Cartography in the administration of Portuguese America can be related to three major processes—first, to allow the exploration and occupation of territory from the coast to the interior; second, to improve the organization of the colonial administration system; and third, as a basis for diplomatic negotiations of territory with other European nations. Between the 16th and 17th centuries, during the Atlantic maritime expansion through which new lands and new worlds were unveiled to Europeans, the Portuguese constructed a solid cartographic mapping of Brazil—a process in which they were the pioneers. The objective was to allow their vessels to cross the ocean and afterward to guarantee their dominion over the newly discovered lands, which resulted in a progressive increase of geographic knowledge of the world that was being unveiled to the Europeans. For these reasons, maps produced during these two centuries showed the increasing expectations and knowledge of the New World and reflected the manner of how the Americas, particularly Brazil, were gaining visibility among the European public; the maps satisfied the public’s curiosity about the recently discovered lands, with information related to geography and nature.
Initially, as Spanish, Portuguese, and even French explorers began to reach the west coast of the continent, parts of the coastline began to appear on Portolan charts, which were used at that time for maritime sailing and are very rare today. Later the cartographers started portraying the interior of Brazil. Representations of local geography began to progressively replace images of natives and local flora and fauna. It became common on 17th-century maps to design a chain of rivers that allowed Brazil to be portrayed as an island. It was not by chance that this representation appeared in Portuguese maps at the same time as the Spanish and Portuguese crowns were unified, from 1580 to 1640. In the 17th and 18th centuries administrative cartography was mostly performed and supervised from Portugal by the Portuguese Crown or the Overseas Council, which handled all colonial policy.
Two features characterized this activity: the impact of Portuguese colonization as it moved toward the western and central regions of the continent; and technical changes to cartographic practice that began at this time, characterized by Enlightenment rationality. The discovery of gold in the southeastern and central-west regions of Brazil, the Portuguese exploration of the Amazon basin, and the incessant disputes between the Spanish and Portuguese over Colonia del Sacramento in the south demanded better definition of both internal and external frontiers. Internal frontiers included divisions between captaincies, comarcas (a subdivision of captaincies originally of an ecclesiastical nature), bishoprics, and various other administrative divisions. External frontiers, by contrast, usually represented borders with Spanish American colonies.