## NAME

CELL driver - driver to redirect graphical output into a raster map
(drivers)

## DESCRIPTION

The CELL driver can be used to redirect the output of the GRASS monitor into a raster map. Features are:

- storing graphical output into a file with better resolution than through screen grabbing.
- saving 3-dimensional output from d.3d or other display programs to a D_cell raster map.
- saving display overlays (raster/raster/vector/...) to a file for high resolution export with r.out.tiff or similar

The user will find a D_cell raster file in GRASS database after starting the driver and using d.rast, d.vect etc. and finally stopping the driver again. The D_cell raster file is written during closing procedure (this may require some time according to the selected resolution).
Then the user can export this file through r.out.tiff etc. for use in external mapping software.

Be aware that D_cell map is in a xy-projection which may differ to the current location's projection. So the D_cell map cannot be directly displayed on a GRASS monitor.

## Usage in details

- Set the map size for the CELL driver:
    `export GRASS_WIDTH=xxx` (default is 640)
    `export GRASS_HEIGHT=yyy` (default is 480)
    If "export" command is not accepted by your shell, use "setenv" instead:
    `setenv GRASS_WIDTH xxx`
    `setenv GRASS_HEIGHT yyy`
- Start the CELL driver:
    `d.mon start=CELL` Wait for "Ready" message (may take some time due to the file size selected)
    `d.mon select=CELL`
- Now the user can work with the common display modules:
    `d.zzzz (d.rast, d.vect, d.3d,...)` Note that an eventually started GRASS monitor won't display anything as the output is redirected to D_cell file.
- Stop the CELL driver (and write D_cell file):
    `d.mon stop=CELL` Note that this may require some time.
- To export theD_cell file, re-set the region:
    `g.region raster=D_cell`
    Use the r.out.* export module.

## NOTES

Note that the D_cell raster map is in xy-projection with simple xy-coordinates.

The resolution of the D_cell raster map is defined by the map extents. Use g.region -p to get the number of rows and cols and use the environment variables to set the D_cell size.

Note that the CELL driver is limited to 8bit colors.

## SEE ALSO

d.mon, g.region, htmlmapdriver, pngdriver, XDRIVER, tcltkgrass cell-tiff script

## AUTHOR

CERL

Last changed: $Date: 2002/01/25 05:45:32 $