Terrain

Present-day Earth altimetry and bathymetry. Data from the National Geophysical Data Center's TerrainBase Digital Terrain Model.
Relief map of Sierra Nevada, Spain
A shaded and colored image (i.e. terrain is enhanced) of varied terrain from the Shuttle Radar Topography Mission. This shows an elevation model of New Zealand's Alpine Fault running about 500 km (310 mi) long. The escarpment is flanked by a vast chain of hills between the fault and the mountains of the Southern Alps. Northeast is towards the top.

Terrain or relief (also topographical relief) involves the vertical and horizontal dimensions of land surface. The term bathymetry is used to describe underwater relief, while hypsometry studies terrain relative to sea level. The Latin word terra (the root of terrain) means "earth."

In physical geography, terrain is the lay of the land. This is usually expressed in terms of the elevation, slope, and orientation of terrain features. Terrain affects surface water flow and distribution. Over a large area, it can affect weather and climate patterns.