[GRASS-user] How to remove small closed lines

[Rabotin Michael]

So when you have identified in your lines map which lines are closed or 
not (with the coordinates equality), you can compute the length of all 
the lines and remove the closed ones which are under the threshold you 
want with v.extract. You can have two columns in your line map, one 
which identify if the line is closed or not and one whith the length. 
And you can used the v.extract command with where="coltag="closed" AND 
collength<xxx"

Mick


Le 06/11/2013 17:23, BLANDENIER Lucien a écrit :
> In fact I need to remove some of the closed line according to their length.
>
> Normally v.clean is able to remove small line with a threshold but it is not working for closed lines... I was wondering if there is an easy way to do this. Or maybe is there a possibility to cut the "closed" lines
>
> regards
>
>
> ________________________________
> De : Rabotin Michael [rabotin at supagro.inra.fr]
> Envoyé : mercredi 6 novembre 2013 16:54
> À : grass-user at lists.osgeo.org
> Cc : BLANDENIER Lucien
> Objet : Re: [GRASS-user] How to remove small closed lines
>
> Hi, maybe you can identify your closed lines  with v.to.db command and the coordinate of the start point and the end point
>
> v.to.db map=mylines option=end type=line col=coordEnd
> v.to.db map=mylines option=start type=line col=coordStart
>
>
> and tests if the coordinates of the startNode and the EndNode are equals, the line is closed and you can tag your lines .
> And use after the v.extract command to extract only the lines which are not closed.
>
> Hope it can be helpful
>
> Michael
>
>
> Le 06/11/2013 16:25, grass-user-request at lists.osgeo.org<mailto:grass-user-request at lists.osgeo.org> a écrit :
>
> Date: Wed, 6 Nov 2013 12:59:29 +0000
> From: BLANDENIER Lucien <lucien.blandenier at unine.ch><mailto:lucien.blandenier at unine.ch>
> To: "grass-user at lists.osgeo.org"<mailto:grass-user at lists.osgeo.org> <grass-user at lists.osgeo.org><mailto:grass-user at lists.osgeo.org>
> Subject: [GRASS-user] How to remove small closed lines
> Message-ID:
>          <84F1DDBD03D55944AA4E63A2FE5EADE5530AB5EB at MAIL-MBX-05.UNINE.CH><mailto:84F1DDBD03D55944AA4E63A2FE5EADE5530AB5EB at MAIL-MBX-05.UNINE.CH>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi,
>
> I would like to know how to remove automatically small circles (closed lines, not area). I've tried with v.clean and v.generalize but I just get to remove line which are not closed.
>
>
> Regards
>
>
> Lucien
>
>
> --
> [INRA]<http://www.inra.fr>
>
> Michael Rabotin
> Ingénieur d'Etude SIG / GIS Engineer
> michael.rabotin at supagro.inra.fr<mailto:#>
> UMR LISAH - Centre de Montpellier
> Tèl. : +33 (0)4 99 61 23 85
> Mobile : +33 (0)6 76 45 46 83
> Fax : +33 (0)4 67 63 26 14
>
> Bat 24 - 2 place Pierre Viala
> 34060 Montpellier cedex 2
> France
> www.inra.fr<http://www.inra.fr> www.openfluid-project.org<http://www.openfluid-project.org>
>
>


-- 
Signature electronique
INRA <http://www.inra.fr>
*Michael Rabotin*
*Ingénieur d'Etude SIG / GIS Engineer*
michael.rabotin at supagro.inra.fr <mailto:#>
*UMR LISAH - Centre de Montpellier*
Tèl. : +33 (0)4 99 61 23 85
Mobile : +33 (0)6 76 45 46 83
Fax : +33 (0)4 67 63 26 14

Bat 24 - 2 place Pierre Viala
34060 Montpellier cedex 2
France
www.inra.fr <http://www.inra.fr> 	www.openfluid-project.org 
<http://www.openfluid-project.org>

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