Few battles in history have been more scrutinized than Gettysburg’s three blood-soaked days in July 1863, the turning point in the
Civil War. Still, there were questions that all the diaries, official reports and correspondence couldn’t answer precisely. What, for example, could Gen. Robert E. Lee actually see when he issued a series of fateful orders that turned the tide against the Confederate Army nearly 150 years ago?
Like the crew on the starship Enterprise, humanists are exploring a new frontier of the scholarly universe: space.
“
Mapping spatial information reveals part of human history that otherwise we couldn’t possibly know,” said
Anne Kelly Knowles, a geographer at Middlebury College in Vermont. “It enables you to see patterns and information that are literally invisible.” It adds layers of information to a map that can be added or taken off at will in various combinations; the same location can also be viewed back and forth over time at the click of a mouse.
Today
visitors to Gettysburg can climb to the cupola of the Lutheran seminary, where Lee stationed himself on July 2, the second day of fighting; or stand on Seminary Ridge, where the next day Lee watched from behind the Confederate lines as thousands of his men advanced across the open farmland to their deaths in the notorious Pickett’s Charge. But they won’t see what the general saw because the intervening years have altered the topography. Over the decades a quarry, a reservoir, different plants and trees have been added, and elevations have changed as a result of mechanical plowing and erosion.
Geographic Information Systems, known as GIS, allowed Ms. Knowles and her colleagues to recreate a
digital version of the original Gettysburg battlefield from historical maps, documented descriptions of troop positions and scenery, and renderings of historic roads, fences, buildings and vegetation. “The only way I knew how to answer the question,” about what Lee saw, Ms. Knowles said, “was to recreate the ground digitally using GIS and then ask the GIS program: What can you see from a certain position on the digital landscape, and what can you not see?”
She said her work helps “make Lee’s dilemma more vivid and personal.” Nineteenth-century military leaders relied primarily on their own eyes, and small differences in elevation were strategically important. “Lee probably could not have possibly seen the massive federal forces building up on the eastern side of the battlefield on Day 2 during the famous attack on Little Round Top,” Ms. Knowles said. “He had to make decisions with really inadequate information.”
So did Lt. Gen. James Longstreet, who was vilified in the Confederacy partly because of his decision on July 2 to take his troops on a long countermarch to avoid detection rather than attack Little Round Top directly. The march “made Longstreet the goat of Gettysburg,” Ms. Knowles said. But there was no way that Longstreet could have seen that Little Round Top was undefended at the time. “The analysis says Longstreet made the best decision he could,” added Ms. Knowles, who is currently working on a digital map of the Nazis’ territorial conquests and forced labor camps in Europe.
New methods of computer-assisted geographic analysis can also offer new interpretations of familiar topics. Geoff Cunfer, a historian at the University of Saskatchewan, revisited causes of the 1930s
Dust Bowl by analyzing data from all 208 counties in Texas, New Mexico, Colorado, Oklahoma and Kansas that were affected, an impossible undertaking without this system. He found that the traditional explanation of farmers’ extensively plowing the land without care for environmental limits was only true in some places. Barely plowed Southern counties also suffered from the plague of dust. Using reports of annual precipitation, unplowed grassland, wind direction, droughts, agricultural censuses, historical studies and previous reports on dust storms — “a messy shoebox full of newspaper clippings” — Mr. Cunfer created data sets that could be plotted on maps.
He discovered that dust storms regularly occurred in the 19th century and were a natural part of plains ecology before any plowing occurred, but were “unreported and unpublicized,” he said. ...
