USGS Digital elevation Models (DEM)
> The DEM FAQ
The USGS Digital Elevation Model (DEM) data files are digital representations of cartographic information in a raster form. DEMs consist of a sampled
array of elevations for a number of ground positions at regularly spaced intervals. These digital cartographic/geographic data files are produced by the
U.S. Geological Survey (USGS) as part of the National Mapping Program and are sold in 7.5-minute, 15-minute, 2-arc-second (also known as
30-minute), and 1-degree units. The 7.5- and 15-minute DEMs are included in the large scale category while 2-arc-second DEMs fall within the
intermediate scale category and 1-degree DEMs fall within the small scale category - (Source: USGS)
NOTICE OF UPDATE TO USERS OF USGS SDTS DEMS (Oct. 14, 2001)
NOTICE TO USERS OF USGS SDTS DEMS
OUTLINE OF CHANGES IN DEM DATA FORMAT
Join the USGS Hosted SDTS Mailing List
Why won't DEMs open in ArcView GIS? - Please note, USGS DEM data updated last year (2001) may not import correctly using the import utility that comes with ArcView GIS (or other programs). Unless the software you are using supports the new SDTS header format you will have to run the SDTS2DEM utility on the data - See http://www.gisdatadepot.com/dem/sdts2dem.html
GeoCommunity DEM Resources
The USGS DEM Standards (PDF)
VDatum Transformation Tool - VDatum is a tool for the transformation of elevation data from one vertical datum into another. This document is part of the "Tampa Bay Bathy/Topo/Shoreline Demonstration Project" - if you
are involved in hydrographic and/or bathymetric mapping and working with DEM and topopgraphic
data we encourage you to learn more by visiting the Tampa Bay Shoreline project website. (April 26, 2002)
Extracting DEMs from Topographic Maps - Few people realize that the shaded relief maps appearing on the front pages of our national publications were not produced from satellite data because that data is classified. Instead, they were derived from the most primitive but reliable source of DEM data that we have: paper topographic maps. More on this from John Childs.
(Dec. 28, 2001)
Using USGS DEMs in ArcView GIS - As GIS technology goes mainstream, we at the GeoCommunity have found a dramatic increase in the number of people downloading freely available data only to then be stumped when it comes to actually viewing or using the data. Data that is particularly troublesome for users is USGS SDTS formatted data. This article briefly examines how users can easily download USGS DEMS and use them in ArcView GIS. (Nov. 26, 2001)
IKONOS DEM Overlays - The author demonstrates how one can easily use free ortho rectified, aligned and georeferenced satellite imagery along with free data from the gisdatadepot and create stunning 3D imagery. This is all easily done using 3DEM. (Oct. 15, 2001)
Announcements and News regarding New Data Distribution Methods and Data Format Issues
If you believe there may be a problem with an individual data set or if you
need additional information about SDTS, please access the SDTS web site at
http://mcmcweb.er.usgs.gov/sdts/ or send email to firstname.lastname@example.org.
- NOTICE OF UPDATE TO USERS OF USGS SDTS DEMS (Oct. 14, 2001)
- SDTS News Announcements from the USGSAttention Software Developers and Vendors Supporting SDTS Raster Profile (Aug, 29, 2001)
- SDTS News Announcements from the USGSDetails Here (Aug, 14, 2001)
- Message to the SDTS list from USGS representative explaining the reasons for making DEM data available from the GISDataDepot Details Here (Aug, 08, 2001)
- Message from GeoComm Editor to the GISList regarding DEMs Details Here (Aug, 03, 2001)
The new STDS DEM data can be used by ArcView3.2 but requires editing of the xxxxIDEN.DDF file - this posting to the discussion board provides details. (Aug, 03, 2001)
- Outline of changes in DEM data format (Aug, 02, 2001)
Did you Know that USGS DEM data pre 2001 has positional errors
FYI - SDTS DEMs created before January 1, 2001 may contain up to 30-meter horizontal error. The error may affect user applications where
absolute positional accuracy or tile-to-tile relative accuracy is critical. These errors were generated during the conversion from USGS native DEM
format to the SDTS DEM format. Native format DEMs do not contain these positional errors. The USGS is presently considering the further
actions to be taken regarding these errors. For details regarding the two types of errors refer to SDTS DEM Positional Error.
The GeoCommunity is pleased to announce that corrected DEM data is now available for free download and/or purchase
from The GeoCommunity & GISDataDepot portals. We have worked closely with the USGS to make this data available to The GIS
Other Suggested DEM Resources
Mt. Rainier Challenge: Superior Overlays using 3DEM - John Childs briefs The GeoCommunity on how you can easily create stunning 3D output using low-cost software and free data from The GISDataDepot.com(Aug. 27, 2001)
USGS Digital Elevation Model Data - A guide to DEMs from the USGS.
USGS GNIS - The Geographic Names Information System (GNIS), developed by the USGS in cooperation with the U.S. Board on Geographic Names (BGN), contains information about almost 2 million physical and cultural geographic features in the United States. The Federally recognized name of each feature described in the data base is identified, and references are made to a feature's location by State, county, and geographic coordinates. The GNIS is our Nation's
official repository of domestic geographic names information.
USGS Quad Grid MapFinder - Having problems finding determining which quad sheet you need? Try this very handy USGS Quad grid (PDF format) supplied by our friends at USGSQuads.
SDTS News Updates - The USGS provides regular updates and useful resources to help
you work with SDTS data.
Converting STDS DEMs for use in WCS, by R Scott Cherba - A tutorial and downloads offered up
by the makers of the World Construction Set.
ArcUser - Article "Converting and Using SDTS DEM Data". This article tells how to locate, download, and process
1:24,000-scale digital elevation model (DEM) data in Spatial
Data Transfer Standard (SDTS) format.
ArcUser - Article "Using 1:250,000 Scale DEM Data.
This article describes how to download,
import, reproject, and merge 1:250,000-scale digital elevation
model (DEM) data
USGS DEM Status Graphics
dlgv32 Pro Viewer - Windows 95/NT software for viewing a variety of digital cartographic data. It was originally developed in support of USGS digital line graph (DLG) production activities
If you develop DEM related products, scripts, extensions, or translators and would like to make them available to the public,
please send e-mail to email@example.com
Prior to downloading or purchasing data, please take a moment to view the
Terms and Conditions of Use