Terrain modeling is the process of creating digital representations of the Earth's surface, typically for use in geographic information systems (GIS) or computer-aided design (CAD) applications. This includes the creation of digital elevation models (DEMs), which represent the elevation of the terrain, as well as other features such as land cover, hydrology, and geology. Terrain modeling is used in a wide range of applications, including urban planning, natural resource management, environmental monitoring, and military simulations. It involves the use of remote sensing data, geographic data, and computer algorithms to accurately and realistically represent the Earth's surface in digital form.