Editing Mount Everest (section)

===20th century===
[[File:CH-NP 79-80 Bdy Map50.jpg|thumb|Published by the Survey of [[Nepal]], this is Map 50 of the 57 map set at 1:50,000 scale "attached to the main text on the First Joint Inspection Survey, 1979–80, [[Nepal]]-China border." At the top centre, a boundary line, identified as separating "China" and "Nepal", passes through the summit contour. The boundary here and for much of the [[China–Nepal border]] follows the main Himalayan watershed divide.]]
<!--[[File:CH-NP 79-80 Bdy Map50.jpg|thumb|Published by the Survey of Nepal, this is Map 50 of the 57 map set at 1:50,000 scale "attached to the main text on the First Joint Inspection Survey, 1979–80, Nepal-China border." At the top centre, a boundary line, identified as separating "China" and "Nepal", passes through the summit contour. The boundary here and for much of the China-Nepal border follows the main Himalayan watershed divide.]]-->
[[File:ISS004E8852 everest.jpg|thumb|right|[[Kangshung Face|Kangshung Face (the east face)]] as seen from orbit]]

In 1856, Andrew Waugh announced Everest (then known as Peak XV) as {{convert|29002|ft|m|abbr=on|order=flip}} high, after several years of calculations based on observations made by the [[Great Trigonometrical Survey]].<ref>{{Cite book|last=Krakauer|first=Jon|title=Into Thin Air: A Personal Account of the Mount Everest Disaster|publisher=Anchor Books|year=1997|isbn=978-0-385-49478-6|edition=First|location=New York|pages=15–16|oclc=36130642}}</ref> 
From 1952 to 1954, the [[Survey of India]], using [[triangulation]] methods, determined that the height of Everest was {{convert|8847.73|m|ft|0|abbr=on}}.<ref name="everest-height-1952-1954">{{cite web |url=https://archive.org/details/Everest_201304 |title=Technical Paper No. 8, The Height of Mount Everest a New Determination (1952–1954) |last=Gulatee |first=Bihari Lal |publication-date=10 May 1955 |publisher=[[Indian Agricultural Research Institute]] |location=New Delhi, India |access-date=2 June 2023}}</ref> In 1975 it was subsequently reaffirmed by a Chinese measurement of {{convert|8848.13|m|ft|2|abbr=on}}.<ref name=ABC_au/> In both cases the snow cap, not the rock head, was measured.
The {{convert|8848|m|ft|0|abbr=on}} height given was officially recognised by Nepal and China.<ref>{{cite news |url=http://news.bbc.co.uk/1/hi/world/south_asia/8608913.stm |title=Nepal and China agree on Mount Everest's height |work=BBC News |date=8 April 2010 |access-date=22 August 2010 |archive-date=3 March 2012 |archive-url=https://web.archive.org/web/20120303133522/http://news.bbc.co.uk/1/hi/world/south_asia/8608913.stm |url-status=live }}</ref> Nepal planned a new survey in 2019 to determine if the [[April 2015 Nepal earthquake]] affected the height of the mountain.<ref>{{cite news |last1=Daley |first1=Jason |title=Nepalese Expedition Seeks to Find Out if an Earthquake Shrunk Mount Everest Read |url=https://www.smithsonianmag.com/smart-news/nepalese-expedtion-wants-find-out-if-earthquake-shrunk-mount-everest-180971963/ |work=Smithsonian.com |publisher=Smithsonian Magazine |date=15 April 2019 |access-date=28 August 2019 |archive-date=31 May 2023 |archive-url=https://web.archive.org/web/20230531075731/https://www.smithsonianmag.com/smart-news/nepalese-expedtion-wants-find-out-if-earthquake-shrunk-mount-everest-180971963/ |url-status=live }}</ref>

In May 1999, an American Everest expedition directed by [[Bradford Washburn]] anchored a [[Global Positioning System|GPS]] unit into the highest bedrock. A rock head elevation of {{convert|8850|m|ft|0|abbr=on}}, and a snow/ice elevation {{convert|1|m|ft|0|abbr=on}} higher, were obtained via this device.<ref name="alpres">{{cite web|url=http://www.alpineresearch.ch/alpine/en/presse1.html|archive-url=https://web.archive.org/web/20070103165811/http://www.alpineresearch.ch/alpine/en/presse1.html|archive-date=3 January 2007|title=Elevation of Mount Everest newly defined|publisher=Swiss Foundation for Alpine Research|date=12 November 1999|access-date=1 April 2007}}</ref> Although as of 2001, it has not been officially recognised by Nepal,<ref>{{cite web|url=http://www.nepalgov.gov.np/countryprofile.php|title=Country Profile|publisher=Government of Nepal|year=2001|access-date=1 April 2007|archive-url = https://web.archive.org/web/20070314011131/http://www.nepalgov.gov.np/countryprofile.php |archive-date = 14 March 2007}}</ref> this figure is widely quoted. [[Geoid]] uncertainty casts doubt upon the accuracy claimed by both the 1999 and 2005 (see [[#21st-century surveys|§ 21st-century surveys]]) surveys.<ref>{{Cite web|last=US Department of Commerce|first=NOAA|title=GEOID18 Technical Details {{!}} GEOID18 {{!}} National Geodetic Survey|url=https://geodesy.noaa.gov/GEOID/GEOID18/geoid18_tech_details.shtml|access-date=9 March 2021|website=geodesy.noaa.gov}}</ref>

In 1955, a detailed [[Photogrammetry|photogrammetric]] map (at a scale of 1:50,000) of the [[Khumbu]] region, including the south side of Mount Everest, was made by [[Erwin Schneider]] as part of the 1955 International Himalayan Expedition, which also attempted [[Lhotse]].

In the late 1980s, an even more detailed [[topography|topographic]] map of the Everest area was made under the direction of Bradford Washburn, using extensive [[aerial photography]].<ref name="washburn_map"/>