Dear Micha
thanks for your suggestion.
Actually, that's is what I usually do. However, I am not really
interested in the catchment of the endpoints of the edges but in
sampling points lying at the streams. If a point lies within the dem
cell of the outlet, which can be a confluence of two streams, the
coordinate approach will result in the catchment of both confluences,
although the point lies just at one of them. That's why I came up with
the idea of summing up the subcatchments of only the relevant branch of
the stream network.
Maybe there are other thoughts on that?
Mira
On 05/04/17 15:25, Micha Silver wrote:
On 04/05/2017 03:22 PM, Mira Kattwinkel wrote:
Dear List,
I am using r.mask to create a new raster map that only contains
certain categories given in 'maskcats'. Then, I use r.mapcalc to save
the map under a new name and (to be on the save side) delete the MASK
with r.mask flag '-r'. I do this in a loop and it works fine until a
case when the number of categories to combine is 213 (trail and error
lead to 106 as the maximum number that works fine). Flag 'verbose'
gives the message that a MASK was created, but none is there. The
problem arises in both cases when I directly use Grass or through R
using execGrass.
Is there a limit in the number of categories that can be passed to
r.mask? I did not find any hint about that. Additionally, I wonder
why there is no error message but in the contrary one that tells me
that a MASK was created even when it failed.
In case the details are important (or if anybody has a better idea
how to achieve what I want): I have a raster map of subcatchemts
belonging to stream segments created with r.stream.basins. For the
endpoints of segments, I want to combine these subcatchments to a
total catchment raster map containing all upstream catchments.
If you have the endpoint of of the outlet segment, you might use that
as the "coordinates" parameter to r.stream.basins to create a single
large drainage basin. Then use that as the mask to get out the
subcatchments.
Thanks a lot,
Mira
--
Micha Silver
cell: +972-523-665918
--
Dr. Mira Kattwinkel
Quantitative Landscape Ecology
Institute for Environmental Sciences
University of Koblenz-Landau
Fortstraße 7
76829 Landau
Germany
Phone: + 49 6341 280-31553
Office: Building I, Room 2.02
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