d.rast VERRRRY SLOWWWW ????

[Chris Rewerts]

SROSE at flemingc.on.ca (Steven Rose) wrote:
>Hi!  I'm running grass4.1 on DecStation 5000, Ultrix 4.3 with 24 meg 
>RAM.  I have three maps, each covering a 110km x 140km area, with a 
>cell resolution of 10m.  Each map only has one strip of 10km n/s by 
>the width of the map.  Each strip is geographically seperate.  The 
>three cell/ files are 1, 1.4 and 1.8 megs.  When I use d.rast to 
>display these maps seperately, or overtop of each other (the -o 
>option) everything displays fine in a few seconds; HOWEVER, after 
>running r.patch to stick the three maps together, the resulting map 
>(about 4.2 megs) takes about 45 MINUTES to d.rast!!! 
>
>Anybody have any idea what's up?  Did I just overshoot memory 
>requirements or something?  The disk drive does not seem to pounding 
>away like it's swapping like crazy.  I've even shutdown the system 
>and powered back up, but same results.  
>Professor Steven Rose, R.P.F.       Phone: (705) 324-9144
>Sir Sandford Fleming College        FAX:   (705) 878-9312
>PO Box 8000, Lindsay,               Internet: srose at flemingc.on.ca
>Ontario, CANADA K9V 5E6
>


Here is something that works for me in cases of slow d.rast action:
slip in a color rule for what color category 0 (zero) should be (eg
use the r.colors command). It is a long story to describe what is going
on here, but it is a quirk that will be gone with the next grass 
release.

Chris (rewerts at diego.cecer.army.mil) USACERL, Champaign, IL