Replying to [comment:1 hellik]:
> Replying to [ticket:2516 madi]:
>
> >
> > elev2stream map has several null values.
>
> where are the null values?
>
> I know only the null values at the border of the DEM (red in the
screenshot) where no stream information is available.
Hi, in my case null values are scattered all over the map, see attached
screenshot (the large spots however are water). I realised that the
command line i actually gave is slightly different from the one i posted
earlier (if matters) and is:
Replying to [comment:2 madi]:
> Replying to [comment:1 hellik]:
> > Replying to [ticket:2516 madi]:
> >
> > >
> > > elev2stream map has several null values.
> >
> > where are the null values?
> >
> > I know only the null values at the border of the DEM (red in the
screenshot) where no stream information is available.
>
> Hi, in my case null values are scattered all over the map, see attached
screenshot (the large spots however are water). I realised that the
command line i actually gave is slightly different from the one i posted
earlier (if matters) and is:
>
> r.stream.distance --verbose stream_rast=stream1500 direction=drainage
elevation=dem method=downstream distance=dist2stream_2
difference=elev2stream_2 memory=2000
>
> Thanks
> madi
some tests with a DEM subset:
{{{
- maybe differences in the r.stream.*-modules between all-in-memory and
swapped memory mode; in my tests I can't see any difference
- I've done a r.geomorphon run on the DEM; it seems the DEM is very
heterogenous. may be these null values are DEM artefacts?
- I've done a r.neighbor size=3 and size=5 on the DEM; there seems to be a
less number of null values. maybe this indicates DEM artefacts?
- I've done a r.stream.distance run with r.stream.extract-outputs (streams
and flowdir) instead; there are some differences regarding null values
between using r.watershed or r.stream.extract-output as r.stream.distance
input
}}}