A Digital Elevation Model (DEM) is a digital representation of ground surface topography or terrain. It's a raster dataset composed of cells, each containing an elevation value. DEMs are fundamental datasets used in a wide range of applications, including geographic information systems (GIS), remote sensing, surveying, and engineering. They provide a basis for terrain analysis, visualization, and modeling. Common uses include creating contour maps, calculating slope and aspect, generating 3D visualizations of landscapes, simulating water flow, and planning infrastructure projects. The accuracy and resolution of a DEM are crucial factors determining its suitability for specific applications. Higher resolution DEMs capture more detailed terrain features, while higher accuracy DEMs provide more reliable elevation values. DEMs are often derived from various sources, such as satellite imagery, aerial photography, LiDAR (Light Detection and Ranging), and ground surveys. Different DEM formats exist, each with its own specific structure and characteristics, but the underlying principle remains the same: to represent the elevation of the Earth's surface in a digital format.