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Problems SRTM data

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  • Jonathan
    If you find any compatibility problems with the data at http://rmw.recordist.com then please tell me and I will advise thir author. But they work OK for me.
    Message 1 of 6 , Apr 25, 2010
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      If you find any compatibility problems with the data at http://rmw.recordist.com then please tell me and I will advise thir author. But they work OK for me.

      > MANY independent researchers in disparate fields must by now be > upset
      > about the voids, and other problems/errors, in SRTM.

      When SRTM data were first published they were a major breakthrough in that they provided good quality and freely available 3" DEM data for more than 80% of the world, including many areas previously restricted by, or only available at prohibitive prices from, national surveys, and many tropical areas which had never been properly mapped by anyone.

      The main problem was high latitude areas, which were not covered by SRTM but which are now covered completely by http://viewfinderpanoramas.org/dem3.html, apart from North America which are covered by USGS and CDED. The recordist site has reproduced these with my permission.

      The other problem was the SRTM voids, which do not affect most places but which do affect some mountain and desert areas, and a few parts of North America which were missed by the flightpaths. I have filled most mountain and some desert areas, but there are still some outstanding. I am currently working on Patagonia. Despite its anomalies and artifacts ASTER GDEM is helping me to fill some of these; for example there are parts of north and east Patagonia with large SRTM voids but which GDEM has made quite well. I am catching and deleting the SRTM phase errors as I spot them.

      Jonathan


      --- In prominence@yahoogroups.com, "Adam Helman" <helman@...> wrote:
      >
      > Thanks, Jonathan.
      >
      > If the site
      >
      > http://rmw.recordist.com
      >
      > truly employs the **identical** SRTM formatting, then that data must also be
      > Winprom-compatible - and THAT would be convenient.
      >
      > MANY independent researchers in disparate fields must by now be upset
      > about the voids, and other problems/errors, in SRTM.
      >
      > Sincerely,
      > Adam
      >
      >
      >
      > ----- Original Message -----
      > From: Jonathan
      > To: prominence@yahoogroups.com
      > Sent: Saturday, April 24, 2010 2:14 AM
      > Subject: [prominence] Re: Chihuahua prom point and THE MONSTER VOID
      >
      >
      >
      > Adam,
      >
      > I am fairly sure that these SRTM monster void areas were missed by the SRTM flight bands. That would explain their diamond shapes.
      >
      > There are better data sources for prominence research in North America, with or without the monster voids. They are from NED, CDED and INEGI and have been made freely available. Besides being complete, these data are also ground based, unlike SRTM which can be distorted by vegetation and buildings. Data mainly from these sources are provided in SRTM format at http://rmw.recordist.com/. I think there may be some input from SRTM here, especially in Canada, but the voids are filled. The main problem with these data is where SRTM data have been used where available. SRTM phase unwrapping error areas have not been deleted, creating local artifacts.
      >
      > Jonathan
      >
      >
      >
      >
      >
      >
      >
      >
      > [Non-text portions of this message have been removed]
      >
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