[GRASS-user] Help combining raster and vector data into single raster image

[Romy Schneider]

I am currently trying to take a raster map and a vector map and  
combine them to produce a raster (image) map.  I am running GRASS  
6.1.0 on an Intel Mac and have tried several different avenues, none  
to any success.  If anyone has any successful experience with any of  
the following methods, I would greatly appreciate any help you could  
provide.

1.  First tried displaying everything in the "Map Display" window,  
saving this image as a TIFF, JPG, BMP, and/or a PPM, and then  
importing this image using r.in.gdal.
   In every case, the output image looks fine, but r.in.gdal imports  
the three bands (red, green, blue or 1, 2, 3) as empty files.  At  
least, when I display the files, there is nothing there.  I tried  
combining the three bands into a single RGB raster using r.composite,  
and also tried overriding the projection on import in case there was  
a problem with that, but neither trick worked.  Is there something I  
am missing here?

2.  Also tried using the regular display monitor with the PNG driver  
to save a PNG file.  Similar problem, as I can produce the png file,  
but when I import this into Grass, it again is an empty file.     I  
would like to use the CELL driver (per Grass 5 documentation), but  
this feature must have been removed from Grass 6, because it is not  
listed as a valid display monitor with d.mon -l and when I try the  
command "d.mon start=CELL" it says there is no such monitor as 'CELL'.

3.  I also tried to get around the apparent r.in.gdal problem by  
using gdal_translate to translate the various image files (TIFF, JPG,  
etc) into an ArcInfo ASCII grid and then import this into Grass using  
r.in.arc.  While gdal_translate writes the Arcinfo grid sucessfully,  
trying to import this file in grass using r.in.arc results in the  
following error:
r.in.arc: ** errors detected in header section **

   illegal line in header
   dx           1.000000000000
   "cellsize" field missing from header
   "nodata_value" field missing from header
ERROR: Can't get cell header


Does anyone what I am doing wrong in any of these methods (it is very  
likely I am missing something, I've only been using grass for a  
couple of weeks)?  Or have any tips on how to accomplish what I want  
to produce?

Thanks in advance for any advice.

Romy