{{Geodesy}} The '''South American Datum''' ('''SAD''') is a regional historical [[geodetic datum]] for [[South America]]. The most common version was established in 1969 (''SAD69''), as adopted by the [[Pan American Institute of Geography and History]].<ref name="Fischer1970">{{cite journal | last=Fischer | first=Irene | title=The Development of the South American Datum 1969 |author-link=Irene Fischer | journal=Survey Review | publisher=Informa UK Limited | volume=20 | issue=158 | year=1970 | issn=0039-6265 | doi=10.1179/sre.1970.20.158.354 | pages=354–365| bibcode=1970SurRv..20..354F }}</ref>
It uses as [[reference ellipsoid]] the [[Geodetic Reference System]] 1967 (GRS-67), recommended by the [[International Union of Geodesy and Geophysics]] in [[Lucerne]] in 1967.<ref>{{Cite web| title=Resolutions of the Union and of the Associations | url=http://www.iugg.org/resolutions/zurich.pdf | archive-url=https://web.archive.org/web/20060518090359/http://www.iugg.org:80/resolutions/zurich.pdf | archive-date=2006-05-18}}</ref> This ellipsoid acquired topocentric orientation defined at the [[Astrogeodesy|astrogeodetic]] [[geodetic mark|vertex]] ''Chuá'', in the municipality of [[Uberaba]], Brazil.<ref>{{Cite web| title=Sistemas de referência | language=pt | trans-title=Reference systems | url=https://geoftp.ibge.gov.br/informacoes_sobre_posicionamento_geodesico/sirgas/sisref_2.pdf | archive-url=https://web.archive.org/web/20190126074625/http://geoftp.ibge.gov.br/informacoes_sobre_posicionamento_geodesico/sirgas/sisref_2.pdf | archive-date=2019-01-26}}</ref><ref>{{cite journal | last1=Sampaio | first1=Antonio Carlos Freire | last2=Sampaio | first2=Adriany de Ávila Melo | last3=Cerissi | first3=Bruna Costa de Oliveira | last4=Silva | first4=Rafael Tiago dos Santos | title=VÉRTICE CHUÁ - SUA SITUAÇÃO E A NECESSIDADE DE PRESERVAÇÃO DE MONUMENTOS DA CARTOGRAFIA HISTÓRICA BRASILEIRA | journal=Revista Brasileira de Cartografia | volume=67 | issue=4 | date=2019-06-11 | issn=1808-0936 | pages=877–885 | doi=10.14393/rbcv67n4-49126 | s2cid=196088639 | url=http://www.seer.ufu.br/index.php/revistabrasileiracartografia/article/view/49126 | language=pt | access-date=2021-07-02| doi-access=free }}</ref>
This datum was subsequently adopted by many South American countries, including the earlier ''Brazilian Geodetic System'' (''Sistema Geodésico Brasileiro'' - ''SGB''). In most countries, SAD was recently replaced by [[SIRGAS]]; for example, in Brazil SIRGAS was adopted starting in 2005 and mandated since 2014.<ref name="IBGE 2005">{{cite web | title=Transformation of Coordinates among Official Referential Systems | website=IBGE | date=2005-02-25 | url=https://www.ibge.gov.br/en/geosciences/geodetic-positioning/services-for-geodetic-positioning/20144-transformation-of-coordinates-among-official-referential-systems.html?=&t=o-que-e | access-date=2021-07-02}}</ref>
==References== {{reflist}}
[[Category:Geodetic datums]]
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