Thanks Tom,
this is what I meant by looping over each subbasin, but that is exactly
what I would like to avoid as it would take a lot of time for 1000+
subbasins and I dont really need all the other analysis.
Cheers,
Michel
On 02/16/2014 05:58 PM, Thomas Adams wrote:
Michel,
If you do what you suggest, but first apply a MASK using each
subbasin; so, when you calculate the statistics, they will be for one
subbasin at a time; with a very simple script you could loop through
each subbasin.
I hope this helps.
Cheers!
Tom
On Sun, Feb 16, 2014 at 11:07 AM, Michel Wortmann
<[email protected] <mailto:[email protected]>> wrote:
Hi list,
I'm looking for a way to calculate the main channel length and
width for a large number of subbasins within a river basin. I
understand that the r.stream.* addon / R.basin gives me the main
channel length along with a tone of other statistics but only for
one catchment. Of course, I could loop over all my subbasins and
calculate the statistics one by one, but I fear that will be time
consuming and I dont actually need all the other analysis.
I have got an efficient way to calculate the mainstream for each
subbasin as a vector, but I'm struggling to get from there to the
distance of the longest segment in each subbasin. Maybe someone
has an idea to complete this idea of a work flow:
raster=mainstreams (thinned raster with unique categories for each
subbasin)
r.to.vect to vectorise, this unfortunately gives me line segments
crossing over subbasin boundaries
somehow make stream segments from each subbasin
v.to.db to measure the distance of each line segment
choose the longest distance for each subbasin
Any suggestions/help would be much appreciated.
Regards,
Michel
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