South American Datum

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.^[1]

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.^[2] This ellipsoid acquired topocentric orientation defined at the astrogeodetic vertex Chuá, in the municipality of Uberaba, Brazil.^[3][4]

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.^[5]

References

1. Fischer, Irene (1970). "The Development of the South American Datum 1969". Survey Review. 20 (158). Informa UK Limited: 354–365. Bibcode:1970SurRv..20..354F. doi:10.1179/sre.1970.20.158.354. ISSN 0039-6265.
2. "Resolutions of the Union and of the Associations" (PDF). Archived from the original (PDF) on 2006-05-18.
3. "Sistemas de referência" [Reference systems] (PDF) (in Portuguese). Archived from the original (PDF) on 2019-01-26.
4. Sampaio, Antonio Carlos Freire; Sampaio, Adriany de Ávila Melo; Cerissi, Bruna Costa de Oliveira; Silva, Rafael Tiago dos Santos (2019-06-11). "VÉRTICE CHUÁ - SUA SITUAÇÃO E A NECESSIDADE DE PRESERVAÇÃO DE MONUMENTOS DA CARTOGRAFIA HISTÓRICA BRASILEIRA". Revista Brasileira de Cartografia (in Portuguese). 67 (4): 877–885. doi:10.14393/rbcv67n4-49126. ISSN 1808-0936. S2CID 196088639. Retrieved 2021-07-02.
5. "Transformation of Coordinates among Official Referential Systems". IBGE. 2005-02-25. Retrieved 2021-07-02.