[GRASS-user] Contour lines extraction

[Odoardo Zecca]

Thank you Maciej.

It seem to work only for points, but not for lines. Maybe this doesn't work
for lines because they don't have a unique x and y but only a unique z, or
am I doing something wrong?

On 7/20/06, Maciej Sieczka <tutey at o2.pl> wrote:
>
> Odoardo Zecca napisa?(a):
> > Hi all,
> > I need to extract some contour lines from a vector map (imported with
> > v.in.dwg -z). While  I can do this on the base of their category, it
> would
> > be easier to directly select the desired elevations, but I don't know
> > how to refer to them.
>
> Maybe
>
> add a x,y,z columns to your table (v.db.addcol)
>
> populate it with coords (v.to.db option=coor)
>
> now z coord is stored in table
>
> ?
>
> Maciek
>
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