osaka" "output_prefix=brovey"        |
|    i.colors.enhance.py "red=brovey.red at Osaka" "green=brovey.green at Osaka" " |
|    blue=brovey.blue at Osaka"                                                 |
|                                                                            |
+----------------------------------------------------------------------------+

Thank you,

Michele Toma
michele.toma at airborne.aero<mailto:michele.toma at airborne.aero>
www.airborne.aero

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