Taboas geraes de toda a navegação / nautical chart

1630 Portuguese map of Asia, with a special focus on Portuguese colonies and trade routes. The title translates to: "General tables of all the navigation, divided and corrected by D. Jeronimo de Ataide, with all the ports and conquests of Portugal delineated by Joao Teixeira, cosmographer of His Majesty, the Year 1630." Taboas geraes de toda a navegação, divididas e emendadas por Dom Ieronimo de Attayde com todos os portos principaes das conquistas de Portugal delineadas por Ioão Teixeira cosmographo de Sua Magestade, anno de 1630

In the 17th century, maps took a huge leap forward. Mathematical and astronomical knowledge necessary to make accurate measurements had evolved. English mathematicians had perfected triangulation: navigation and surveying by right-angled triangles. Triangulation allowed navigators to set accurate courses and produced accurate land surveys. Seamen learned to correct their compasses for declination and had determined the existence of annual compass variation. Latitude determination was greatly improved with the John Davis quadrant. The measurement of distance sailed at sea was improved by another English invention, the common log. Longitudinal distance between Europe and Québec was determined by solar and lunar eclipses by the Jesuit Bressani in the 1640s and by Jean Deshayes in 1686. With accurate surveys in Europe, the grid of the modern map began to take shape.