What is this funny CELL driver in GRASS?
The CELL driver exists for file output instead of graphical monitor
output. Use that for:
- storing graphical output into a file with better
resolution than through screen grabbing.
- saving 3-dimensional output from d.3d to a file
- saving overlays (raster/raster/vector/...) to a file
for export with r.out.tiff or similar
You will find a "D_cell" raster file in your GRASS database
after starting the driver, using d.rast, d.vect etc.(find some
hints for d.3d and CELL driver) and
stopping the driver again.
Then you can export this file through r.out.tiff etc. into
your mapping program (xfig or what you like) or may use it
Be aware that "D_cell" is in a different projection than the
usual raster files and can be displayed on a GRASS monitor only
with a trick.
Usage in details:
Set the raster file size for CELL driver
export GRASS_WIDTH=xxx #if you want another size than the default 640
export GRASS_HEIGHT=xxx #if you want another size than the default 480
Example: You want 1000x1000 for a nice poster:
If "export" is not accepted in your shell, try "setenv" instead:
setenv GRASS_WIDTH 1000
setenv GRASS_HEIGHT 1000
d.mon start=CELL # Wait for "Ready" message (may take some time due
to the file size selected)
d.yyyy # use your display command (you will see nothing
(d.rast, d.vect, certainly, because the output is directed into
d.3d,...) the file D_cell)
-> use -o flag for second, third raster overlay!
d.mon stop=CELL # now the D_cell file is written (will also take
time, wait for CPU/Harddisk getting ready)
- If you like: Look at the file
use a trick:
g.region raster=D_cell # this sets the region to
d.mon start=x0 # start after using g.region
d.rast D_cell # should work...
d.mon stop=x0 # stop it (it is in D_cell projection)
g.region -d # don't forget to reset the
d.mon start=x0 # start after using g.region -d
if you want to display usual maps
(Hint: If you already have started a X-monitor, use d.mon select=x0
and d.erase after the g.region commands instead of starting and
stopping the X-Monitors.)
- If you like: Export the file
g.region raster=D_cell # set the region to CELL
r.out.tiff [-p] input=D_cell output=D_cell.tiff
# use -p for 8bit instead of 24bit TIFF export
g.region -d # reset the region to your coordinates
Many thanks to Michel Wurtz - LTE for his hints!
20. Jan. 1999
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