On Thu, Sep 21, 2017 at 7:47 PM, Laurent C. <lrn...@gmail.com> wrote: > > 2017-09-20 4:07 GMT-05:00 Markus Metz <markus.metz.gisw...@gmail.com>: > > > > > > On Tue, Sep 19, 2017 at 9:10 PM, Markus Metz < markus.metz.gisw...@gmail.com> > > wrote: > >> > >> > >> > >> On Tue, Sep 19, 2017 at 5:53 PM, Laurent C. <lrn...@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, > > The JPL webpage about SRTM links to the USGS EROS website for > download, which itself links to Earthexplorer: > https://www2.jpl.nasa.gov/srtm/cbanddataproducts.html
The JPL/NASA website also links to http://dds.cr.usgs.gov/srtm/ where you get the JPL/NASA SRTM products version 1 and 2.1 JPL/NASA SRTM version 3 (completely void-filled version 2.1) is available at https://lpdaac.usgs.gov/dataset_discovery/measures/measures_products_table JPL/NASA version 3 with 1 arc second resolution is described at https://lpdaac.usgs.gov/dataset_discovery/measures/measures_products_table/srtmgl1_v003 JPL/NASA version 3 with 3 arc seconds resolution is described at https://lpdaac.usgs.gov/dataset_discovery/measures/measures_products_table/srtmgl3_v003 Personally, I would prefer SRTM JPL/NASA version 3 over any other SRTM version, mainly because according to the documentation it supersedes the NGA version 2 available through the USGS EartExplorer. Markus M > https://eros.usgs.gov/elevation-products > > Do you know if there is a more recent version of the 1 arcsec product, > and where to find it? > > Best, > Laurent > > > > > 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.gisw...@gmail.com> > >> > wrote: > >> > > >> > > >> > > >> > On Tue, Sep 19, 2017 at 1:41 AM, Laurent C. <lrn...@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@lists.osgeo.org > >> > > https://lists.osgeo.org/mailman/listinfo/grass-user > >> > > >> > > >
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