v.patch

[Susan Huse]

> From grass-lists-owner at max.cecer.army.mil Thu Jul 22 07:20:56 1993
> Date: Thu, 22 Jul 93 10:08:10 EDT
> From: albanir at ocean.rutgers.edu (Alan Albanir)
> Sender: grass-lists-owner at max.cecer.army.mil
> Reply-To: grassu-list at max.cecer.army.mil
> To: grassu-list at max.cecer.army.mil
> Subject: v.patch
> Content-Length: 550
> 
> 
>         We have two 7.5 minute quad based vector maps.  When we use
> v.patch to join these maps, we get unattached labels.  When we adjust
> the snapping threshold in v.support, we get the maps to edgematch 
> correctly, but we get more unattached labels and labels that dont show
> up anywhere.  When the maps are seperate, they seem to be fine showing
> no errors in v.digit or support.
>         We are able to bring these maps into arc/info and patch them 
> together just fine, but we dont want to keep doing this. Any help 
> would be appreciated.
> 
> 				ALAN
> 


Have you tried running

	v.spag -i map=mapname threshold=0

If your quads have the outline of the quad boundary, then patching them
will give double lines along the patch seam.  Double lines will cause
point to area failures.  v.spag will get rid of the extras.  If you want 
to get rid of them all together you can use v.reclass with the -i
option, reclassing all categories to themselves (1=1, 2=2, etc.)  That will 
dissolve the internal quad boundaries.  I generally get double labels 
from that, but so long as the labels are the SAME, it doesn't hurt 
anything, and you can get rid of the extra label in v.digit.