30 arc-second DEM for AsiaEntry ID: GNVd0182_104
Abstract: PLEASE NOTE: This is a preliminary release of the Asian 30 arcsecond DEM. Constructive comments from users of this data set are greatly appreciated. Please contact Kris Verdin (email@example.com) or Sue Jenson (firstname.lastname@example.org) with your comments.
Data Set Assembly
A Digital Elevation Model (DEM) consists of a sampled array of elevations for ground positions that are ... normally spaced at regular intervals. The EROS Data Center's (EDC) 30 arcsecond DEM project includes generation of 30 arcsecond DEM data for the entire world. These data are being made available to the public via anonymous ftp as they become available. As major geographic regions are completed, the data, along with various derivative data sets, will be published on CD-ROM. As of December 1995, Asia, Europe, North America, and Africa are complete and available for distribution. The South American data set is under development, as are Australia, Antarctica and Indonesia.
The Asian 30 arcsecond DEM was compiled from several data sources. The primary source was a generalization of the Level 1 Digital Terrain Elevation Data. Digital Terrain Elevation Data (DTED) is a 1 degree by 1 degree dataset produced by the US Defense Mapping Agency (DMA) that contains digital data in the form of a uniform matrix of terrain elevation values for most parts of the world. It was originally designed to provide basic quantitative data for military training, planning and operating systems that require terrain elevation, slope and related information. This includes applications such as modeling the influence of terrain on radar line-of-sight, automatic height determination, terrain modeling etc.
The EROS Data Center's Digital Elevation Modeling project, that includes generation of 30 arc second data for the entire world, employed the DTED-Level 1 data in developing a 30 arc second DEM of Asia. The DTED data cover over 90% of the landmass of Asia. The elevation data for the areas of Asia which are not covered by the DTED data were developed using the 1:1,000,000 scale Digital Chart of the World (DCW) mapping.
The point and contour hypsography coverages were processed into a 30 arcsecond DEM using the ANUDEM gridding software. This software utilitized the DCW hydrography information along with the hypsograpy to generate a hydrologically realistic DEM. This technique was used to produce the 30 arcsecond DEM in all areas not covered by existing, distributable DEMs.
The data generated in this fashion were merged with the existing resampled data using various mosaicing techniques to minimize the discontinuities between the data sources.
Spatial extent of coverage
The 30 arcsecond Asian DEM complements the previously released 30 arcsecond DEM of Europe to provide 30 arcsecond cover of the entire Eurasian landmass. The largest part of the Asian DEM extends from 70E to 180E longitude and 0N to 85N latitude. A small portion covering the Chukchi Peninsula which extends across the international date line extends from 180W to 168W longitude and 56N to 72N latitude. To fill out the Eurasian continent, additional coverage extending from the Middle East to India extends from 32E to 70E longitude and 12N to 35N latitude.
For more details, see http://www.grid.unep.ch/data/summary.php?dataid=GNV182
Data Set Citation
Dataset Originator/Creator: USGS/EROS DATA CENTER
Dataset Title: 30 ARC-SECOND DEM For AsiaOnline Resource: http://www.grid.unep.ch/data/summary.php?dataid=GNV182&category=lit...
Start Date: 1996-12-01Stop Date: 1996-12-01
Access Constraints Public
Role: TECHNICAL CONTACT
Phone: (+254-20) 7624214
Fax: (+254-20) 7624315
Email: Johannes.Akiwumi at unep.org
Head, Data and Information Management Section Division of Early Warning and Assessment (DEWA) United Nations Environment Programme P. O. Box 30552
Postal Code: 00100
Extended Metadata Properties
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Creation and Review Dates
DIF Creation Date: 1996-12-12
Last DIF Revision Date: 2017-08-23