[GRASS-user] "ladders" in watershed delineation

Micha Silver micha at arava.co.il
Tue Aug 4 07:32:24 EDT 2009


Markus Metz wrote:
>
> Micha Silver wrote:
>> Markus Metz wrote:
>>
>>> These single-cell strings in basins, did you get them with SFD or 
>>> MFD mode? If MFD mode, what convergence factor did you use?
>>>
>> My watershed delineation was done with r.watershed, not r.terraflow, 
>> so IIUC it's SFD.  I didn't see any "braided" streams in the output.
> r.watershed in 6.5+ can do MFD which reduces these single-cell strings 
> substantially. I would recommend MFD over SFD for anything with 30m 
> resolution or higher, not much gained for 90m or coarser. Results are 
> generally more accurate with MFD for high resolution (<= 30m) DEMs.
>
Markus:
Thanks for your time.
So, bottom line, I'll look forward to updating to 6.5 or 7...
> Markus M
>



More information about the grass-user mailing list