[GRASSLIST:920] Re: Planning swath bathymetry surveys

David Finlayson david.p.finlayson at gmail.com
Wed Apr 26 20:07:34 EDT 2006


The link should be:

http://david.p.finlayson.googlepages.com/swathwidth



On 4/26/06, Hamish <hamish_nospam at yahoo.com> wrote:
> > > > > 1) "It appears that v.buffer buffers the nodes on the line
> > > > > segments rather than drawing parallel lines at the appropriate
> > > > > distance from the centerline."
> > > > >
> > > > > I don't think that is right, if the input feature is a line.
> > > >
> > > > I guess statement 1) is somewhat right. See the attached
> > > > screendump. Red is the input lines, black is the output of the
> > > > command:
> > > >
> > > > v.buffer input=x_extr output=buffer type=boundary layer=1
> > > > buffer=100 scale=1.0 tolerance=0.01 debug=buffer
> > >
> > > I don't see the problem? Sure as part of the processing it buffers
> > > about nodes, but after a disolve common boundaries cleaning step the
> > > buffer looks correct between nodes as well? (see ski jump mid-right
> > > side of your image)
> >
> > Why does it buffer around nodes anyway while we want it to buffer
> > around lines (only)?
>
> I still do not follow exactly what you are asking for...
>
> For a single line, you want the buffer to have square ends, not rounded?
> Distance from end point of a road is still distance from the road, yes?
>
> Node is always on the line, so it doesn't matter if it buffers along
> them as well as the line.  ???
>
>
> Hamish
>
>


--
David Finlayson




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