[GRASS-user] selecting upstream river segments

[Markus Neteler]

Hi Ivan,

please see
http://www.nabble.com/Streams-extraction-from-streams-map-td10267212.html#a10306465

Markus

On Mon, Apr 21, 2008 at 8:58 AM, ivan marchesini <marchesini at unipg.it> wrote:
> Dear Grass users,
>
>  I have a vector stream network map of a single basin (so only a stream
>  "tree")...
>
>  each stream segment is correctly oriented downstream (the direction of
>  each vector is from higher to lower elevation..)
>
>  I would like to select a random segment of the "tree" and automatically
>  obtain only the upstream segments..
>  i.e. I would like to obtain a new map containing only the upstream
>  stream segments of the selected one... (that is the same of removing
>  those downstream)
>
>  obviously I must implement this process into a shell script...
>
>  Could you suggest a simple way to solve this little problem?
>  Can I use the direction of the vectors to solve this problem?
>
>  Many thanks
>
>  Ivan
>
>
>
>
>  --
>  Ti prego di cercare di non inviarmi files .dwg, .doc, .xls, .ppt.
>  Preferisco formati liberi.
>  Please try to avoid to send me .dwg, .doc, .xls, .ppt files.
>  I prefer free formats.
>  http://it.wikipedia.org/wiki/Formato_aperto
>  http://en.wikipedia.org/wiki/Open_format
>
>  Ivan Marchesini
>  Department of Civil and Environmental Engineering
>  University of Perugia
>  Via G. Duranti 93/a
>  06125
>  Perugia (Italy)
>  Socio fondatore GFOSS "Geospatial Free and Open Source Software" http://www.gfoss.it
>  e-mail: marchesini at unipg.it
>         ivan.marchesini at gmail.com
>  tel: +39(0)755853760
>  fax (university): +39(0)755853756
>  fax (home): +39(0)5782830887
>  jabber: geoivan73 at jabber.org
>
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