Questions tagged [r.watershed]

r.watershed is an R module that calculates hydrological parameters and RUSLE factors.

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how can interior basins be modified in the r.watershed GRASS function?

This is a follow up question to How does "Minimum Size of Exterior Watershed Basin" work in r.watershed command in qgis 2.18.12? I understood that the threshold parameter is used to ...
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0answers
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GRASS GIS: Getting know about stream power index (SPI) computation by r.watershed function

I need to know exact way how stream power index (SPI) is computed by module r.watershed. On the help page is that SPI is α * tan(β), where: α is cumulative upslope area draining through a point per ...
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1answer
311 views

Watershed Delineation Loop - r.water.outlet resulting in NAN area while snapped

I am attempting to create multiple watershed delineations for stations within a CSV file. I have files for flow direction (raster with a cell size of 30m), flow accumulation(raster with a cell size of ...
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1answer
747 views

How does “Minimum Size of Exterior Watershed Basin” work in r.watershed command in qgis 2.18.12?

I have delineated the watersheds from DEM using r.watershed command. I have specified the Minimum Size of Exterior Watershed Basin as 1500. I have read the description of r.watershed as well. I am not ...
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1answer
142 views

Getting error while executing grass algorithms from PyQGIS

I am trying to run r.water.outlet by PyQGIS but getting grass folder not configured error I have QGIS 2.18 installed and Grass is not installed on windows 10 and I am able to use r.water.outlet from ...
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1answer
77 views

R.Watershed unable to process a large geotiff (dem) file

I have a large geotiff file (dem) that I am planning to use with r.watershed to delineate a very large drainage basin. The file is 142 GB. When I try to run r.watershed after a few second it gives me ...
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1answer
635 views

Can't get GRASS r.water.outlet to work

I'm new to GRASS. We want to delineate a watershed using the LIDAR data we have our hands on. I tried to follow several procedures to do so, but despite all my efforts, I can only get it to select a ...
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2answers
626 views

G_malloc error while running r.watershed in GRASS 7.0.4

I tried to use r.watershed function in GRASS GIS, and got an error message ERROR: G_malloc: unable to allocate 3837384596 bytes of memory at raster/r.watershed/ram/init_vars.c:146 before getting the ...