{{Short description|Height of a geographic location above a fixed reference point}} {{Other uses}} {{broader|Vertical position}} {{Distinguish|Elevator}} [[File:vertical distances.svg|thumb|upright=1.4|Vertical distance comparison]] {{pp-move}} The '''elevation''' of a [[geographic]] [[location (geography)|''location'']] is its [[height]] above or below a fixed reference point, most commonly a reference [[geoid]], a [[mathematical model]] of the [[Earth]]'s [[sea level]] as an [[equipotential]] [[gravitation]]al [[equipotential surface|surface]] (see [[Geodetic datum#Vertical datum|Geodetic datum § Vertical datum]]). The term ''elevation'' is mainly used when referring to 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 ''[[three-dimensional space|depth]]'' is used for points below the surface. [[File:Earth elevation histogram 2.svg|thumb|upright=1.5|Elevation [[histogram]] of the Earth's surface]]
Elevation is not to be confused with the distance from the center of the Earth. Due to the [[equatorial bulge]], the summits of [[Mount Everest]] and [[Chimborazo (volcano)|Chimborazo]] have, respectively, the largest elevation and the largest [[ECEF|geocentric]] distance.
==Aviation== In aviation, the term ''elevation'' or ''aerodrome elevation'' is defined by the [[ICAO]] as the highest point of the landing area. It is often measured in feet and can be found in approach charts of the aerodrome. It is not to be confused with terms such as the [[altitude]] or height.<ref>{{Cite book|url=https://www.icao.int/APAC/Meetings/2015%20WAWG1/an14_1ed_1951.pdf|title=AERODROMES|publisher=International Civic Aviation Organisation|year=1951|location=Montreal, Canada|pages=9|access-date=2020-12-19|archive-date=2021-05-07|archive-url=https://web.archive.org/web/20210507043343/https://www.icao.int/APAC/Meetings/2015%20WAWG1/an14_1ed_1951.pdf|url-status=live}}</ref>
[[File:Topomapcropped.jpg|upright=1.3|thumb|Part of a [[topographic map]] of [[Haleakala]] ([[Hawaii]]), showing elevation.]] ==Maps and GIS== [[File:Satellite image of Cape peninsula.jpg|thumb|upright=1.3|[[Landsat]] Image over [[SRTM]] Elevation by [[NASA]], showing the [[Cape Peninsula]] and [[Cape of Good Hope]], [[South Africa]] in the foreground.[http://photojournal.jpl.nasa.gov/catalog/PIA04961] ]]GIS or [[geographic information system]] is a computer system that allows for visualizing, manipulating, capturing, and storage of data with associated attributes. GIS offers better understanding of patterns and relationships of the landscape at different scales. Tools inside the GIS allow for manipulation of data for spatial analysis or cartography. [[Image:srtm ramp2.world.21600x10800.jpg|thumb|upright=1.3|Heightmap of Earth's surface (including water and ice) in [[equirectangular projection]], normalized as 8-bit grayscale, where lighter values indicate higher elevation.]] A [[topographic map|topographical map]] is the main type of [[map]] used to depict elevation, often through [[contour line]]s. In a [[Geographic Information System]] (GIS), [[digital elevation model]]s (DEM) are commonly used to represent the surface (topography) of a place, through a [[raster graphics|raster]] (grid) dataset of elevations. [[Digital terrain model]]s are another way to represent terrain in GIS.
USGS (United States Geologic Survey) is developing a 3D Elevation Program (3DEP) to keep up with growing needs for high quality topographic data. 3DEP is a collection of enhanced elevation data in the form of high quality LiDAR data over the conterminous United States, Hawaii, and the U.S. territories. There are three bare earth DEM layers in 3DEP which are nationally seamless at the resolution of 1/3, 1, and 2 arcseconds.<ref>{{Cite web|url=https://nationalmap.gov/elevation.html|title=The National Map: Elevation|last=Survey|first=U.S. Geological|website=nationalmap.gov|language=en|access-date=2017-02-24|archive-date=2018-06-24|archive-url=https://web.archive.org/web/20180624035829/https://nationalmap.gov/elevation.html|url-status=live}}</ref>
==See also== *[[Amsterdam Ordnance Datum]], {{aka}} ''Normaal Amsterdams Peil'' (NAP), Dutch vertical datum *[[Topographic profile|Elevation profile]] *[[Geodesy]] *[[GTOPO30]] a digital elevation model for the world *[[Hypsometric tints]] *[[Lapse rate]], or the adiabatic lapse rate *[[List of highest mountains on Earth]] *[[List of the highest major summits of North America]] *[[Normalhöhennull]], German vertical datum, literally: ''standard elevation zero'', (NHN) *[[North American Vertical Datum of 1988]], (NAVD 88) **[[Sea Level Datum of 1929]], a superseded United States vertical datum, (NGVD 29) *[[Orthometric height]] *[[Topographic isolation]] *[[Topographic prominence]] *[[Vertical pressure variation]]
==References== {{Reflist}}
==External links== {{Wiktionary|elevation}} *[http://www.ngs.noaa.gov/ U.S. National Geodetic Survey website] **[http://www.ngs.noaa.gov/CORS-Proxy/Glossary/xml/NGS_Glossary.xml Geodetic Glossary @ NGS] **[http://www.ngs.noaa.gov/cgi-bin/VERTCON/vert_con.prl NGVD 29 to NAVD 88 online elevation converter @ NGS] *[http://www.usgs.gov/ United States Geological Survey website] *[http://www.gsi.go.jp/ENGLISH/ Geographical Survey Institute] *[http://www.ngdc.noaa.gov/mgg/fliers/01mgg04.html Downloadable ETOPO2 Raw Data Database (2 minute grid)] {{Webarchive|url=https://archive.today/20121214093625/http://www.ngdc.noaa.gov/mgg/fliers/01mgg04.html |date=2012-12-14 }} *[http://www.ngdc.noaa.gov/mgg/fliers/93mgg01.html Downloadable ETOPO5 Raw Data Database (5 minute grid)] {{Webarchive|url=https://archive.today/20121214000052/http://www.ngdc.noaa.gov/mgg/fliers/93mgg01.html |date=2012-12-14 }} *[https://easycalculator.org/current-elevation Current Elevation]
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[[Category:Geodesy]] [[Category:Topography]] [[Category:Physical geography]] [[Category:Surveying]] [[Category:Geographical terminology in mountaineering]] [[Category:Vertical position]]