[GRASSLIST:9592] Re: v.buffer: area boundary around line? Wanted: howto!

[Wolfgang Qual]

Hello Otto,
so you do not have the possibility to choose layer property "1_polygon" in
the "add grass vector layer dialog" of QGIS? I just tried the same command
(v.buffer in=roads out=roadsbuf buffer=20) and it looks ok. If I choose
0_polygon, only the area between the roads is drawn by QGIS.

Best regards,
Wolfgang


-----
> --- Ursprüngliche Nachricht ---
> Von: Otto Dassau <dassau at gdf-hannover.de>
> An: "Wolfgang Qual" <Wolfgang.Qual at gmx.net>
> Kopie: grasslist at baylor.edu
> Betreff: [GRASSLIST:9591] Re: v.buffer: area boundary around line? Wanted:
> howto!
> Datum: Wed, 21 Dec 2005 13:45:47 +0100
> 
> Am Mittwoch, 21. Dezember 2005 13:19 schrieb Wolfgang Qual:
> > Hi Otto, hi list.
> 
> Hi, 
> 
> the problems I described still exist with the spearfish dataset: 
> 
> v.buffer in=roads out=roadsbuf buffer=20 type=line
> v.buffer in=roads out=roadsbuf buffer=20 
> 
> it doesn't make a difference in the result.
> 
>   Otto
> 
> > Sorry, I think I was too fast...:
> > If I *do not specify "type"* in the command for v.buffer (v.buffer
> > in=ausschnitt out=buff_ausschnitt bufcol=gesamtbr)
> > I do get a correct result. I can add this vector to my QGIS-Map (Layer
> > 1_polygon) - works.
> > However: how can I display this in GRASS (d.mon, d.vect)? If I try
> d.vect,
> > the area inside the ring is also displayed!
> >
> > Wolfgang
> >
> > Buffer is drawn around the feature (line).
> >
> > > --- Ursprüngliche Nachricht ---
> > > Von: Otto Dassau <dassau at gdf-hannover.de>
> > > An: "Wolfgang Qual" <Wolfgang.Qual at gmx.net>
> > > Kopie: grasslist at baylor.edu
> > > Betreff: Re: [GRASSLIST:9588] v.buffer: area boundary around line?
> > > Wanted: howto!
> > > Datum: Wed, 21 Dec 2005 12:17:50 +0100
> > >
> > > Am Mittwoch, 21. Dezember 2005 11:22 schrieb Wolfgang Qual:
> > > > Hi List,
> > >
> > > Hi,
> > >
> > > > I tried to create a new area boundary around a line theme. Thought
> it
> > >
> > > would
> > >
> > > > be easy to do it like this:
> > > >
> > > > v.buffer in=ausschnitt out=buff_ausschnitt bufcol=gesamtbr
> > > > type=boundary
> > >
> > > I also tried with the spearfish location and a CVS snapshot from today
> > > and got
> > > similar strange results, where the lines (roads) describe a closed
> ring.
> > >
> > > v.buffer in=roads out=roadsbuf buffer=20 type=line
> > >
> > >
> > >   Otto
> > >
> > > > But GRASS won't create a new theme. After that, I tried to first
> create
> > >
> > > a
> > >
> > > > line buffer theme (works fine) and then convert it to a area
> boundary
> > >
> > > theme
> > >
> > > > using v.type. However, the new area boundary theme does not have the
> > >
> > > shape
> > >
> > > > of the line buffer theme.
> > > >
> > > > BTW, the line theme looks like this (street network):
> > > >
> > > >   ------------------
> > > >
> > > >     |         |       ...but I get s.th.      XXXXXXXXXXXX
> > > >     |         |       like this:              XXXXXXXXXXXX
> > > >
> > > >   --------------                              XXXXXXXXXXXX (area
> > > > inside)
> > > >
> > > > I would greatly appreciate to receive some hints...
> > > >
> > > >
> > > > Best wishes,
> > > > Wolfgang
> > >
> > > --
> > > GDF Hannover - Solutions for spatial data analysis and remote sensing
> > > Office Hannover     -      Mengendamm 16d    -     D - 30177 Hannover
> > > Internet: www.gdf-hannover.de,               Email:
> info at gdf-hannover.de
> > > Phone : ++49.(0)511.39088507,              Fax: ++49.(0)511.39088508
> 
> -- 
> GDF Hannover - Solutions for spatial data analysis and remote sensing
> Office Hannover     -      Mengendamm 16d    -     D - 30177 Hannover
> Internet: www.gdf-hannover.de,               Email: info at gdf-hannover.de
> Phone : ++49.(0)511.39088507,              Fax: ++49.(0)511.39088508
> 

-- 
GMX DSL-Flatrate 1 Jahr kostenlos* + WLAN-Router ab 0,- Euro*
Bis 31.12.2005 einsteigen! Infos unter: http://www.gmx.net/de/go/dsl