v.to.rast

[Clifton Wood]

-- Anthony Burns wrote:
> 
> v.to.rast will only convert vector polygons that are attributed.  All the
> white area indicates those area were not attributed or are open areas.  It
> is best to display your  vector file and then zoom in very very close to
> the actual polygons.  If your doing the files by quads for example that
> will be patched together later then you will need to use the region set by
> you vector file.  This reduces the size of the raster file, or the large
> white area around the outside.  Since you have fields it is possible you
> have large open areas (not polgons) and these will show up white.  Do you
> really need the accuracy of res=1 (1 meter resolution)  If it is a very
> large vector file, such as a full county you might go to a 5 or 10 meter
> resolution if you can accept the loss of accuracy.

OK, that makes sense. But I can go in to v.digit and see that 902
attributes
are there. I'm wondering now if its more a case of unclosed polygons
(yes, 
it is a county layer from NRCS, I think). I'm wondering if v.support
could be used to close all polygons within a certain tolerance. (Was it
"snap"ing that I read about in the user's manual??)

I'll have to take a look at the manual when I get in the office
tomorrow, but does that sound like a good direction to move in? I can't 
imagine having to search a 7km x 7km vector file for polygonal closures! 

%-|

Thanks for the help, Anthony!
============================================================
Clifton B. Wood
Programmer/Analyst for Virginia Tech's AGNIS Department
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