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

Jim Maas j.maas at uea.ac.uk
Tue Apr 26 05:27:56 PDT 2016


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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