[GRASS-user] remove duplicate points

[Markus Metz]

On Thu, Jul 7, 2016 at 7:32 PM, Daniel Torres <nobeeakon at gmail.com> wrote:
> Hi everybody,
> I would like to get the nodes of a grid, I have managed to get the nodes,
> but do not understand how to remove duplicate points. After running "v.clean
> [...] tool=rmdpl " I get the right number of points, however, in the
> database the number of features continues to be the same as before v.clean.
>
> The manual of v.clean says:
> "rmdupl: remove duplicate geometry features (pay attention to categories!)"
> Does that means that v.clean preserves features with different cat numbers?,

No, features with identical coordinates but different categories are
merged into one feature with multiple categories.

> and that one feature can have more than one attribute assigned in a single
> table?

Yes. If you don't need the categories, you can delete them with
v.category and afterwards add one single unique category to each
feature with v.category. The link to attributes gets lost of course.

HTH,

Markus M

>
>
> Thank you very much
> Daniel
>
> Ex.
>
> # In nc_spm_08
> g.region rast=lsat5_1987_10
> v.mkgrid grid=4,4 map=grid44
> v.to.lines input=grid44 output=grid44lines
> v.to.points input=grid44lines output=grid44points use=node
> v.info -t grid44points
>     nodes=0
>     points=80
>     ....
> v.clean input=grid44points output=grid44pointsclean tool=rmdupl
> v.info -t grid44pointsclean
>    nodes=0
>    points=25
>    ...
>    primitives=25
> g.gui.dbmgr grid44pointsclean2
>
>
>
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