[GRASS-user] simple way to get Easting and Northing coordinates of stream outlet directly from r.watershed?

Tue Apr 26 10:03:44 PDT 2016

Hi Jim,
I've used r.stream.extract a fair amount.  It produces a downstream-oriented vector. In layer 2 of the output stream vector map the "cat" value of 2 indicates outlet points. See (https://grass.osgeo.org/grass64/manuals/addons/r.stream.extract.html) (note this is GRASS 6.4.4 but should be similar for 7.x)

Chris Bartolomei P.E.
Engineer/Scientist
ENSCO, Inc.
4849 North Wickham Road
Melbourne, FL 32940 (official office)
5038 Park Rim Drive
San Diego, CA 92117 (home office)
(858) 581-3005
bartolomei.chris at ensco.com
________________________________________
From: grass-user [grass-user-bounces at lists.osgeo.org] On Behalf Of Jim Maas [j.maas at uea.ac.uk]
Sent: Tuesday, April 26, 2016 6:43 AM
To: Blumentrath, Stefan; grass-user at lists.osgeo.org
Subject: Re: [GRASS-user] simple way to get Easting and Northing coordinates of stream outlet directly from r.watershed?

Hi Stefan,

Thanks for this.  I've had a look but not tried it yet.  Just for me to
clarify, are you suggesting that:

 1. r.stream.basins will somehow produce and output the Easting and
    Northing values of the overall outlet?
 2. r.stream.basins, will replace most of this workflow and thus the
    Eastings and Northings will not be required explicitly?

In the case of 1, I can't quite see how it will output these values?

Thanks a bunch,

J

On 26/04/16 14:02, Blumentrath, Stefan wrote:
> Hi,
>
> Did you consider using:
> https://urldefense.proofpoint.com/v2/url?u=https-3A__grass.osgeo.org_grass70_manuals_addons_r.stream.basins.html&d=CwIGaQ&c=DsZY2bea7iNIzyp-7sZ0t0F2UfNQZUfZhEPCv_2wBI0&r=O31ltou6ygJL2Y01kQyNJJD2kiILIsbyz2V0Hn4lFUY&m=uLWb19rS_9IrFOaSAkQeNfJ1qv_6HGtvzKSj16TxYN8&s=iQFFPiu77Qwcm1tmAu9f-H9-0rZQOG8HFgkRIUXvgs0&e=
> ?
>
> Cheers
> Stefan
>
> -----Original Message-----
> From: grass-user [mailto:grass-user-bounces at lists.osgeo.org] On Behalf Of Jim Maas
> Sent: 26. april 2016 14:28
> To: grass-user at lists.osgeo.org
> Subject: [GRASS-user] simple way to get Easting and Northing coordinates of stream outlet directly from r.watershed?
>
> I'm using GRASS 7.0.3 (text) on Ubuntu Linux, and running it either from a bash shell script or from an R file.
>
> I've worked out a workflow that does what I want, but it is very long and convoluted, so I'm wondering if there is a simple way to extract the Easting and Northing coordinates of the lowest point on the stream network, such that I can then use them as inputs for r.water.outlet?
>
> Here is my workflow, realise it is long
>
>   1. run r.watershed to get drainage, streams, and basin  2. run r.stream.order to calculate strahler order and get strahler
>      raster map
>   3. use r.stats and some bash code to extract highest strahler number
>      from the strahler map
>   4. use r.mapcalc .... not sure why, inherited this bit from someone!
>   5. use r.stats to get data from stream dem into a text file  6. use some bash and awk code to extract the Easting and Northing
>      values of the lowest point in the text file created from the stream dem  7. use r.water.outlet to create new drainage map for the basin  8. use r.lfp  to calculate longest flow path, also uses the Northing
>      and Easting values of the outflow point
>
>
> So I guess what I'm looking for is a simpler way to get the Northing and Easting values of the lowest point, directly from r.watershed or something analogous.
>
> All suggestions most welcome. Thanks
> J
>
> --
> Dr. Jim Maas
> University of East Anglia
>
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--
Dr. Jim Maas
University of East Anglia

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