[GRASSLIST:9436] v.extract and vector table

[Nick Cahill]

I'm trying to dissolve the boundaries between adjacent areas which  
have common attributes in their vector database. I understand that  
the best tool for this is v.extract. The maps are derived from vmap0  
political boundary coverages; the problem with these is that the maps  
were tiled, so regions span across adjacent ex-tiles, with the same  
names and other attributes. I'd like to end up with a single area and  
centroid for each region, with the original database attributes.

As a test I tried it with one regional unit, BURDUR. If I run

v.extract input=polbndr output=burdur  
type=point,line,boundary,centroid,area,face layer=1 new=-1  
where=a_nam='BURDUR' -d

with new=-1, it doesn't merge the two areas because the category  
values are different in the two areas. So I try assigning a new  
category:

v.extract input=polbndr output=burdur2  
type=point,line,boundary,centroid,area,face layer=1 new=500  
where=a_nam='BURDUR' -d

This merges the vectors properly, but this doesn't seem to create a  
new table for the newly created vector. The centroid has the proper  
category, but there is no table associated. Do I have to create a new  
table by hand and then link the vector to this table? Or is there an  
easier way to do this? I don't look forward to doing each  
administrative unit which spans different tiles on these vmap0 maps.

Any help would be gratefully appreciated.

Nick Cahill