Hi,
2008/2/10, Guido Lorenz <[EMAIL PROTECTED]>:
> I am experiencing some trouble with extracting (and/or displaying) a
> vector layer, based on a 2nd database connection (GRASS 6.3svn,
> PostgreSQL 8.26). Viewing the output from v.extract, it can be
> seen that the table connection is correctly recognised and a
> sql-selection is performed without errors. Nevertheless, the topology
> of the new output vector generated indicates that there are any
> vector elements (see example 1). The same command, but referred to
> the 1st database table (the original one) gives a correct output
> vector layer (see example 2).
>
> Both associated tables have the same identifier column (cat),
> defined as primary key and index column in PostgreSQL. The v.info
> command shows, that both tables are apparently well connected to
> the vector layer.
> example 1:
> v.extract [EMAIL PROTECTED] output=test5
> type=point,line,boundary,centroid,area,face layer=2 new=-1 {where=cat >
> 1} --overwrite
> log:
> Vector map <test5> already exists and will be overwritten
> Load categories from the database (table = geo.test3, db =
> soils2006).
> 40 categories loaded from the database
> Building topology ...
> Registering lines:
> 0 primitives registered
> Building areas:
> 0 areas built
> 0 isles built
> Attaching islands:
> Attaching centroids: Topology was built.
> Number of nodes : 0
> Number of primitives: 0
> Number of points : 0
> Number of lines : 0
> Number of boundaries: 0
> Number of centroids : 0
> Number of areas : 0
> Number of isles : 0
> Writing attributes...
it seems there are no categories in the second layer, try
v.category [EMAIL PROTECTED] opt=print layer=2
you can use v.category or v.digit module to add categories to layer 2.
Regards, Martin
--
Martin Landa <landa.martin gmail.com> * http://gama.fsv.cvut.cz/~landa *
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