What is the Difference Between Elevation and Altitude?

Caitlin Dempsey


While the geography terms elevation and altitude are often used interchangeably, they have slightly different meanings.

What is Elevation?

Elevation is the measurement of the height of a geographical feature that is above mean sea level (MSL). This means that elevation is the distance from the height that represents the surface of the ocean up to the top of the feature.

Elevation uses a fixed reference point, mean sea level, from which these features are measured. Elevation measures the height of things that are on the ground.

What is Altitude?

In geography, altitude is the height of an object above the surface of the ground or sea level based on a datum, a geodetic reference point. Altitude is the vertical measurement of the distance of an object above the surface of the Earth.

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For example. the height of a plane in the sky is known as that machine’s altitude.

Likewise, satellites are placed at specific altitudes above Earth.

A image of a mountain with the black silhouette of a bird of prey flying with annotations to show the difference between elevation and altitude.

True Versus Absolute Altitude

In aviation, there are five types of altitude. Two of the types are true altitude and absolute altitude.

As with the geography term altitude, true altitude is the altitude the airplane above mean sea level. True altitude is expressed as the distance above mean sea level (MSL).

Absolute altitude is the distance between the airplane and the height of the ground below the airplane. Absolute altitude is expressed as the distance above ground level (AGL).

A photo of a mountain with two birds in black fly above with labels to show the difference between true altitude and absolute altitude.

What is Negative Altitude?

Altitude can be negative if the object is below the surface of the ground. For example, if a bird were to fly into a canyon that is below mean sea level, the altitude of that bird’s flight would be negative.

What is High-Altitude?

It can be a bit confusing about differentiating the two terms when the term for features that are at very high elevations are called “high-altitude”. Geographic areas are considered “high-altitude” if they are above an elevation of 8,000 feet (2,400 meters).

Depth in Geography

When an object is measure from how far below the surface of the Earth it is, that is known as the depth.

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About the author
Caitlin Dempsey
Caitlin Dempsey is the editor of Geography Realm and holds a master's degree in Geography from UCLA as well as a Master of Library and Information Science (MLIS) from SJSU.