Starting today, IBGE makes available on the Internet the publication “Monitoramento da Variação das Coordenadas de Estações da Rede SIRGAS” ¹. It presents the results of system monitoring in the period 2003-2010, encompassing the determination of geodetic coordinates (latitude, longitude and altitude) of approximately 130 GNSS stations (Global Navigation Satellite System, similar to the North-American GPS - Global Positioning System) located mainly in the South-American continent.

The monitoring of coordinate generation by the SIRGAS Network through the years has made it possible to detect possible displacement affecting the continent, such as the movement of plates or earthquakes, and more local occurrences, for example, elevations of the land.   

The complete publication is available at

www.ibge.gov.br/home/geociencias/geodesia/default_sirgas_int.shtm?c=11.

In 2005, the Geocentric Reference System for the Americas (SIRGAS) was officially adopted as the new reference for the Brazilian Geodetic System (SGB) and for the National Cartographic System (SCN). It means that, starting in 2014, after a ten-year transition period, only information produced using SIRGAS as reference will be considered official.  A geodetic reference system is a coordinated system, and it allows users to obtain coordinates which can be used in the representation or location, on a map, of any element of the earth’s surface.  

The fundamental difference between SIRGAS and other reference systems previously adopted in Brazil is that the latter are topocentric, that is, their point of origin and orientation is on the Earth’s surface; SIRGAS, on the other hand, is a geocentric system and adopts as its origin a computer-calculated point located in the center of the Earth. By adopting the geocentric reference it is possible to make direct use of GNSS technology, an important tool for the update of maps, control of fleet in transportation companies, and real-time air, sea and land navigation.

Furthermore, the adoption of SIRGAS by the Latin America contributes to the end of a series of problems originated in the discrepancies between the geographic coordinates presented by the GNSS system and those found in maps used in the continent. SIRGAS allows, among other things, the precise integration of cartography of other countries, being indispensable to major cooperative projects such as roads, hydroelectric plants or gas pipelines.

Since 2008, IBGE has been in charge of the SIRGAS Processing Center, which systematically determines the coordinates of stations that belong to the SIRGAS-CON Network (SIRGAS Network of Continuous Operation) in Brazil and in South America. This is one of the eight Centers that belong to an international cooperation project among several countries in the Americas, aimed at maintaining a geodetic reference system of extreme importance to the continent.

Further information about SIRGAS can be obtained at www.sirgas.org.

 ¹ Monitoring of Coordinate Variation in SIRGAS Network Stations