-------- Original Message --------
Subject: FW: 'Most Complete Earth Map Published'
Date: Wed, 1 Jul 2009 09:00:06 -0500
From: Doug Behm <[log in to unmask]>
To: <[log in to unmask]>
*From:* Joseph Kerski [mailto:[log in to unmask]]
======================================================
Douglas D. Behm, P.G. [log in to unmask]
<mailto:[log in to unmask]>
University Geologist
Office of Land Management and Real Estate Services
University of Alabama
Yes, yesterday I was tinkering with that very same data set. NASA and
Japan released a new digital topographic map of Earth Monday that covers
more of the Earth than ever before. The map was produced with detailed
measurements from NASA's Terra spacecraft. The new global digital
elevation model of Earth was created from nearly 1.3 million individual
stereo-pair images collected by the Japanese Advanced Spaceborne Thermal
Emission and Reflection Radiometer, or ASTER, instrument aboard Terra.
NASA and Japan's Ministry of Economy, Trade and Industry (METI),
developed the data set. It is available online to users everywhere at no
cost. This is a 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.
Bottom line: We are no longer limited to 90meter SRTM data for the
globe - we now have ready access to 30meter! However, use caution
because according to the developer, whom I know at EDC in Sioux Falls,
there are some edge and other issues, and just like with any data set,
the data user needs to be aware of these issues before using the data.
Article in GIM magazine today about this:
http://www.gim-international.com/news/id3889-Most_Complete_Topographic_Map_of_Earth.html
ASTER GDEM tiles may be downloaded electronically from ERSDAC by
visiting http://www.gdem.aster.ersdac.or.jp/
and from the LP DAAC by visiting
https://wist.echo.nasa.gov/~wist/api/imswelcome/
<https://wist.echo.nasa.gov/%7Ewist/api/imswelcome/>. I tried to use
the site in Japan because it had a nice map interface, but eventually I
abandoned it and went with:
https://wist.echo.nasa.gov/wist-bin/api/ims.cgi?mode=MAINSRCH&JS=1
<https://wist.echo.nasa.gov/wist-bin/api/ims.cgi?mode=MAINSRCH&JS=1>
I had to register on the site, and then navigate to the data. After I
ordered a block of data from 39.5 to 40 North Latitude, 105 to 105.5
West Longitude, a short time later I received an email indicating that
the data was ready.
I received 4 ZIP files that unpacked into 8 TIF files, 4 of which were
the actual data, which I loaded into ArcGIS. A screen shot of my
results is here:
http://cid-e9eb9732b3340dd9.skydrive.live.com/self.aspx/.Public/denver%7C_asterdem%7C_screenshot.jpg
Warning: This is the kind of site that is in desperate need of someone
writing some clear user instructions. Even the registration information
was painful. Until those instructions are written, if you are willing
to stick with it, then riches of spatial data joy await you.
Joseph Kerski
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Joseph J. Kerski, Ph.D
Education Manager
Environmental Systems Research Institute, Inc.- ESRI
1 International Court
Broomfield CO 80021-3200 USA
E: [log in to unmask] <mailto:[log in to unmask]>
V: 303-449-7779 x 8237
F: 303-449-8830
Participate in the ESRI Education Community:
http://edcommunity.esri.com
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