METI and NASA Release Version 2 ASTER Global DEM
The version 2 collection of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation Model (GDEM) was released jointly October 17, 2011 by the Ministry of Economy, Trade, and Industry (METI) of Japan and the United States National Aeronautics and Space Administration (NASA). As with Version 1, METI and NASA are contributing the ASTER GDEM to the Global Earth Observation System of Systems (GEOSS). Consequently, the ASTER GDEM is available at no charge to users worldwide via electronic download from the Earth Remote Sensing Data Analysis Center (ERSDAC) of Japan and from NASA’s Land Processes Distributed Active Archive Center (LP DAAC).
ASTER Global DEM
ASTER, on the NASA spacecraft Terra, is capable of collecting in-track stereo using nadir- and aft- looking near infrared cameras. Since 2001, these stereo pairs have been used to produce single-scene digital elevation models (DEM). The best quality data from the DEM record were compiled globally to generate the ASTER GDEM 2.
Version 2 is produced with the same gridding and tile structure as Version 1. Extensive validation of GDEM 2 noted substantial improvements in product quality due specifically to the increased number of acquired ASTER stereo pairs and refinements to the production algorithm (water masking, smaller correlation kernel size, bias removal). These improvements include increased horizontal and vertical accuracy, better horizontal resolution, reduced presence of artifacts, and more realistic values over water bodies.
Users are nonetheless advised that the products still may contain anomalies and artifacts that will reduce its usability for certain applications. The data are provided “as is” and neither NASA nor METI/ERSDAC will be responsible for any damages resulting from use of the data.
ASTER GDEM 2 is subject to user acknowledgment of redistribution and citation policies required by METI and NASA. Product tiles may be downloaded electronically from ERSDAC and from the LP DAAC by visiting:
For more information, contact LP DAAC User Services
Deadline for Submitting Abstracts extended to May 27
William T. Pecora Memorial Remote Sensing Symposium
Pecora 18 “Forty Years of Earth Observations: Understanding a Changing World”
The theme for Pecora 18 is: "Forty Years of Earth Observations: Understanding a Changing World." The symposium focuses on how 40 years of Landsat and other Earth observation missions have influenced our understanding of the changing Earth, and contributed to improving information needed for managing our natural resources. Special emphasis will be given to the current state of the Landsat program such as the free data revolution and the upcoming launch of the Landsat Data Continuity Mission. Lessons from the past and present serve as the foundation for looking toward the next generation of operational land remote sensing.
The Pecora 18 Symposium will be held Monday through Thursday, November 14 to 17, 2011 at the Washington Dulles Hilton in Herndon, Virginia.
The deadline for submitting abstracts for Pecora 18: "Forty Years of Earth Observations: Understanding a Changing World" has been extended to May 27, 2011. Symposium topics are:
- Achieving William Pecora’s Vision
- Highlights from the Past Four Decades
- Science and Applications in an Era of Free Landsat Data
- Mapping and Monitoring the Earth
- The Next Forty Years
Abstracts should be submitted electronically using the form available at the symposium web site, (http://pecora.asprs.org/). Authors will be asked to select a category for their paper according to the categories and topic areas listed on the web site, and they will be asked to state a preference for oral or poster presentation. Abstracts may not exceed 300 words in length. Abstracts also should include 3-5 keys words and contact information for the senior author and the presenter.
If electronic submission using the web site is not possible, abstracts and required information may be mailed to the Pecora 18 Steering Committee Chairman, Mr. Tom Holm, U.S. Geological Survey, EROS Center, Sioux Falls, SD 57198 or emailed to email@example.com.
All abstracts will be evaluated by no fewer than three technical reviewers, and selections will be based on overall quality of the abstract and its responsiveness to the symposium theme. Abstracts are due May 27, 2011. Upon notification of acceptance, authors will be expected to sign and return the acceptance letter verifying their intent to attend and make a presentation at the symposium.
Papers accepted for oral presentation will be assigned to a concurrent session based on topic. Authors sharing common interests are encouraged to coordinate submission of papers that could form a session on a specific topic. Concurrent sessions will be 90 minutes in duration, consisting of three or four oral presentations, each of which will be 15-20 minutes in length.
ASTER GDEM Explorer (DEMEX) now available at the LP DAAC
The Land Processes Distributed Active Archive Center (LP DAAC) announces the release of the ASTER Global Digital Elevation Model (GDEM) Explorer tool (DEMEX). This tool can be used to browse and download ASTER GDEM data based on geographic areas of interest or predefined regions, including state, province, and county (for the United States). Data output from DEMEX is available in GeoTIFF or ArcASCII format. DEMEX is the result of collaboration between the LP DAAC and George Mason University's Center for Spatial Information Science and Systems.
ASTER Global DEM (GDEM) data are subject to redistribution and citation policies. Users of DEMEX are required to have an ECHO/WIST account to download data. Register for an ECHO/WIST account by clickinghere, and selecting "Enter WIST", then "Create Account". Contact LP DAAC User Services for additional information.
New EarthExplorer Client
A beta version of the new EarthExplorer client is now available with limited capability to search and download data. The first data are the Landsat Global Land Survey (GLS) datasets. This new EarthExplorer client includes enhanced user capabilities and will eventually replace the current version once all the available data sets have been transitioned. There will be periodic releases of datasets and functionality over the next several months. In the mean time, both versions of EarthExplorer will be maintained and available until the transition is completed. For further information, go to http://earthexplorer.usgs.gov/, or directly to New EarthExplorer at http://earthexplorer.usgs.gov/.
Explore Significant Topographic Surface Changes in the United States
The U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center Topographic Science team has developed a Web site that provides a wealth of data about topographic change across the United States. The USGS National Inventory of Significant Topographic Changes is available at http://topochange.cr.usgs.gov. The inventory is based on seamless multitemporal elevation data and land cover data. The need for more comprehensive information on the nature and extent of recent human geomorphic activity led to a spatial emphasis for the first ever accounting of topographic change across the United States.
Access the USGS National Inventory of Significant Topographic Changes (http://topochange.cr.usgs.gov)
Emergency Operations Portal
Explore critical pre- and post-disaster images and datasets online for immediate viewing and downloading. The U.S. Geological Survey (USGS) Emergency Operations, in support of the Department of Homeland Security, provides these images for use in disaster preparations, rescue and relief operations, damage assessments, and reconstruction efforts. We supply satellite and aerial images for analysis of disaster areas before, during, and after a disaster.
Access the Emergency Operations Portal (http://hdds.usgs.gov/)