[GRASS-user] problem with v.db.update and categories

[tommaso]

Ok, now can I add the missing categories in dbf table with:
v.to.db map='polygons' type='centroid' option='cat'
But the update command is still failing:
v.db.update map=polygons col=building value=3.0

The new categories in dbf table have still empty 'building' attributes...



On Wed, 03 Dec 2014 09:42:28 +0100, tommaso <tommasodb at googlemail.com>  
wrote:

> Hello, I'm trying to polygonize a lines layers. I imported the layer in
> grass with v.in.ogr as boundaries, then I attached the centroids with
> v.centroid.
> Probably because of the polygonize, some attribute are lost in in the
> output map, so I have to update the table to fix the attributes:
> v.db.update input='polygons' col=building, value='3.0'
>
> After the update, the table look fine with v.db.select: all record have
> the right value. But if I export the layer with ogr, some records do not
> have attributes at all. My export command looks so.
> v.out.ogr format='PostgreSQL' input='polygons' type='area'
> dsn='PG:dbname=test_project host=localhost' olayer='test_table'
> This warning is raise by v.to.ogr: WARNING: 8 features without  
> attributes were written
>
> I guess, the map categories are not synchronized with the database.
> v.categories returns 1018 results, while the map contains only 298  
> records:
> v.category polygons option=print | wc
>       1018    1018    5133
>
> Where are so many categories coming from? How can I synchronize map and
> database?
> Thanks, Tomm