[GRASSLIST:1215] Combining raster layers with r.mapcalc

[Bill Dickinson Jr]

Hey there:

In running through the SEEDS tutorial, one of the tasks is combining 
two raster layers into a single raster using r.mapcalc. The 
individual layers show the data properly, but the resulting combined 
layer contains no data. Here is what I do:

Mapset <wbdickinson> in Location <leics2>
GRASS 5.0.2 > r.mapcalc
Enter expressions, "end" when done.
mapcalc> buffers = mwaybuf + railbuf
mapcalc> end

  100%

Mapset <wbdickinson> in Location <leics2>
GRASS 5.0.2 > d.rast buffers
  100%

Mapset <wbdickinson> in Location <leics2>
GRASS 5.0.2 > r.report buffers
r.stats:  100%
+-----------------------------------------------------------------------------
|                         RASTER MAP CATEGORY REPORT                         
|LOCATION: leics2                                     Fri Sep 12 13:30:07 2003
|-----------------------------------------------------------------------------
|          north: 322000    east: 456000                                     
|REGION    south: 310000    west: 444000                                     
|          res:       50    res:      50                                     
|-----------------------------------------------------------------------------
|MASK:none                                                                   
|-----------------------------------------------------------------------------
|MAP: (untitled) (buffers in wbdickinson)                                    
|-----------------------------------------------------------------------------
|                            Category Information                            
|#|description                                                               
|-----------------------------------------------------------------------------
|*|no data                                                                   
+-----------------------------------------------------------------------------

Any thoughts would be appreciated. TIA
   Bill

-- 

Bill Dickinson
GIS Specialist
NASA Goddard Space Flight Center
Environmental & Safety Branch, Code 250
wdickins at pop700.gsfc.nasa.gov