found: Work cat.: Chirico, P. Void-filled SRTM digital elevation model of Afghanistan [ER], 2005.
found: Messerich, J.A. Digital elevation models of the pre-eruption 2000 crater and 2004-07 dome-building eruption at Mount St. Helens, Washington, USA, 2008:abstr. (Presented in this report are 27 digital elevation model (DEM) datasets for the crater area of Mount St. Helens; DEMs)
found: Geological Survey (U.S.). Washington DEMs [ER], 1999("10-meter DEMs of Western Washington from USGS Jan, 1999 production (lots 1 and 2)"; public domain data from USGS that has been processed for the University of Washington Map Library)
found: Wikipedia, Aug. 31, 2011:Digital elevation model (A digital elevation model is a digital model or 3-D representation of a terrain's surface--commonly for a planet (including Earth), moon, or asteroid--created from terrain elevation data. There is no common usage of the terms digital elevation model (DEM), digital terrain model (DTM) and digital surface model (DSM) in scientific literature. In the most cases the term digital surface model represents the earth's surface and includes all objects on it. In contrast to a DSM, the digital terrain model represents the bare ground surface without any objects like plants and buildings. The term Digital Elevation Model is often used as a generic term for DSMs and DTMs, only representing height information without any further definition about the surface. Other definitions equalise the terms DEM and DTM, or define the DEM as a subset of the DTM, which is also representing other morphological elements. There are also definitions which equalise the terms DEM and DSM. A DEM can be represented as a raster (a grid of squares, also known as a heightmap when representing elevation) or as a triangular irregular network (TIN). The TIN DEM dataset is also referred as a primary (measured) DEM, whereas the Raster DEM is referred as a secondary (computed) DEM. DEMs are commonly built using remote sensing techniques, but they may also be built from land surveying. DEMs are used often in geographic information systems, and are the most common basis for digitally-produced relief maps. The DEM could be acquired through techniques such as photogrammetry, LiDAR, IfSAR, land surveying, etc.)
found: USGS digital elevation model information, via WWW, Aug. 31, 2011(A digital elevation model (DEM) is a digital file consisting of terrain elevations for ground positions at regularly spaced horizontal intervals. The USGS produces five different digital elevation products. Although all are identical in the manner the data are structured, each varies in sampling interval, geographic reference system, areas of coverage, and accuracy; with the primary differing characteristic being the spacing, or sampling interval, of the data. Over the years, the USGS has collected digital elevation data using a number of production strategies including manual profiling from photogrammetric stereomodels; stereomodel digitizing of contours; digitizing topographic map contour plates; converting hypsographic and hydrographic tagged vector files; and performing autocorrelation via automated photogrammetric systems. Of these techniques, the derivation of DEM's from vector hypsographic and hydrographic data produces the most accurate model, and is the preferred method.)
found: Digital elevation model (DEM), via USGS Lake Tahoe Data Clearinghouse website, Aug. 31, 2011(A Digital Elevation Model (DEM) is a digital cartographic/geographic dataset of elevations in xyz coordinates. The terrain elevations for ground positions are sampled at regularly spaced horizontal intervals. DEMs are derived from hypsographic data (contour lines) and/or photogrammetric methods using USGS 7.5-minute, 15-minute, 2-arc-second (30- by 60-minute), and 1-degree (1:250,000-scale) topographic quadrangle maps.)
found: Digital elevation model (DEM) discovery portal, via National Geophysical Data Center website, Aug. 31, 2011(geospatial online catalog that links to web-published digital elevation models (DEMs); DEMs may be bathymetric, topographic, or a merged combination of both. They also range from high-resolution coastal DEMs for local studies to coarser DEMs with global coverage)
