30 arc-second DEM for North America and HawaiiEntry ID: GNVd0191_104
Abstract: 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 arc-second ... DEM project includes generation of 30 arc-second 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 July 1995, North America, Africa, Japan, Madagascar and Haiti are complete and available for distribution. The South American data set is under development, as are Europe and Asia.
The North American 30 arc-second DEM was compiled from various data sources. Elevation data at a 3 arc-second resolution exist for a large portion of the North American continent. The conterminous United
States, Hawaii, Mexico and the Caribbean Islands have complete coverage at 3 arc-second resolution. Most of Alaska and parts of Central America and Canada are also covered by this higher resolution data. Where ever the higher resolution 3 arc-second data were available and distributable, they were generalized to the desired 30
arc- second resolution using a nearest neighbor resampling. (The 3 arc-second data covering the Caribbean, parts of Central America and
Hawaii were received by EDC already resampled to 30 arc-second. The data for Alaska, Canada, the United States and Mexico were resampled at EDC).
The 30 arc-second DEM for the parts of the North American continent lacking 3 arc-second data was derived from the 1:1,000,000 scale Digital Chart of the World (DCW) mapping. The point and contour
hypsography coverages were processed into a 30 arc second DEM using the ANUDEM gridding software. This software utilized the DCW hydrography information along with the hypsography to generate a hydrologically realistic DEM. This technique was used to produce the
30 arc-second DEM in all areas not covered by existing, distributable DEMs, including a large part of Canada and smaller portions of Alaska and Central America. The data generated in this fashion were merged
with the existing resampled data using various mosaicing techniques to minimize the discontinuities between the different data sources.
Data Set Citation
Dataset Originator/Creator: USGS/EROS DATA CENTER
Dataset Title: 30 ARC-SECOND DEM For North America and HawaiiOnline Resource: http://www.grid.unep.ch/data/summary.php?dataid=GNV191&category=lit...
Start Date: 1995-07-01Stop Date: 1995-07-01
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: 1996-11-18
Last DIF Revision Date: 2016-11-18