Observational astronomy and the mapping of Brazil at the turn of the 20th century

When, in 1822, Brazil declared its independence from Portugal, its vast territory was little known by the central government in Rio de Janeiro. There was a great need to create reliable maps that would delineate the new country’s boundaries. This paper aims to show how a practical application of astronomy, specifically geodesy, was vital in the efforts to build the nation. We follow the professional life of an astronomer, Luis Cruls, director of the National Observatory, professor at the Military School and chief researcher of several expeditions, to discuss the strength of geodesic and cartographic activities in Brazil at the end of the 19th century.