Elevation
Height above a reference geoid, distinct from altitude and depth.
Elevation is a measurement of the height of a point on the Earth's surface above or below a fixed reference point, most commonly a reference geoid, which is a mathematical model of the Earth's sea level as an equipotential gravitational surface. The term is primarily used for points on the Earth's surface, while altitude or geopotential height is used for points above the surface, such as an aircraft in flight or a spacecraft in orbit, and depth for points below. It is important to distinguish elevation from the distance to the center of the Earth; due to the equatorial bulge, the summit of Mount Everest has the greatest elevation, whereas the summit of Chimborazo has the greatest geocentric distance.
In aviation, the International Civil Aviation Organization defines elevation, or aerodrome elevation, as the highest point of the landing area. This value is often measured in feet and appears on approach charts, and it should not be confused with the altitude or height of an aircraft. Topographic maps are the primary cartographic tool for depicting elevation, typically using contour lines. In geographic information systems, digital elevation models (DEMs) represent surface topography through raster datasets of elevations, while digital terrain models offer another method of representation. The United States Geological Survey is developing the 3D Elevation Program to meet growing demands for high-quality topographic data, which includes high-quality LiDAR data for the conterminous United States, Hawaii, and U.S. territories. This program provides three bare-earth DEM layers that are nationally seamless at resolutions of 1/3, 1, and 2 arcseconds.
- field
- Geography, Aviation, Geodesy
- known_for
- Measurement of height above a reference geoid; distinction from altitude and depth; use in topographic maps and GIS
- related_terms
- Altitude, Geopotential height, Depth, Geocentric distance
- key_organizations
- ICAO, USGS
- notable_examples
- Mount Everest (largest elevation), Chimborazo (largest geocentric distance)
Lore & Background
Elevation refers to the height of a geographic location above or below a fixed reference point, most commonly a reference geoid—a mathematical model of Earth’s sea level as an equipotential gravitational surface. This term is primarily used for points on the Earth’s surface, whereas altitude or geopotential height applies to points above the surface, such as an aircraft in flight or a spacecraft in orbit, and depth is used for points below the surface. Elevation should not be confused with the distance from the center of the Earth; due to the equatorial bulge, Mount Everest has the largest elevation, while Chimborazo has the largest geocentric distance. In aviation, the International Civil Aviation Organization defines elevation, or aerodrome elevation, as the highest point of the landing area, often measured in feet and included in approach charts. Topographic maps are the main type of map used to depict elevation, typically through contour lines. In geographic information systems (GIS), digital elevation models (DEM) represent the surface topography of a place using raster (grid) datasets of elevations, while digital terrain models offer another method. The United States Geological Survey is developing a 3D Elevation Program (3DEP) to meet growing needs for high-quality topographic data, consisting of enhanced elevation data from high-quality LiDAR over the conterminous United States, Hawaii, and U.S. territories, with three bare-earth DEM layers that are nationally seamless at resolutions of 1/3, 1, and 2 arcseconds.
Reader's Guide
Elevation describes the vertical distance of a location on the Earth’s surface relative to a fixed reference point, most commonly a reference geoid—a mathematical model of sea level as an equipotential gravitational surface. This distinguishes it from altitude, which applies to points above the surface like aircraft or spacecraft, and depth, used for points below. Elevation is not the same as distance from the Earth’s center; due to the equatorial bulge, Mount Everest holds the greatest elevation, while Chimborazo has the largest geocentric distance. In aviation, the International Civil Aviation Organization defines aerodrome elevation as the highest point of the landing area, measured in feet and noted on approach charts. In geography and cartography, topographic maps primarily depict elevation through contour lines. Within geographic information systems (GIS), digital elevation models (DEMs) represent surface topography via raster datasets of elevations, while digital terrain models offer an alternative representation. The United States Geological Survey is developing the 3D Elevation Program (3DEP) to address increasing demand for high-quality topographic data, utilizing LiDAR data across the conterminous United States, Hawaii, and U.S. territories, producing three bare earth DEM layers at resolutions of 1/3, 1, and 2 arcseconds. This concept underpins fields from geodesy to spatial analysis, enabling visualization and understanding of landscape patterns and relationships at various scales.
Did You Know?
- Elevation is not to be confused with the distance from the center of the Earth; Mount Everest has the largest elevation, while Chimborazo has the largest geocentric distance.
- In aviation, the ICAO defines aerodrome elevation as the highest point of the landing area.
- The USGS 3D Elevation Program (3DEP) provides three bare earth DEM layers at resolutions of 1/3, 1, and 2 arcseconds.
- A topographical map is the main type of map used to depict elevation, often through contour lines.
Frequently Asked Questions
What is Elevation in geography?
Elevation describes how far a point on Earth's surface sits above or below a standardized reference level, typically the geoid. It is the standard term used on topographic maps and in GIS to express the vertical position of land features.
How does Elevation differ from Altitude and Depth?
Elevation applies specifically to points on the Earth's surface, whereas altitude (or geopotential height) describes objects above the surface such as aircraft, and depth measures how far below the surface something lies. Keeping these three terms separate prevents confusion across geography, aviation, and oceanography.
What is the geoid and why is it the reference for Elevation?
The geoid is a mathematical model of Earth's sea level defined as an equipotential gravitational surface, and it serves as the baseline from which elevation is measured. Without this shared reference, comparing heights between different locations would lack consistency.
What are some notable Elevation examples?
Mount Everest holds the record for the greatest elevation above sea level, while Chimborazo in Ecuador actually sits farthest from Earth's center because of the planet's equatorial bulge. These two peaks show that the 'highest' point depends on whether you measure elevation or geocentric distance.
Which organizations set standards for Elevation measurement?
The ICAO governs height-related standards in aviation, while the USGS produces the topographic data where elevation figures appear for the general public. Together they ensure that elevation values are reported consistently in their respective fields.
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