speed of d.rast

[Xin Zhuang]

I have a tract layer (600x400; resolution=30m).
Then I created another layer just part of the tract.
I meant 75% area were "no data" (cat=0).
In order to get the same color scheme, I physically
copied colr.tract to colr.new_layer. However,
the displaying of new_layer took 10 times as much
as d.rast tract. Can any one tell me why this happened?
Is this caused by so many "no data" cells
and thereby a lookup delay?

--Xin
zhuang at access.digex.com