[GRASS-user] r.watershed: Problems Using

[Rich Shepard]

   Running r.watershed failed:

GRASS 6.4.0svn (Oregon):/usr4/grassbase > r.watershed -m elev=aber5m
accum=aber5m.ws.accum drain=aber5m.drain basin=aber5m.basin
stream=aber5m.streams visual=aber5m.visual thresh=1500 --o
SECTION 1 beginning: Initiating Variables. 5 sections total.
WARNING: No such file or directory
WARNING: seg_open(): could not write segment file
SECTION 1b (of 5): Determining Offmap Flow.
WARNING: Subprocess failed with exit code 8
WARNING: category information for [aber5m.ws.accum] in [beaver_lake]
          missing or invalid
WARNING: category information for [aber5m.drain] in [beaver_lake] missing
          or invalid
WARNING: category information for [aber5m.basin] in [beaver_lake] missing
          or invalid
WARNING: category information for [aber5m.streams] in [beaver_lake] missing
          or invalid
WARNING: category information for [aber5m.visual] in [beaver_lake] missing
          or invalid

   The warnings at the end must be spurious since these are all output maps
and not created until further along the module run.

   The first three WARNINGs look to me to be ERRORs instead. How to I learn
why the module failed?

   Also, what guidelines does one apply to determine an appropriate threshold
value for an exterior watershed basin?

Rich