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Elevation

geography Maturity 7-9 Next article →

Elevation tells us how high a spot is on Earth. It measures the vertical distance from a fixed starting point. Most people use a model of sea level as this starting point. Scientists call this mathematical model a geoid.

vertical distances
vertical distances

It is important to use the right words for height. We use the word elevation for points on the land. We use altitude for things high in the air, like planes. We use depth for things far below the surface.

Earth elevation histogram 2
Earth elevation histogram 2

Measuring height can be tricky because Earth is not a perfect sphere. The middle of our planet bulges outward. This means elevation is not the same as distance from the center. Mount Everest has the highest elevation on the planet. However, the peak of Chimborazo is further from the Earth's center.

srtm ramp2.world.21600x10800
srtm ramp2.world.21600x10800

This happens because of that bulge at the equator. Pilots must also know about elevation when they land. They look at the aerodrome elevation on their charts. This is the highest point of the landing area.

vertical distances
vertical distances

People use many tools to map the shape of the land. Topographic maps are a main way to show elevation. These maps often use contour lines to show hills.

Topomapcropped
Topomapcropped

Today, we also use Geographic Information Systems, or GIS. A GIS is a computer system for storing land data. It helps us see patterns in the landscape. We can use these tools to make maps for many jobs.

Satellite image of Cape peninsula
Satellite image of Cape peninsula

Computers create digital models to represent the surface of the Earth. These are called digital elevation models, or DEMs. They use a grid of data to show the topography. Digital terrain models are another way to show this.

srtm ramp2.world.21600x10800
srtm ramp2.world.21600x10800

In the United States, the USGS is working on a big project. It is called the 3D Elevation Program, or 3DEP. This program uses high quality LiDAR data to map the land. It covers the United States, Hawaii, and U.S. territories.

Satellite image of Cape peninsula
Satellite image of Cape peninsula

Understanding elevation helps us study our whole world. We can use these maps to see how land changes. Scientists use different layers of data to be very precise. For example, 3DEP has three different layers for the bare earth. These layers are seamless across the country.

Topomapcropped
Topomapcropped

Whether we are flying a plane or hiking a hill, elevation matters. It helps us know exactly where we are standing. It connects the ground beneath us to the sea level.

Earth elevation histogram 2
Earth elevation histogram 2
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🖼️ Images & Media (5)
File:vertical distances.svg
vertical distances.svg
File:Earth elevation histogram 2.svg
Earth elevation histogram 2.svg
File:Topomapcropped.jpg
Topomapcropped.jpg
File:Satellite image of Cape peninsula.jpg
Satellite image of Cape peninsula.jpg
File:srtm ramp2.world.21600x10800.jpg
srtm ramp2.world.21600x10800.jpg
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