A USGS DEM can be classified into one of four levels of quality. This is due to the multiple methods of data collection, and certainty in the data.
DEM level DEM series Production process Comments Level 1
7.5-minute
30-minute ...
USGS DEMA digital elevation model produced by the Survey Branch of the United States Department of the Interior, consisting of a regular array of elevations referenced in the Universal Transverse Mercator (UTM) coordinate system.
Set the Input USGS DEM file to the unzipped dem.
Set the Output raster to a grid called M:\NETID.gdb\eatonville.
The USGS DEM is the file that ends in .dem (e.g., 3097420g.dem)
Leave all the defaults as they are for now - we will talk about these in class.
The official USGS DEM format, although destined to become an antique, is still widespread. A lot of GIS software reads some variant of this format directly.
Version 5.0.7g: USGS DEM Support
Version 5.0.6i: New Line Editor Tools
Version 5.0.5e: New Vector Smoothing Functions ...
Using USGS DEMs in ArcView GIS - This brief tutorial walks you through the process of importing USGS SDTS format DEMS in ArcView GIS with the help of the SDTS2DEM translator (Nov. 2001) ...
5 minute USGS DEM's of Voyageurs National Park, which were not native Vistapro files and therefore posed additional challenges.
program is not free, it will read ASTER geotiff data and write USGS DEM
files just like GEOTIF, except probably better. It costs about $150 and is available at . Mike Childs (no relation) will probably be happy to answer questions about that program.
Arc second - A unit of angular measurement that is used to denote the spacing of adjacent profiles in USGS DEMs. An arc second is approximately equivalent to 30 meters of linear measurement.
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In areas where there has been an extensive direct survey and mapping program (most of Europe and the Continental US, for example), the compiled data forms the basis of basic digital elevation datasets such as USGS DEM data.
These include ArcInfo coverages; shapefiles; CAD, VPF, TIFF, JPEG, BMP, SunRaster, USGS DEM, DTM, Department of Defense DTED, generic ASCII, and MrSID files; and ArcGIS themes created from tabular data.
USGS, 1987. Digital Elevation Models, Data Users Guide 5, US Department of the Interior, USGS, Reston, VA. Describes the creation and data structures of USGS DEMs in detail.
DISCUSSION AND EXAMINATION QUESTIONS ...
Oracle Spatial GeoRaster
GeoTiff (*.tif)
Tag Image File (*.tif)
Internet Tiff (*.itiff)
Internet Tiff 64 bit (*.iTiff64)
SPOT Digital Image Map (*.dim)
USGS DEM ASCII (*.dem)
USGS SDTS DEM (*.catd.DDF) ...
 See also: USGS, DEM, GIS, Information, Digital
  
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