[GRASSLIST:5546] Re: v.mkgrid extract grid sections

[Sandro Klippel]

try v.clean ...

Em Qui 27 Jan 2005 16:24, Dylan Beaudette escreveu:
> Radim,
>
> Thanks for the idea... but doing v.extract type=area leaves me with only
> the centroids for each grid cell...
>
> is there anyway to convert a set of line segments into a polygon?
>
> thanks!
>
> Dylan
>
> On Thursday 27 January 2005 12:14 am, Radim Blazek wrote:
> > Use v.extract type=area
> >
> > Radim
> >
> > Dylan Beaudette wrote:
> > > On Wednesday 26 January 2005 06:09 pm, Hamish wrote:
> > >>>I have used v.mkgrid (GRASS6-CVS) in the past to make vector grids,
> > >>>and all  has been well.
> > >>
> > >>..
> > >>
> > >>>However, this morning I tried to extract a single square from the
> > >>>output from  v.mkgrid, and was only able to get either a single
> > >>>centroid (almost correct),  or the entire boundary (not good). Since
> > >>>the boundaries do not have CATs,  there is no way for me to extract a
> > >>>single boundary...
> > >>
> > >>..
> > >>
> > >>>Any ideas?
> > >>
> > >>what about
> > >>
> > >>  v.category type=boundary option=add
> > >>
> > >>to add category numbers to the boundaries?
> > >
> > > Thanks! ... this gives the boundaries CATs... but for some reason, each
> > > grid square is made up of about 8 line segments (3 for top and bottom
> > > lines, 1 for each vertical line)...
> > >
> > > My hope is that i can make each grid "cell" into a discreet polygon,
> > > that can be used to set the region -- i.e. so that i can accurately
> > > subsample a larger map.
> > >
> > > thanks!