Global Land Survey Digital Elevation Model (GLSDEM)Entry ID: GLCF_glsdem
Abstract: The Global Land Survey Digital Elevation Model (GLSDEM) is a spatial data collection crucial to new global imagery products from NASA and the USGS. In the late 1990s, the U.S. Congress set aside funding to stimulate the use of remotely sensed imagery and products through the Science Data Purchase (SDP) program. One of the SDP collections is GeoCover - a coordinated dataset of orthorectified ... Landsat imagery available in three epochs. The GeoCover collection was orthorectified using classified control points and the GTOPO30 global elevation model. Since it first became available, the GeoCover collection was and still is a big success, encouraging use of remotely sensed imagery for Earth science research around the world, and bridging the use of imagery into myriad other uses. The geodetic accuracy of the input elevation model, however, was less than ideal so that some GeoCover scenes suffered from poor geo-registration.
With the advent of higher precision DEMs for the entire planet, the Landsat images used to make the GeoCover collection were reprocessed for higher geo-locational quality into the Global Land Survey (GLS) collection. The GLS collection contains the same three epochs as in GeoCover - 2000, 1990, 1975 - plus a fourth epoch focused on 2005. The GLS2005 collection includes imagery from the TM, ETM+ and ALI sensors. The GLS collection was made possible by the development of more accurate elevation models with global or regional coverage, including the National Elevation Dataset (NED) of the USA, the Canadian Digital Elevation Dataset (CDED) of Canada and the Shuttle Radar Topography Mission (SRTM) covering most of the globe. In order to orthorectify the GLS scenes, the elevation data was coordinated into the GLSDEM product. The GLSDEM product is of 3 arc second (90m) resolution and in Geographic coordinates with a WGS-84 datum. GLCF produces GLSDEM files in WRS-2 tiles in the GeoTIFF format, UTM projection and horizontal WGS 84 datum of the corresponding GLS datasets. For each path/row, the original USGS Degree tiles are mosaicked and subset with a 9km buffer to reproduce the GLSDEMs into the Landsat WRS-2 tiling system. The GLSDEM degree tiles may be obtained from EROS Data Center, USGS or the GLCF. The WRS-2 edition of the GLSDEMs is available only through the GLCF.
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Data Set Citation
Dataset Originator/Creator: USGS
Dataset Title: Global Land Survey Digital Elevation Model (GLSDEM)
Dataset Release Place: College Park, Maryland
Dataset Publisher: Global Land Cover Facility, University of MarylandOnline Resource: http://glcf.umiacs.umd.edu/data/glsdem/index.shtml
Latitude Resolution: 90 m
Longitude Resolution: 90 m
Horizontal Resolution Range: 30 meters - < 100 meters
ISO Topic Category
Use Constraints Use is free to all; effectively held by USGS & NASA. The ultimate copyright and ownership of the product, however, is held by the citizens of the United States of America, the Republic of Germany, and the Dominion of Canada.
As a courtesy, please credit the Global Land Cover Facility (GLCF) as the source for this data set in some manner. Our suggestion: Source for this data set was the Global Land Cover Facility, www.landcover.org.
Data Set Progress
Distribution Media: Online FTP
Fees: No fees
Role: TECHNICAL CONTACT
Email: glcf at umd.edu
Global Land Cover Facility 3166 A.V. Williams Bldg University of Maryland
City: College Park
Province or State: MD
Postal Code: 20742
Role: DIF AUTHOR
Phone: (301) 614-6898
Email: Tyler.B.Stevens at nasa.gov
NASA Goddard Space Flight Center Global Change Master Directory
Province or State: MD
Postal Code: 20771
Creation and Review Dates
DIF Creation Date: 2011-02-03
Last DIF Revision Date: 2011-02-04