[GRASS-user] r.flow-> wrong result

GRASS GRASS user
,
1

Hello Grassdevelopers,

I try to run the r.flow module to get the flow path length of my Layer out.
The input Layer is a DEM with pixelsize 0.0083 and the selected CRS (EPSG:32646, WGS 84/ UTM zone 46).
First of all I generated a depressionless elevation with saga:fill sinks.

If I start the function, it runs and I get the three Outputlayer, but they are wrong. → pictures see below

My Data: Win 10, Qgis 2.16.1 with Grass 7 Plugin.
I have the same problem if run r.flow in Grass.
Which additional steps I have to do ?

Thanks in advance and best wishes,

Eva

Picture 1: accumulation generated with r.flow Picture 2: accumulation generated trough r.watershed

Picture 3: generated flow path length trough r.flow

2

On 21/12/17 15:13, Eva Schindele wrote:

Hello Grassdevelopers,

I try to run the r.flow module to get the flow path length of my Layer out.
The input Layer is a DEM with pixelsize 0.0083 and the selected CRS (EPSG:32646, WGS 84/ UTM zone 46).
First of all I generated a depressionless elevation with saga:fill sinks.

AFAIK, you should fill sinks before using r.flow. Try without that step.

If I start the function, it runs and I get the three Outputlayer, but they are wrong. --> pictures see below

It might help to explain what you expect as output and why the one you get is wrong. Just from looking at your maps it's not easy to understand, especially since we do not get to see the original DEM.

Moritz