What does a Digital Elevation Model (DEM) represent?

A Digital Elevation Model (DEM) represents a terrain surface using a grid of equally spaced elevation values. This grid is made up of a series of points, each reflecting the elevation of the terrain at that specific point. DEMs are created from various data sources, including satellite imagery, aerial surveys, and LiDAR (Light Detection and Ranging) technology, and they provide a continuous surface representation of the earth's topography.

Using equally spaced elevation values allows for accurate modeling of the surface contours and topographical features, making DEMs an essential tool in various applications, such as hydrology analysis, land-use planning, and environmental modeling. The uniform grid structure facilitates computational analyses and the generation of terrain derivatives like slope, aspect, and watershed boundaries, which are crucial for understanding landscape processes.

While a DEM can provide a three-dimensional view of elevation data, this is not its defining trait, as that view can be derived from the model itself. Furthermore, DEMs encompass all terrain features, not just major geographical ones, making a granular representation more valuable for a variety of geographic and scientific inquiries. Thus, option B accurately describes the fundamental purpose and structure of a Digital Elevation Model.