Digital Elevation Model (DEM) and Digital Elevation Data (DED)

Digital Elevation Model (DEM) constructed from Digital Elevation Data (DED). DED is a set of digital data that has a height information of the surface of the earth. DED is commonly used in the analysis of the topography for the purposes of engineering, planning, military, etc.. In engineering for example be used to calculate cut and fill in road construction, or in the field of hydrology is used for flood analysis, manufacturing planning DAM, etc.. The method used to save the DED can be grouped into four formats that are putting in a grid, contours, profiles and TIN (Triangulated Irregular Network). DED can degenerate the existing contours of the data, or from analysis of aerial photographs fotogametri stereo, or it could be from stereo satellite data. Digital Elevation Model (DEM) is a DED that are stored in a grid or raster format, where the elevation data presented sequentially to the columns and rows in the form of cells or the more commonly known as picture element (pixel). Each pixel represents a square-shaped area and are generally square and each pixel has coordinates and information (spatial and time attributes). Data that can be built from the DEM elevation class map, slope map, the map sapek, Sub-watershed maps, water flow direction maps, 3-dimensional maps, etc..