What is the primary function of a digital elevation model (DEM) in GIS?

The primary function of a digital elevation model (DEM) in GIS is to represent terrain elevation and analyze surface features. DEMs are essential tools in geographic information systems because they provide a three-dimensional representation of the Earth's surface, reflecting variations in elevation. This capability allows users to visualize terrain, analyze topography, and model surface hydrology, among other applications.

By using DEMs, GIS professionals can perform analyses such as slope calculations, watershed and drainage modeling, and viewshed analysis. These analyses are crucial for activities like urban planning, environmental management, and disaster response, where understanding the landscape's features and dynamics is critical.

The other options do not capture the primary purpose of a DEM; enhancing the aesthetic appeal of maps is more about cartographic design than topographic analysis, storing large datasets in the cloud relates to data management rather than analysis, and facilitating real-time data collection does not align with the static nature of DEMs, which represent fixed elevation data rather than dynamic collections.