---------- Forwarded message ---------- From: Hannes Reuter <[email protected]> Date: Mon, Jun 29, 2009 at 13:01 Subject: GMorph> ASTER GDEM is out To: [email protected]
Dear geomorphometry people, some really really good news today: NASA/METI released today the 30m global (83degreesNS, ~22600 scenes) ASTER GDEM based on 1,264,118 single ASTER dems from 1.4 million scenes in total. 95% vertical ci: 20 meters, 95% horizontal ci: 30 meters) see http://www.gdem.aster.ersdac.or.jp/ congratulations to NASA/METI to provide the worldwide community with such a long awaited dataset. just a short additional note: >> from website Initial studies to validate and characterize the ASTER GDEM confirm that pre-production accuracy estimates are generally achieved for most of the global land surface, although results do vary and true accuracies do not meet pre-production estimates for some areas. In addition, Version 1 of the ASTER GDEM does contain certain residual anomalies and artifacts that affect the accuracy of the product and may be impediments to effective utilization for certain applications. Consequently, METI and NASA acknowledge that Version 1 of the ASTER GDEM should be viewed as “experimental” or “research grade.” Nevertheless, they are confident that the ASTER GDEM represents an important contribution to the global earth observation community. << the link to the evaluation report will be probably be published today/the coming days. as i/we had the possibility to evaluate 5 tiles beforehand - from our analysis i/we can tell that you will run into some of the following: step anomalies across mosaicing edges, mole runs, sinks (we observed some down to 180m below the surrounding), artifical mountains (up to 200m) noise non existing water mask in case only a couple of images n<4 have been used also the horizontal accuracy has some interesting features sometimes... which certanly might or might not influence the calculation of your terrain parameters. i know you all can derive your own conclusions. all depends on your tile ... ;-) data can be downloaded from JAPAN/METI at http://www.gdem.aster.ersdac.or.jp/ or LP DAAC -> https://wist.echo.nasa.gov/~wist/api/imswelcome/. restrictions of 100 tiles apply and only 16 connections at the same time are allowed.....so you might have to wait a bit. cheers hannes... __._,_.___ Messages in this topic (1) Reply (via web post) | Start a new topic Messages | Photos | Links | Polls | Members | Calendar Post message: [email protected] Subscribe: [email protected] UNSubscribe: [email protected] Homepage: http://www.egroups.com/group/geomorphometry Change settings via the Web (Yahoo! ID required) Change settings via email: Switch delivery to Daily Digest | Switch format to Traditional Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe Recent Activity 1 New Members Visit Your Group Give Back Yahoo! for Good Get inspired by a good cause. Y! Toolbar Get it Free! easy 1-click access to your groups. Yahoo! Groups Start a group in 3 easy steps. Connect with others. . __,_._,___ -- Carlos Henrique Grohmann - Geologist D.Sc. a.k.a. Guano - Linux User #89721 ResearcherID: A-9030-2008 http://continentalcrust.blogspot.com http://www.igc.usp.br/pessoais/guano _________________ Can’t stop the signal. _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
