What does a Digital Elevation Model (DEM) represent?

A Digital Elevation Model (DEM) is a digital representation of the Earth's surface terrain that specifically captures elevation data. It provides a 3D representation of the terrain, allowing users to understand the topography of an area. DEMs are generated from various data sources, including satellite imagery and aerial surveys, and they illustrate ground elevation as a continuous surface rather than just isolated points.

The importance of a DEM lies in its ability to facilitate a range of applications, such as hydrological modeling, landscape visualization, and infrastructure planning. Users can analyze slope, aspect, and watershed delineation and perform viewshed analyses. The structured data in a DEM allows for more sophisticated geospatial analyses compared to simpler representations.

In contrast, the other choices do not accurately reflect the nature of a DEM. A simplified 2D map of urban areas captures flat, two-dimensional representations without elevation data. Aerial photographs primarily focus on capturing images of land use, not terrain elevation. Lastly, satellite imagery consists of images capturing the Earth’s surface and does not create a 3D representation of elevation like a DEM does.