July 24, 2009 Mercator's Projection and the Discovery of the Complex Loxodromic Curve to be Discussed at Library of Congress July 29

Press Contact: Donna Urschel (202) 707-1639
Public Contact: John Hessler (202) 707-7223

The Mercator projection—a method of showing a map of the globe on a flat surface—is one of the most important mathematical innovations in the history of cartography. Yet few historians of cartography could explain what it actually is or how it was accomplished.

John W. Hessler, a senior reference librarian in the Geography and Map Division of the Library of Congress and fellow of the Royal Geographical Society, will answer that challenge with his presentation “The Determination of Things Difficult: Mercator’s Projection and the Discovery of the Complex Loxodromic Curve” at noon on Wednesday, July 29, in the Geography and Map Reading Room, in the basement level of the James Madison Building, 101 Independence Ave. S.E., Washington, D.C.

Sponsored by the Geography and Map Division, the event is free and open to the public; tickets and reservations are not required. The lecture is part of the division’s “Map Talk” series.

According to Hessler, the Mercator projection changed forever how the world is perceived, but the story of its invention, how it worked and the derivation of its mathematical machinery is not simple. Flemish geographer and cartographer Gerardus Mercator invented the projection for his famous 1569 World Map. Hessler will provide an overview of the conceptual and mathematical material necessary to understand the projection, and he will provide a commentary of Mercator’s methods, based on Hessler’s forthcoming published translation of Mercator’s 1569 Latin explanation. The lecture will also discuss Edward Wright’s later discovery of the projection’s mathematical underpinnings.

The Library of Congress has the largest and most comprehensive collection of maps and atlases in the world, some 4.8 million cartographic items that date from the 14th century to the present time. The Library's map collections contain coverage for every country and subject, and include the works of the most famous mapmakers throughout history—Ptolemy, Waldseemüller, Mercator, Ortelius and Blaeu. For more information, visit www.loc.gov/rr/geogmap/.


PR 09-146
ISSN 0731-3527