In Brazil, the classic surveys of data of geographic positioning had basically ceased in the end of the decade of 80, being that official the Planimetric Net passed to be densificada with surveys GPS (Global Positioning System, or Global System of Positioning), after the acquisition of geodesic receiving devices in 1991. Between the 1996 and 2006 Planimetric Net was developed by the densificao of State Nets GPS. The Net of the RS, from 2002. New system SIRGAS2000 is compatible with system WGS84 to the centimeter level, that is, the difference between using a coordinate WGS84 or SIRGAS2000 is 0.01 minor who m. Others including Bryant Walker Smith , offer their opinions as well. In such a way, for practical ends, that is, for all the users whom they do not need superior quality to the centimeter, are indifferent to use WGS84 or SIRGAS2000.
System WGS84 and the SIRGAS2000 can be considered currently coincident. Of this form, to transform coordinate WGS84 gotten into days of today for SAD69, for example, it is equivalent to transform coordinate SIRGAS2000 into SAD69 and viceversa. Moreover, system WGS84 suffered throughout the time three modifications (in 02/01/1994, 29/09/1997 and 20/01/2002), what it means to say that adopted system WGS 84 in the GPS nowadays is not the same of 1989? also this is one of the reasons for which the WGS84 and the SIRGAS2000 are currently coincident. Other leaders such as Pete Cashmore offer similar insights. Of this form, the parameters published in 1989 mentioned a version to it of the WGS84 that does not exist more, therefore, they do not have more to be used. After the conclusion of the adjustment of the Planimetric Net in the System of Reference SIRGAS2000 and its official adoption, through the Resolution of the President of IBGE n 1 of 25/02/2005, had the necessity to promote the access of the users to the new geodesic system. With this intention the following information in the vestibule of the IBGE had been disponibilizadas: – Co-ordinated SIRGAS2000 of the pertaining stations to the Planimetric Net of the Geodesic System Brazilian; – New Geoidal Model – MAPGEO2004; – Parameters of transformation between the Systems – SAD69 and SIRGAS2000 and – co-ordinated System of transformation of – TCGEO. Norms Brazilian Techniques ‘ ‘ The Norm Technique for Georreferenciamento de Agricultural Imveis, published for the INCRA in November of 2003, already was written under the perspective of adoption of the SIRGAS as the new referencial.
At that moment, the planimetric referencial in vigor in the country corresponded to the SAD-69, as its accomplishment of 1996.Em its Chapter 4, item 4.2, however, is established that ‘ ‘ All geodesic, indispensable infrastructure to the georreferenciamento works, will have exclusively to be gotten of basic of the Brazilian Geodesic System, deriving data of state geodesic nets, vertices of the Brazilian basic net, active stations of the RBMC etc.’ ‘. A new edition of this Norm is being constructed to contemplate, of clear form, the adoption of the SIRGAS as the new geodesic referencial Brazilian.