AnswerBun.com

GRASS 7.8.3 problem with r.watershed and r.water.outlet

Geographic Information Systems Asked by Elena Aragona on December 5, 2020

I need to find the basin of a small river and this is what I did:

  • I found the drainage direction with r.watershed
  • I used r.water.outlet to find the basin for the coordinates of the water outlet point.

The problem is that this works for some bigger rivers but not for the one I need.

I saw that in the output "stream" of r.watershed my river doesn’t appear, could be it the problem? What can I do? Here the images of "accumulation" form r.watershe in which you can see the river and the images of "stream" where there river doesn’t appear.

enter image description here

enter image description here

One Answer

Are you sure that the drainage point lies exactly on a stream line? Zoom in close to the streams raster (from r.watershed) and get the X-Y coordinates of the center of one pixel on the streams line. Then use those coordinates, together with the drainage direction raster as input to r.water.outlet, and it should work.

If you want to see the actual stream lines in your small basin, you'll need to rerun r.watershed with a lower threshold value.

Answered by Micha on December 5, 2020

Add your own answers!

Related Questions

Finding points along line closest to known point

1  Asked on April 21, 2021 by henrik-lied

         

Implementing QgsTasks in a Plugin

0  Asked on April 21, 2021

 

Intersect points and polygons

1  Asked on April 21, 2021 by tnt

   

QGIS link to web server

0  Asked on April 21, 2021

 

Change rasters’ z value to minus (Below sealeave)

1  Asked on April 20, 2021 by communityecologist

         

Combining Layers by Weighting Attributes

0  Asked on April 20, 2021 by cole

   

Why can QGIS open MrSid files, but GDAL cannot?

1  Asked on April 20, 2021 by maxfield-green

   

Semi-Automatic Classification Plugin error

0  Asked on April 20, 2021 by yu-lan

   

Ask a Question

Get help from others!

© 2022 AnswerBun.com. All rights reserved. Sites we Love: PCI Database, MenuIva, UKBizDB, Menu Kuliner, Sharing RPP, SolveDir