can not allocate any read/write color cells

Rick Gagne rghydro at
Tue Apr 11 22:51:49 EDT 2000

On Tue, 11 Apr 2000 18:22:06 -0400, Horacio wrote:

>I just upgraded my video card + monitor but can't get to display any
>graphic in grass...
>I get the following error:
>GRASS: > d.mon start=x0
>can not allocate any read/write color cells
>I'm sure that it is a very simple thing about the card setting or
>somthing... can somebody tell me what i should do to get the display
>I'll appreciate any help.... and will sum.

Hi Horacio,

Your problem is likely caused by not having set the color depth correctly 
when you configured the  Xserver  for your new card and monitor.

To see what color depth your system is in, while in  X-display mode, type 
xdpyinfo. If it returns 8 bit depth, then video-ram permitting, increase the 
color depth to 16, 24 or 32 bits. I do this (plus I adjust for changing screen 
resolutions on-the-fly with cntr-alt-+) by hacking inside the Xconfiguration file 
(but be careful in there!).

In 1998, Markus Neteler suggested the following:

1.  Create the file .xserverrc (with a text editor) if it does not already exist in 
your home directory.

2.  At the end of the file, you should see (or create) something like this:

	exec X  :0 -auth .Xauthority -bpp 32 $*


	exec X :0 -bpp 32 $*

	where -bpp 32 (or -bpp 24 or -bpp 16 for ram deprived machines)
	establishes the color depth used the next time Xserver starts.

Best of luck,



RG Hydro-Environmental Ltd.
WaterWatch ..... independent groundwater research

Richard Gagne, P.Geo., President
PO Box 25099
Halifax, NS  Canada   B3M 4H4

e-mail: rghydro at
phone: (902) 457-7010
fax: (902) 457-3934

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