[GRASS-user] Can't dissolve based on column?

[Martin Landa]

Hi,

I tried to dissolve vector map based on text column (varchar). Seems to work.

e.g.

v.db.addcol vegcover col="label1 varchar(250)"
echo "update vegcover set label1='a'" | db.execute
v.dissolve in=vegcover out=vc_dis --o col=label1

Martin

2008/1/16, Martin Landa <landa.martin at gmail.com>:
> Hi,
>
> 2008/1/16, Patton, Eric <epatton at nrcan.gc.ca>:
> > Just a clarification...so it's the case that the column parameter in v.dissolve must always be of type integer, and *only* integer?
>
> I don't see any reason why v.dissolve should support only integer
> columns as a key used to dissolve areas...
>
> (not tested v.dissolve)
>
> Martin
>
> > ~ Eric.
> >
> >
> > -----Original Message-----
> > From: grass-user-bounces at lists.osgeo.org on behalf of Nikos Alexandris
> > Sent: Wed 1/16/2008 3:41 PM
> > To: grass-user at lists.osgeo.org
> > Subject: Re: [GRASS-user] Can't dissolve based on column?
> >
> > Well... I suspected it had to do with the field type of the column
> > "CODE_00".
> >
> > Indeed... the column was "TEXT".
> >
> > After Daniels (Victoria) indications for a similar problem a change to
> > "integer" (using sqlitebrowser) solved the problem.
> >
> > I suggest a clarification about that in the man page of v.dissolved.
> >
> > Greets...
> >
> > P.S. Thank you Daniel
> > On Wed, 2008-01-16 at 16:52 +0100,
> > nikos.alexandris at felis.uni-freiburg.de wrote:
> > > All I try to do is a dissolve... and for:
> > >
> > > > v.dissolve input=clc00_clean output=clc00_dissolved
> > > col=CODE_00
> > >
> > > I get:
> > >
> > > DBMI-SQLite driver error:
> > > Cannot step:
> > > SQL logic error or missing database
> > >
> > > ERROR: Cannot fetch data
> > > ERROR: Unable to open vector map
> > > <clc00_dissolved_19941 at nik> on topology
> > >        level 2
> > > ERROR: Vector map <clc00_dissolved> not found in current
> > > mapset
> > > _______________________________________________
> > > grass-user mailing list
> > > grass-user at lists.osgeo.org
> > > http://lists.osgeo.org/mailman/listinfo/grass-user
> > --
> > Nikos Alexandris
> > .
> > Department of Remote Sensing & Landscape Information Systems
> > Faculty of Forestry & Environmental Sciences, Albert-Ludwigs-University Freiburg
> > .
> > Tel.  +49 (0) 761 203 3697 / Fax.  +49 (0) 761 203 3701 / Skype: Nikos.Alexandris
> > .
> > Address: Tennenbacher str. 4, D-79106 Freiburg i. Br., Germany
> >
> > _______________________________________________
> > grass-user mailing list
> > grass-user at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/grass-user
> >
>
>
> --
> Martin Landa <landa.martin at gmail.com> * http://gama.fsv.cvut.cz/~landa *
>


-- 
Martin Landa <landa.martin at gmail.com> * http://gama.fsv.cvut.cz/~landa *