[GRASS-user] v.patch and cat values

[Tyler Smith]

On Wed, Mar 07, 2007 at 04:10:54PM +1300, Hamish wrote:
> > 
> > Is there a way to re-assign cat numbers to the areas in my map so that
> > I can give them unique names? Ideally without having to repeat the
> > v.patch step, as I've spent a couple hours doing d.what.rast editing!
> 
> 
> when it patches them, does it create two layers? (no idea, but it might)
> 
> see v.reclass to reassign the cat column.
> see v.to.db to populate columns from map features, also v.distance.
> 
Thanks both of you for your suggestions. I used v.category to add a
new cat, which I had to add in a separate layer, and then added it to
the database for the vector:

v.category input=na_ecoregions output=na_ecoregions_cats option=add
 layer=3 --overwrite
v.to.db map=na_ecoregions_cats layer=3 option=cat
v.db.connect map=na_ecoregions_cats layer=3 table=na_ecoregions_cats

 The output of a
typical d.what.vect is:

map: 'select_ecoregions'
mapset: 'tyler'
feature type: Centroid

Layer: 1
category: 77
driver: dbf
database: /home/tyler/grassdata/worldclim/tyler/dbf/
table: select_ecoregions_1
key column: cat
cat :  77 
reg_name :  Northern Lakes and Forests 

Layer: 3
category: 912
driver: dbf
database: /home/tyler/grassdata/worldclim/tyler/dbf/
table: select_ecoregions_3
key column: cat
cat :  912 
reg_name :  

Is there a way to transfer the reg_name field from layer 1 to layer 3?
That would leave me with a handful of areas to correct manually. I
tried to use r.reclass for this:

v.reclass input=select_ecoregions output=sel_ecoreg2 column=cat
 layer=3

This didn't work. The reclassed map appears to be the same as the
original map.


-- 
Regards,

Tyler Smith