THE SPATIAL AGE AND THE NEW PARADIGMS IN GEODESY: IMPLICATIONS FOR SURVEYING AND MAPPING IN BRAZIL

Abstract

The satellite platforms allowed a very quick transition from local or regional Geodetic Reference Systems (GRSs) to the global ones. The evolution of methods also brought changes in the standards of precision and accuracy. Networks based on local Datums which had relative precision in the order of 1:100,000 to 1:150,000, like the classical networks in the Brazilian Geodetic System (BGS), could be easily replaced by networks constrained in geocentric Datums which reach relative precision of 1:10,000,000 or better and placed inside a concept of a Global Hierarchy. Besides the facilities for positioning, the modern satellite platforms of remote sensors are also applied for satellite altimetry, multi spectral imagery and on-board satellite gravimetry. This allows relevant geodetic information linked directly in global geocentric GRSs. Then, the modern orbital platforms changed completely the ability to capture, model and manage spatial data with strong implications in Geodesy and Cartography. The associated new data bases for Cartography have several new implications coming from the applied surveying methods and present paradigms of precision. Most of the implications come from the need of relating geometric and physical aspects. This happen due the necessary association of local measurements affected by the local gravity field to global oriented geocentric GRS. The modern Global Geopotential Models (GGMs) have a strong expectation for uses in the referred integration. In this paper are discussed the impacts of "spatial age" on the geodetic methods for surveying and mapping. The possible applications of GGMs for realizing fundamental geodetic networks, surveying and mapping are also discussed.