[GRASS5] GRASS5.7: trouble converting shapefile to postgis with v.convert

[Markus Neteler]

On Fri, Dec 05, 2003 at 05:38:44PM +0100, Moritz Lennert wrote:
> Radim Blazek said:
> > On Thursday 04 December 2003 19:17, Moritz Lennert wrote:
> >> Hello,
> >>
> >> I have a shapefile registered in GRASS5.7:
> >>
> >> *******
> >> GRASS 5.7.-cvs:~ > g.list vect
> >> ----------------------------------------------
> >> vector files available in mapset mlennert:
> >> communes.shp
> >>
> >> ----------------------------------------------
> >> ************
> >>
> >> I can display and query this file without any problems.
> >>
> >> It is connected to a dbf file:
> >>
> >> *************
> >> GRASS 5.7.-cvs:~ > v.db.connect -p communes.shp
> >> Vector map <communes.shp> is connected by:
> >> field <1> table <communes> in database </home>
> >> through driver <shp> with key <shp_fid>
> >> **************
> >>
> >> Following the tutorial, I tried to store this map in PostGIS format:
> >>
> >> *************
> >> GRASS 5.7.-cvs:~ > v.database driver=pg database="dbname=digit_belgium"
> >> GRASS 5.7.-cvs:~ > v.convert input=communes.shp output=communes
> >> *************
> >>
> >> but I got the error message: "ERROR: Input vector was not found."
> >>
> >> What am I doing wrong ?
> >
> > v.convert converts old GRASS vector files (GRASS 4.0,5.0) to 5.1/7 format.
> > v.database is used to set the database for attributes.
> > If you want to write a vector in PostGIS format, you have first set
> > the output vector format to PostGIS either in
> > v.format -> output format -> PostGIS
> > or by g.gisenv:
> > g.gisenv store=mapset set=GV_FORMAT=POSTGIS
> > g.gisenv store=mapset
> > set=GV_PGIS_DATABASE=host=liptakov,dbname=cimrman,user=jara
> >
> > Once you set vector format to PostGIS, all new vectors are written to the
> > database.
> > Attributes are by default written to dbf files, so until you set also
> > v.database driver=pg database="dbname=digit_belgium"
> > you get geometry in Postgres and attributes in dbf, isn't it funny?
> 
> 
> I did all these steps, just following the tutorial, but the problem was
> the usage of v.convert. May I conclude that the description in the
> tutorial at
> http://grass.itc.it/grass51/tutorial/geom_storage.html#PostGRASS is wrong
> then ?

Possibly yes. The tutorial *tries* to keep pace with the 5.7 development.
But that's not always possible due to (my) time constraints.
Sorry for any inconvenience, I am happy to receive corrections.
 
> > To convert the vector you can run g.copy for example, but that is not what
> > you want
> > as communes will be polygons and you have to clean such vector first.
> > I would recommend v.in.ogr as it does all the cleaning. See the statistics
> > about
> > areas at the end.
> >
> 
> So you would recommend this rather than just using the shp2pgsql program
> that comes with postgis ?

Note that areas are treated differently in PostGIS and PostGRASS (the latter
with pseudo-topology, correct me if I am wrong). So it will work only for
lines and points.

Markus