[GRASSLIST:2598] Re: eliminating stream layer artifacts

[Radim Blazek]

On Friday 13 February 2004 15:53, Christopher Fonnesbeck wrote:
> I forgot to attach the graphics in my previous posting, so here it is
> again:
>
> I am trying to develop a reasonable stream layer based on the
> accumulation output from r.terraflow, but am ending up with odd
> artifacts and broken tributaries (see attached graphic). Here are the
> steps I have taken:
>
> - Run r.terraflow
> - Run r.mapcalc accum_x="if(abs(accum_d8)>x,1,null())", where x=5000
> for 10m DEM, x=555 for 30m DEM (trying to extract 50h accumulation
> streams)
> - Run r.thin to create single-cell width layer
> - Run r.to.vector to create vector layer
> - Run v.clean to remove spurs
>
> As you can see, however, the result is pretty unsatisfactory. Can
> anyone provide some advice on how this stream layer might be improved?
> I'm a bit stuck.
>
> Thanks in advance,
> Chris

Did you try v.clean tool=snap,break,rmdupl,rmdangle with some reasonable thresholds?

Radim