- The Washington Times - Friday, January 26, 2007

The art of mapmaking took on new prominence during the Civil War because military commanders needed reliable maps of the region in which they were operating.

Most maps that existed at the outset of hostilities were inaccurate and also lacked the details necessary for operational purposes. Historian T. Harry Williams noted that “a fact vital to an understanding of what happened in many battles, is that both sides began the struggle with no reliable maps of the area in which they would fight.”

The reason was the absence of a need for maps by the general public. People stayed close to home in those days. If they traveled at all, they went mostly by train and steamboat, which did not require the use of maps. Ironically, maps were especially scarce in the South, where the war would be fought. During the Seven Days Campaign in 1862, Confederate Gen. Richard Taylor complained, “Confederate commanders knew no more about the topography of the [surrounding] country … than they did about Central Africa.”

The Federal government was better prepared than the Confederacy to produce wartime maps through its Corps of Topographical Engineers, the U.S. Coast and Geodetic Survey and other agencies. These organizations produced maps that were general or strategic in nature, but they often based their work on existing defective maps.

Given a paucity of quality maps to guide it, the Union Army was at a disadvantage in Southern territory because Confederates, despite Taylor’s concerns, were more familiar with the landscape. This disadvantage was offset partially by information derived from cooperative slaves and free blacks in the South who had intimate knowledge of the areas they inhabited.

Because the Confederate government lacked a topographical branch at the beginning of the war, Gen. Robert E. Lee endorsed the establishment of a mapmaking unit in mid-1862. Though not as proficient as its Northern counterpart, it worked hard to keep its mapmakers supplied with materials.

Based on experience during the Mexican War, Lee advised his engineers that reconnoitering alone or in small groups was the most effective way to get close enough to sketch enemy positions. W.W. Blackford, an engineer in Gen. J.E.B. Stuart’s cavalry, employed this method. He normally took just three men along while scouting the terrain. He also made it a point to reconnoiter the aftermath of a battle.

Blackford did this to determine the strength of the positions and “the effect of fire” based on the casualties still on the field, which would allow him to evaluate the accuracy of his maps. A basic responsibility of topographical engineers was to prepare a map of the ground on which battles were fought to accompany after-action reports.

While exploring terrain in the countryside, army engineers frequently were vulnerable to enemy fire or capture. Even friendly scouts and outposts at times interrupted their work and marched the engineers to camp for identification.

Commanders in the field required specific maps of their operational areas. Experience demonstrated that timeliness was more important than accuracy in preparing maps for tactical purposes because the enemy often overran a position before a map could be completed.

Though timeliness was a critical factor in combat conditions, long-range planning permitted the end product to be more elaborate and detailed. Confederate topographical engineer Jed Hotchkiss’ maps of the Shenandoah Valley in 1862 fit this category. Because armies traveled with heavy wagon trains and artillery, it was especially important to identify points on these maps where streams and rivers could be crossed.

One of the main duties of staff engineers was to reconnoiter the enemy and produce accurate topographical sketches of their position and strength. Typically the engineers would be at work on horseback, sketching the terrain on a scrap of paper. They made special note of the extent and nature of wooded areas where the enemy could be hiding and where it was difficult to employ cavalry and artillery. Other natural features, such as hills and mountains, also were observed because they were keys to holding ground and winning battles. Marching armies often lived off of the land, so maps routinely included potential sources of supply, such as taverns, hotels, general stores, stables and blacksmiths.

When commanders were unfamiliar with the terrain, one option was to employ a reconnaissance-in-force to capture the ground so engineers could sketch and map the area. The information obtained and graphically depicted for commanders was a key ingredient in combat decision-making, especially because successful operations frequently depended on the availability and condition of roads.

Maps sometimes were acquired by capturing them during raids of enemy camps or by taking them from prisoners and casualties on the battlefield. These maps then could be used as they were or as the basis for creating other maps of a particular area. Questioning enemy stragglers or local residents about surrounding terrain proved valuable, especially if done by a resourceful and perceptive interrogator.

The end product of this combined activity generally included a sketch of the terrain the army would travel, identification of the potential battlefield, and a better understanding of the enemy’s intentions. Multiple sources, such as surveys, reconnaissance, interviews of knowledgeable people, existing maps, related documents and engineering reviews helped produce good results.

In order to invade the North in 1863, Lee needed reliable information about the route his army would follow. Early in the year, he assigned the preparation of maps for this purpose to Hotchkiss, a Northerner by birth who nevertheless was Gen. Thomas J. “Stonewall” Jackson’s mapmaker. Hotchkiss was ideal for this work because as a youth he had explored Pennsylvania’s Cumberland Valley and western Virginia.

Hotchkiss was a self-taught engineer, yet his talent and resourcefulness made him one of the more productive and better-known Civil War mapmakers. He enhanced the usefulness of his product by reconnoitering the countryside for militarily significant features and compressing large amounts of information onto his maps.

Fortunately, Hotchkiss kept a journal during the war that subsequently was published. This diary of events provides insight into a mapmaker’s mind-set and methodology. The collaboration of Hotchkiss the topographical engineer and Jackson the military commander worked well. Hotchkiss’ perception compensated for Jackson’s difficulty in envisioning the landscape.

James Boswell was another mapmaker who served the Southern cause. Boswell, chief engineer of the Army of Northern Virginia’s 2nd Corps, died from the same friendly fire that mortally wounded his commander, Stonewall Jackson, at Chancellorsville — demonstrating how precarious the life of an engineer could be.

Hotchkiss’ counterpart on the Union side was Robert Knox Sneden in that Sneden left behind a memoir and an extensive collection of wartime sketches. Published posthumously in two volumes, this unique portfolio of about 800 sketches, drawings and maps covering the entire period of the war is testimony to Sneden’s acuity and talent as a chronicler of history in the making.

Like Hotchkiss, Sneden apparently was self-educated before the war as an engineer as well as an architect. He served in the 40th New York Volunteers. From the outset of the war, his commander, Gen. John Sedgwick, put him to work drawing maps and sketching installations.

There were other talented Union mapmakers during the Civil War, some of whom became well-known later in life. Ambrose Bierce was a famous author, and Washington Roebling engineered the Brooklyn Bridge with the assistance of William Henry Paine. Bierce had served in the Western theater as a topographical officer, while Roebling and Paine were engineers with the Army of the Potomac.

Civil War armies employed a variety of techniques to reproduce maps, the most effective being the lithograph. It was impractical for tactical operations, however, because this was a cumbersome process. While in the field, topographical engineers sketched the terrain of a potential battlefield and usually traced copies for the commanding officers.

The legacy of the Civil War’s topographical engineers or mapmakers is the Military Atlas that accompanies the Official Records of the War of the Rebellion, a U.S. War Department publication. The opposing armies relied on the drawings, sketches and maps contained in this volume to guide them during our nation’s long and costly conflict. Earl B. McElfresh based his exceptional work “Maps and Mapmakers of the Civil War” on this publication. His volume pays homage to those who risked or gave their lives so that they could produce accurate maps.

Though mapmakers generally labored behind the scenes, armies depended on their skill and daring to guide them to their destinations safely and swiftly. The quality of their work often meant the difference between victory and defeat.

Thomas J. Ryan is president of the Central Delaware Civil War Round Table.

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