v.to.rast on small areas

[Ron Owens]

Hi Carla,
You might try the following:

Make a copy of your vector file and in v.digit remove all areas except the 
14 small areas.
Set your region to include only the 14 areas and your resolution very
high (enough to insure the areas will "rasterize").
Run v.to.rast on the new vector file.
Run patch the origional map and the 14 area raster map using r.patch. 
  Remember that r.patch takes most of it's information from the first
  map in the list so depending on which contains the information you
  most desire use that map first.
If you keep the resolution of your origional maplayer there is no way I
know of to insure that the 14 areas will be represented in the patched
map as the resampling may kick them out anyway. Or may kick out some of
them.
Can you tell me what the origional map scale is and at what resolution
you are converting them to raster?

rono


> From: grayling!celenz at uxc.cso.uiuc.edu (Carla Elenz)
> Sender: grass-lists-owner at moon.cecer.army.mil
> Reply-To: grassu-list at moon.cecer.army.mil
> To: cerl!amber.cecer.army.mil!moon.cecer.army.mil!grassu-list at uxc.cso.uiuc.ed
u
> Subject: v.to.rast on small areas
> Content-Length: 433
> 
> It appears that v.to.rast will not create a raster area
> from a very small vect area, such as less than .2 acres.
> I am guessing this is because the area does not fill even 
> one pixel.  I have 14 areas that will not "rasterize" on
> a NWI wetlands map.  Is there any way I can get around
> this problem to complete my map.
> 
> Thanks.
> 
> 
> Carla Elenz
> Environmental Specialist
> Camp Grayling, MI
> (517) 348-7621 ext 3306
> elenz at osiris.cso.uiuc.edu
>