I'm regularly trying out different threshold values in r.watershed,
only to get different streams to be vectorized, flow accumulation and
drainage direction are not affected by the threshold option in
r.watershed. I have an idea for a new module that would take flow
accumulation and
Hamish wrote:
MMetz:
What exactly is wrong with topology? The existence of these dangles?
note the v.strahler help page makes special mention that if you used
r.watershed you should check the topology. Maybe it makes a bitter deal
out of that than is really the case?
S:
Maybe
Hi all
Hi Markus,
thanks for your answer. I found that the problem is in the topology of
the river network. I think that v.strahler produces many '0' because it
finds many little 'circles' in the stream vector. I tried to produce the
stream network both with r.watershed - r.to.vect and with
Hi..
If I well remember, the problems of 0 values in the category data were
related to braiding or similar artifacts deriving from rasterization
process
r.strahler used with threshold not too small should clean network and
solve the task...
here [1] (in italian.. sorry...) you can find some
Margherita Di Leo wrote:
Hi all
Hi Markus,
thanks for your answer. I found that the problem is in the topology of
the river network. I think that v.strahler produces many '0' because
it finds many little 'circles' in the stream vector. I tried to
produce the stream network both with
Markus I believe that would be invaluable. I will help in anyway that I can.
Stephen Sefick
On Thu, Jul 23, 2009 at 9:25 AM, Markus
Metzmarkus.metz.gisw...@googlemail.com wrote:
Margherita Di Leo wrote:
Hi all
Hi Markus,
thanks for your answer. I found that the problem is in the topology
Markus Metz pisze:
Margherita Di Leo wrote:
Hi all
Hi Markus,
thanks for your answer. I found that the problem is in the topology
of the river network. I think that v.strahler produces many '0'
because it finds many little 'circles' in the stream vector. I tried
to produce the stream
stephen sefick wrote:
Well, I am not sure what I am going to do. I would look at the code,
but I am not adept at C. Also, I don't know if I understand the
algorithm, but I think if the topology were complete then it would
work OK. I think the 0 orders are unconnected streams- danglers.
re: inline
On Wed, Jul 22, 2009 at 2:01 AM, Markus
Metzmarkus.metz.gisw...@googlemail.com wrote:
stephen sefick wrote:
Well, I am not sure what I am going to do. I would look at the code,
but I am not adept at C. Also, I don't know if I understand the
algorithm, but I think if the
stephen wrote:
Well, I am not sure what I am going to do. I would look at the
code, but I am not adept at C.
none the less, it doesn't hurt to look, depending on how it is written
it might be understandable / tweakable.
MMetz:
What exactly is wrong with topology? The existence of these
I'm sorry but the procedure that I proposed does not produce good
results. In fact the ascii file produced by v.strahler has very strange
orders, and also many 0 (that does not have sense in strahler order!). I
think the problem is generated in finding the outlets and/or confluences.
Waiting
Margherita Di Leo wrote:
I'm sorry but the procedure that I proposed does not produce good
results. In fact the ascii file produced by v.strahler has very
strange orders, and also many 0 (that does not have sense in strahler
order!). I think the problem is generated in finding the outlets
Well, I am not sure what I am going to do. I would look at the code,
but I am not adept at C. Also, I don't know if I understand the
algorithm, but I think if the topology were complete then it would
work OK. I think the 0 orders are unconnected streams- danglers.
This makes sense because they
I'm not sure why there would be disconnected segments in the
accumulation output.
Mark
On Jul 20, 2009, at 3:35 PM, stephen sefick ssef...@gmail.com wrote:
I have a low relief area in the costal plain of georgia that I am
trying to produce a topologically correct stream network. There are
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