"20"^^ . . . . . . . . "In 1841, Congress created the Lake Survey. The Survey, based in Detroit, Mich., was charged with conducting a hydrographical survey of the Northern and Northwestern Lakes and preparing and publishing nautical charts and other navigation aids. The Lake Survey published its first charts in 1852."@en . . . . "Corps of Topographical Engineers"@en . . "In 1841, Congress created the Lake Survey. The Survey, based in Detroit, Mich., was charged with conducting a hydrographical survey of the Northern and Northwestern Lakes and preparing and publishing nautical charts and other navigation aids. The Lake Survey published its first charts in 1852."@en . . "U.S. Army Corps of Topographical Engineers"@en . . . . "--03-31"^^ . . "United States of America"@en . . . . .