It is as if each referencial was a different language and needed a translator for the mutual agreement in the communication. For this, each time more comes if adopting in the world all, a geodesic referencial for the localization in the surface of the Planet. Geodesy is science (form studies and dimensions of Land) that it considers the possible Land next to the form that it possesss, that is, as one geide, well next geometric figure to a sphere, as our Planet. Throughout the years, in the elaboration of maps and geographic cadastros, more currently with the advance and use of informatizados systems of geographic information, innumerable referenciais exist, which possess denominations in accordance with its origin, localization, etc. Currently, the used techniques more of positioning stops locating in them on the Land, is those that they use compatible referenciais with the existing space technology, that is, compatible with the technology disponibilizada for the artificial satellites that gravitate the Planet. Because as much geodesy as the technology of the satellites assumes that the Land possesss an only central point (geocentro), as if all the mass could be intent in this point. That is, the use of artificial satellites for positioning needs an adjusted referencial, called ' ' referencial geocntrico' '. In the case, the new system, Sirgas, are a geocentric, compatible referencial system with the positioning technology most modern.
The traditional systems of positioning (as SAD69, etc.) had as base topocntrica orientation, that is, the origin point and orientation is in the terrestrial surface, consequentemente needing parameters of adjustment between itself for the had conversions and uses. The adoption of referencial SIRGAS2000 was officialized in 25/02/2005, through the Resolution of the Presidency of the IBGE in the 1/2005 (IBGE, 2005). It was established from a continental campaign GPS carried through of 10 the 19 of May of 2000, when 184 stations had been busy in Americas, of which 21 situated ones in Brazilian territory.