On Tue, Sep 19, 2017 at 9:10 PM, Markus Metz <[email protected]> wrote: > > > > On Tue, Sep 19, 2017 at 5:53 PM, Laurent C. <[email protected]> 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" <[email protected]> wrote: > > > > > > > > On Tue, Sep 19, 2017 at 1:41 AM, Laurent C. <[email protected]> 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 > > > [email protected] > > > https://lists.osgeo.org/mailman/listinfo/grass-user > > > >
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