[GRASS-user] Re: r.water.outlet

[Daniel Victoria]

Going through my pile of old emails.... Here goes a delayed answer

To delineate basins the water outlet must by on top of a lino of high
acumulation (river) as is explained in the Notes section in
r.water.outlet manual [1]. A trick I saw being used was to user
r.distance (or v.distance) prior to r.water.outlet. I had a map with
the outlet of 100 basin but they were not in the right place. So I
used r.distance to find the nearest river cell close to each outlet
and then use r.water.outlet. For those comming from ESRI backgound,
this is the equivalent of the "snap pour point command".

Cheers
Daniel


[1] - http://grass.osgeo.org/gdp/html_grass64/r.water.outlet.html

On Thu, Nov 25, 2010 at 3:12 PM, Rich Shepard <rshepard at appl-ecosys.com> wrote:
> On Thu, 25 Nov 2010, skualos wrote:
>
>> I think I had the same problem. I was running r.water.outlet and getting a
>> plain raster. I found out that you must choose your point exactly on a
>> stream generated by r.watershed. Doing so solve my problem.
>
>  I think many of us learned this lesson the hard way. :-( I found that I
> needed to greatly enlarge the raster to place the outlet exactly on the
> stream.
>
> Rich
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