Elevation is the distance above sea level of a given location. Sea level is the level of the ocean averaged between mean high and low tides. However, Earth is not a perfect circle, it is an ellipse. To account for this geographers calculate a geoid, an imaginary wavy line encircling Earth and representing mean sea level. This allows us to measure the elevation of mountains such as Mount Everest (8,849 meters or 29,032 feet) or the depth of an earthquake with more precision as we can clearly state the geoid we used. This map layer uses the World Geodetic System (WGS84) geoid which is the industry standard for global positions systems (GPS).

This map layer uses the shaded relief technique, which when applied to terrain data represents elevation. In the shaded relief technique, light is simulated and added to a map layer to better illustrate topography. In this map, the light assumes the sun has a solar altitude of 45 degrees and a solar aspect of 315 degrees.

Topography provides a picture of Earth’s surface that allows scientists to study how water moves through a landscape, what low-lying areas may be prone to floods, and regions susceptible to landslides.

Topography and elevation impact a location's temperature, the amount of precipitation it receives, and as a result of those two, the vegetation that can grow there. As elevation increases, temperature decreases. This occurs when warm air rises then expand due to the decrease in air pressure. This warm air is often also moist. As it rises clouds form and continued condensation can cause precipitation. The air may then pass over the point of high elevation and sink, warming as it does. This is called the rain shadow effect or orographic precipitation. The amount of available precipitation and the temperature result in different types of vegetation in different locations. Turn on the precipitation layer, do you see any evidence of the rain shadow effect? Where?