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Plan de la Baye de la Coquimbo. - Public domain old map
Summary
Relief shown pictorially.
Oriented with north to the left.
Watermarks: Cluster of grapes and indecipherable lettering.
Pen-and-ink and watercolor.
On verso with notes and index: Les Isles de Dn. Juan Fernandes situées par les 33 d. 30 m. de lattitude sud.
LC Luso-Hispanic World, 204
Available also through the Library of Congress Web site as a raster image.
Maggs number annotated in pencil in lower right margin: 209.
Annotated in pencil on verso: 366082 27.
Vault
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.
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