r.water programs / catchment derivation

N R A nra at cix.compulink.co.uk
Mon Jul 4 15:30:00 EDT 1994

A long while back, I was enquiring about the possibility of deriving a 
single catchment boundary from a DEM. I had a number of responses (many 

I've finally loaded the DEM for our region of the UK and am now in a 
position to try deriving.

I tried r.watershed (update 4) - program seems to work, certainly 
generates a number of basins which look approximately right. 

However I want to produce a single catchment, preferably by entering a 
single x,y coordinate (even better would be just pointing at the map cf. 
the 'd.where' program). Now someone mentioned some other 'r.water....' 
programs which might do the trick. One of these is 'r.water.outlet', 
which I downloaded from 'moon'. Is the 'drainage' output from 
'r.watershed' the same as the 'drainage' input to 'r.water.outlet' ?

If so, why do the basins I try to create, look to only consist of one or 
two cells ??

Thanks for any help,

Steve Culshaw
NRA North West
e-mail : nra at cix.compulink.co.uk (use this for general usage)
or         sculshaw at cix.compulink.co.uk (Private - only checked at best 

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