[GRASS-user] Differences for r.composite

GRASS GRASS user
1

Greetings
I have a script that runs automatically r.composite but when i compare my RGB with an RGB (using the same images) bur produced with r.composite outside my script I get the same image but with a different aspect (it doesnt seem to be real color). Do i need to apply a color table to my RGB produced from r.composite?

here goes the Metadata

The one with error

r.info map=2008_RGB_MSC08@Mountain
±---------------------------------------------------------------------------+
| Layer: 2008_RGB_MSC08@Mountain Date: Fri Apr 15 09:39:12 2011 |
| Mapset: Mountain Login of Creator: LL |
| Location: TQ |
| DataBase: D:\data\ |
| Title: ( 2008_RGB_MSC08 ) |

Timestamp: none
Type of Map: raster Number of Categories: 32767
Data Type: CELL
Rows: 4653
Columns: 4519
Total Cells: 21026907
Projection: UTM (zone -24)
N: 9059487.76299512 S: 9040875.76299512 Res: 4
E: 576932.87815394 W: 558856.87815394 Res: 4
Range of data: min = 31 max = 32767
Data Description:
generated by r.composite
Comments:
r.composite red=“2008_bandR_MSC08” green=“2008_bandG_MSC08” blue="20\
08_bandB_MSC08" levels=32 output=“2008_RGB_MSC08”
±---------------------------------------------------------------------------+

The one that is OK (not produced in script)
r.info map=ai@Mountain
±---------------------------------------------------------------------------+
| Layer: ai@Mountain Date: Tue May 17 02:11:55 2011 |
| Mapset: Mountain Login of Creator: LL |
| Location: TQ |
| DataBase: D:\data\ |
| Title: ( ai ) |

Timestamp: none
Type of Map: raster Number of Categories: 32767
Data Type: CELL
Rows: 4653
Columns: 4519
Total Cells: 21026907
Projection: UTM (zone -24)
N: 9059487.76299512 S: 9040875.76299512 Res: 4
E: 576932.87815394 W: 558856.87815394 Res: 4
Range of data: min = 0 max = 32767
Data Description:
generated by r.composite
Comments:

| r.composite red=“2008_bandR_MSC08@Mountain” green=“2008_bandG_MSC08@Mou\ |
| ntain” blue=“2008_bandB_MSC08@Mountain” levels=32 output=“ai” |
| |
±---------------------------------------------------------------------------+

Thanks
Luisa

2

Luisa Peña wrote:

I have a script that runs automatically r.composite but when i compare my
RGB with an RGB (using the same images) bur produced with r.composite
outside my script I get the same image but with a different aspect (it
doesnt seem to be real color). Do i need to apply a color table to my RGB
produced from r.composite?

No; r.composite generates the colour table.

Any map generated by r.composite with a given number of levels should
have the same colour table, regardless of the data.

--
Glynn Clements <glynn@gclements.plus.com>