In honor of the 150th anniversary of the Civil War, a collection of maps, charts, and reports prepared by the U.S. Coast Survey, one of NOAA’s predecessor organizations, from 1861 to 1864 is now available from the Internet. The special collection, Charting a More Perfect Union, contains over 400 documents.
Modern hydrographers are constantly surveying the ever-changing U.S. seafloor, which allows NOAA’s Office of Coast Survey to produce thousands of nautical charts. Before the Civil War, however, huge swaths of the young nation’s coast had not been surveyed, but the initial knowledge that was available about water depths, tides and currents, and shore topography provided a valuable advantage for Union strategy.
In 1807, President Thomas Jefferson established the Survey of the Coast to produce the nautical charts necessary for maritime safety, defense, and the establishment of national boundaries. By 1860, the U.S. Coast Survey was the government’s leading scientific agency.
Lincoln’s first actions after the April 1861 attack on Fort Sumter included his “Proclamation of Blockade,” which kept vessels from rebel ports. The goal was to strangle the South’s economy, meaning the unprepared Union navy had to navigate thousands of miles of uncharted coastline. Coast Survey Superintendent Alexander Bache, recognizing that naval navigators lacked domestic nautical charts, quickly set up additional lithographic presses, tripling distribution in the first year of the war.
Just as important as providing charting information for Union troops was the decision to withhold information from others. As Bache pointed out, “it has been judged expedient during the past year to suspend usual foreign distribution” of charting reports. Because Coast Survey could not easily ascertain the loyalties of private citizens, chart distribution was severely restricted, “the cases of applicants who were not well known having been referred to the representative of the congressional district from which the application had been mailed.”
In other words, keep nautical charts out of Southern hands.
Acquiring nautical data became difficult, starting with rebels seizing tidal gauges in Louisiana, and worse. Bache sent men to work with blockading squadrons and armies in the field. One topographer was with the siege at Vicksburg in 1863:
“Yesterday, I was three miles beyond our pickets and within 600 yds of the enemy’s batteries. I did not stop work till the cannon balls plowed up the ground within 20 feet of us. One of my men had his hat blown off by the wind of a ball and one struck the levee just under my plane table. I reckon about all of the inhabitants of Vicksburg were out after me…”
The topographer eventually died of illness contracted at Vicksburg, but he completed his chart “Approaches to Vicksburg.”
