[GRASS-user] Evaluation of AW3D30 open access global DEM for flood modelling

[Markus Metz]

On Tue, Sep 19, 2017 at 9:10 PM, Markus Metz <markus.metz.giswork at gmail.com>
wrote:
>
>
>
> On Tue, Sep 19, 2017 at 5:53 PM, Laurent C. <lrntct at gmail.com> wrote:
> >
> > Hello Markus,
> >
> > Thanks for your interest.
> > By SRTM1 we mean the 1 arcsecond version of SRTM. As far as we know, it
comes in only one version.
>
> About USGS SRTM versions, see
> http://dx.doi.org/10.5067/MEaSUREs/SRTM/SRTMGL1.003
> https://dds.cr.usgs.gov/srtm/What_are_these.pdf
> https://dds.cr.usgs.gov/srtm/version2_1/Documentation/SRTM_Topo.pdf
>
> the latter one states that "there is a difference between the data
distributed via ftp from the Land Processes
> Distributed Active Archive Center [now https://dds.cr.usgs.gov/srtm/],
and those available from the EROS Data Center"
>
> I am not sure if this still holds true. Following the EarthExplorer links
> https://lta.cr.usgs.gov/SRTMVF
> https://lta.cr.usgs.gov/SRTM1Arc
>
> it is not clear which versions these are. I guess the non-void filled
version of the EarthExplorer is the subsampled version 2.1, the void filled
version and the global 1 arc sec version are SRTM version 3. Just a guess,
if in doubt, ask USGS.

According to
https://lpdaac.usgs.gov/sites/default/files/public/measures/docs/NASA_SRTM_V3.pdf
and
https://lta.cr.usgs.gov/SRTM1Arc

the USGS EarthExplorer most probably provides NGA version 2, not JPL/NASA
versions 2.1 or 3.

Markus M
>
> > We could make it more clear during the revision.
>
> That would avoid confusion. For example, there is a 1 arc second version
of version 2.1 ;-)
>
> Markus M
>
> >
> > Best,
> > Laurent
> >
> > On 19 Sep 2017 01:49, "Markus Metz" <markus.metz.giswork at gmail.com>
wrote:
> >
> >
> >
> > On Tue, Sep 19, 2017 at 1:41 AM, Laurent C. <lrntct at gmail.com> wrote:
> > >
> > > Hello all,
> > >
> > > Open-access global DEMs like SRTM are a staple in our GIS community.
> > > Last year the JAXA released a new product, the ALOS World 3d 30m
> > > (AW3D30).
> > > Using GRASS and itzï we've carried out an assessment of AW3D30 from
> > > the point of view of flood modelling, and compared it to lidar, SRTM
> > > and ASTER.
> >
> > Very interesting study! I have a question about SRTM: in the paper you
write that you used SRTM version 1, but SRTM version 1 is practically not
used since version 2.1 has been made available. Since 2013, SRTM version 3
has been available:
> >
> > http://dx.doi.org/10.5067/MEaSUREs/SRTM/SRTMGL1.003
> >
> > SRTM version 3 is also the default for r.in.srtm.region.
> >
> > Best,
> >
> > Markus M
> >
> > >
> > > AW3D30 is indeed a very interesting product, and I thought that GRASS
> > > users could be interested in our results:
> > > https://doi.org/10.5281/zenodo.885571
> > >
> > > Best regards,
> > > Laurent
> > > _______________________________________________
> > > grass-user mailing list
> > > grass-user at lists.osgeo.org
> > > https://lists.osgeo.org/mailman/listinfo/grass-user
> >
> >
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