[GRASSLIST:2586] stream layer artifacts

[Christopher Fonnesbeck]

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

--
Christopher J. Fonnesbeck ( c h r i s @ f o n n e s b e c k . o r g )
Georgia Cooperative Fish & Wildlife Research Unit, University of Georgia
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: text/enriched
Size: 836 bytes
Desc: not available
Url : http://lists.osgeo.org/pipermail/grass-user/attachments/20040212/5e473cb6/attachment.bin