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

[nikos.alexandris at felis.uni-freiburg.de]

Sorry for typo's!

On Thu, 17 Jan 2008 13:02:54 +0100
 nikos.alexandris at felis.uni-freiburg.de wrote:

I just wonder how was the tile-patching and dissolving
 (of CORINE shapefile(s)) done, as described in
v.dissolve's help text?


Were the file's "CODE_00" column different than "TEXT" ?

> But anyway is good to make things as much as possible
> more
> transparent. I learned a lot from this small story.
> 
> Thanks!
> 
> On Wed, 16 Jan 2008 22:26:45 -0500
>  "Patton, Eric" <epatton at nrcan.gc.ca> wrote:
> > Eric Patton wrote:
> > > > Just a clarification...so it's the case that the
> > column parameter
> > > > in v.dissolve must always be of type integer, and
> > *only* integer?
> > 
> > Hamish:
> > >The v.dissolve script with dissolve based on a column
> > currently
> > >requires that column to be of type integer. We should
> > probably add a
> > >check in the script for that (v.info -c).
> > 
> > Ok, that's what I thought; thanks. I wanted to make
> sure
> > before I added a hint in the docs.
> > Actually, I think Nikos mentioned something about
> writing
> > up a hint about it, so I'll hold off.
> > 
> > >It would be possible to add any type of column to
> > v.dissolve with unix
> > >tools 'db.select | sort | uniq | nl' then create a new
> > table with the
> > >unique attributes + sequential integer column, then
> > v.reclass as
> > >before.
> > 
> > >or add a new column to (a copy of) the existing table
> > (v.db.addcol) and
> > >populate it with a 'db.select | sort | uniq' loop and
> > v.db.update, or
> > >SQL + db.execute << "set DISOLVEKEY = $i where
> ATTRIBUTE
> > = '$VAL'"
> > >(sorry my SQL is not good but you may be the idea of
> > what I mean)
> > 
> > Cool. It's always amazing how powerful these little
> > command line tools can be.
> > 
> > ~ Eric.
> > 
> 
>                     
>                         .
>          Nikos Alexandris - Ph.D. Candidate
>                         .
>             Department of Remote Sensing
>                        and
>             Landscape Information Systems
>                      (FeLIS)
>                         .
>       Faculty of Forestry and Natural Environment
>           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
>                         .
> _______________________________________________
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                        .
         Nikos Alexandris - Ph.D. Candidate
                        .
            Department of Remote Sensing
                       and
            Landscape Information Systems
                     (FeLIS)
                        .
      Faculty of Forestry and Natural Environment
          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
                        .