[GRASSLIST:5545] Re: v.mkgrid extract grid sections

[Dylan Beaudette]

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!

-- 
Dylan Beaudette
Soils and Biogeochemistry Graduate Group
University of California at Davis
530.754.7341