digital elevation model - This term is used very generally to describe a great variety of terrain files and file formats There are also a number of mutually incompatible file formats that use the dem file name extension
DEM means "Digital Elevation Model" It is a "grid" of points (usually on an even spacing) that contains both horizontal and vertical data about the earth's surface DEMs are commonly used for the creation of "ortho" photos A sketch of a DEM is shown below
Digital Elevation Model data DEMs are continuous raster layers in which data file values represent elevation DEMs are available from the USGS at 1: 24,000 and 1: 250,000 scale, can be produced with terrain analysis programs, and IMAGINE OrthoMAX
Digital Elevation Model A digital representation of a continuous variable over a two-dimensional surface by a regular array of z values referenced to a common datum Digital elevation models are typically used to represent terrain relief The format of the USGS digital elevation data sets
Digital Elevation Model : A model of terrain relief in the form of a MATRIX Easch element of the DEM is regared as a node of an imaginary grid The gird is defined by identifying one of its corner (lower left usually), the distance between nodes in both the X and Y directions, the number of nodes in both the X and Y directions and the gird orientation