A GIS-Based Model for
Battlefield Preservation Planning

 

 
 
 

William J. Drummond 
City Planning Program 
College of Architecture 
Georgia Institute of Technology 
Atlanta, GA 30332-0155 

Voice:

(404) 894-9840

Fax:

(404) 894-1628

Email:

bill.drummond@arch.gatech.edu


 

I. Introduction


The movement to preserve Civil War battlefields began as a citizen-led grass roots movement. It initially focussed upon the creation and maintenance of cemeteries near major battlefields, then gradually extended into the battlefields themselves. Groups of individual veterans would purchase small plots of land upon a battlefield then erect monuments marking the location of their units' heaviest fighting. Then during the decade of the 1890's Daniel E. Sickles (who lost a leg at Gettysburg) and other veterans in Congress successfully fought to establish the first four national military parks at Chickamauga and Chattanooga, Shiloh, Gettysburg, and Vicksburg. Since that time the federal government has played the major role in acquiring and preserving Civil War battlefields (Linenthal 1991, pp. 87- 126).

Over the last twenty years, however, much of the initiative for new battlefield preservation efforts has come from a public-private coalition involving groups such as the Conservation Fund (http://www.conservationfund.org), Civil War Trust (http://www.civilwar.org), and Association for the Preservation of Civil War Sites (http://www.apcws.com). These groups raise private funds for the purchase or protection of of endangered battlefield land, then donate the acreage to the state or federal government.

In 1986 a large mixed-use development development was proposed and approved for land adjacent to the Manassas Battlefield National Park (Boge and Boge 1993). This land, though privately owned, was the scene of significant events in the battle of Second Manassas, and the resulting uproar lead to (a) the federal government's purchase of the land (for over $100 million), (b) creation, in 1991, of the federal Civil War Sites Advisory Commission and (c) establishment of the American Battlefield Protection Program, located in the National Parks Service. The Commission published its findings in 1993 (CWSAC 1993), and this report remains the single most important document for Civil War battlefield preservation.  The full report is available on the World Wide Web at http://www2.cr.nps.gov/abpp/cwsac/cws0-1.html.

The Commission members distinguished 384 principal battles from among the 10,000 separate skirmishes, actions, combats, and battles of the war. They then assessed each of the 384 battlefields with regard to historical significance, current integrity, area under protection, and anticipated threat from development. By combining information from these four categories, the Commission members classified each battlefield into four classes of preservation priority. The highest priority class includes 50 battlefields with critical needs for immediate coordinated action. Priority classes II, III, and IV identify, respectively, battlefields with comprehensive preservation opportunities, those needing added protection, and those battlefields that are so fragmented or developed that preservation that extensive preservation is impossible (CWSAC 1993, pp. 41, 49-53). The report of the Commission also identified the preferred roles of federal, state, and local governments in future preservation efforts. Among the recommended roles for local government planners are

The purpose of this paper is to describe how geographic information system (GIS) technology can and should play a central role in these efforts and to detail how a GIS-based planning model can assist in the complex difficult work of battlefield preservation planning. Section II of this paper will survey the major battlefield preservation roles for GIS while section III will focus on a GIS-based model for battlefield preservation planning. In section IV this model is applied to the Lost Mountain-Brushy Mountain Line located in a rapidly developing area of Cobb County, Georgia about 12 miles northwest of downtown Atlanta, Georgia.
 

II. Multiple roles for GIS in battlefield preservation


Given the potential roles for local government in battlefield preservation, it is clear that GIS can play a number of vital roles. These roles can be arranged into four major groups: inventory, management, interpretation, and planning. The first two, inventory and management, are largely internal to government. The last two, interpretation and planning, involve government officials, extra-government interest groups, and individual citizens.

The inventory task involves the collection, documentation, and publication of information about the battlefield. The Civil War Sites Advisory Commission initiated this process with the creation of basic battlefield maps for all 384 principal battles. The maps were drafted on U.S.G.S. topographic sheets by historians from the National Park Service as well as other local experts. They include troop positions, sites of significant structures and surviving entrenchments, and designated "core areas" (where significant fighting took place) and "study areas" (the larger setting of the battles). Although some information from some of these maps has been digitized, the great majority of the data exists only on the physical map sheets. Each state historical preservation agency received two sets of these maps for its state, and complete sets exist only in the National Archives and at the offices American Battlefield Protection Program. At present there are no plans to create a GIS version of this invaluable resource (Gossett 1998).

At the local level, the task of creating GIS inventories of battlefield resources has been greatly eased by the spread of Global Positioning Systems (GPS) technology. GPS receivers use a constellation of Department of Defense satellites to calculate the receiver's latitude and longitude. Spatial accuracy within 50 to 100 meters can be accomplished by even the most inexpensive receivers, and with more sophisticated equipment accuracies of one to five meters can be gained. GPS enables historic and cultural resources to be spatially catalogued without the need for expensive surveying. The Cultural Resources GIS unit of the National Parks Service has pioneered the use of GPS technology for battlefield preservation and provided introduction training for many federal, state, and local government employees (http://www2.cr.nps.gov/gis/).

The management task utilizes GIS for the day-to-day management of the battlefield and its surrounding areas. This task involves many elements that are not unique to battlefields. Any organization administering a large land area will find GIS useful for the management of roads, infrastructure, facilities, and natural resources.

Other elements of the management task, though, may be characteristic only for battlefields. Once a battlefield preservation plan has been developed, the local government's GIS can be used to implement and monitor the plan. This can include providing an early warning system of land transactions in the battlefield area, notifying state or federal officials of impending development, and coordinating local, state, and federal responsibilities for battlefield preservation.

The interpretation task involves description, explanation, and illustration of the historical events that took place on the battlefield. At most battlefields this is done through some combination of printed maps, publications, displays, electric maps, artifact collections, interpretive markers, and sound recordings.

In at least three ways GIS presents new opportunities for interpretation. First, on the battlefield itself the amount of mounted interpretive materials is severely limited by the need for maintaining the integrity of the historic landscape. GIS can allow virtually unlimited interpretive materials to be keyed to specific battlefield locations, then presented through kiosk displays or Internet sites on the World Wide Web. These GIS-based materials can include an enormous range of visual and text items such as photographs, paintings, etchings, soldier letters, journal entries, after-battle reports, and battle orders.

Second, GIS can be used to record battlefield troop locations without physically marking the battlefield itself. GIS is now being utilized at several battlefields to create regimental-level troop maps, with the first published example coming from the Fredericksburg battlefield (O'Reilly 1997). GIS-based troop maps can be used to print physical maps, but they can also be electronically linked to other databases. For example, the National Park Service is creating a searchable database of the names and units of every Civil War soldier and sailor (http://www.itd.nps.gov/cwss/). Once this database is complete it will be possible to link it to a GIS dataset of battlefield troop locations. It will then be possible display to the actual battlefield positions for the unit of any individual soldier. Over three million soldiers fought in the Civil War, and tens of millions of Americans are descended from those soldiers. GIS technology can provide the missing link so that descendants of Civil War soldiers can identify the specific places where their ancestors fought and sometimes died.

Third, GIS can be used as an important tool in the creation and implementation of battlefield-related heritage tourism programs. Heritage tourism is becoming an increasingly

important area for economic development, especially in rural areas (Kennedy and Porter 1994). There were over 10,000 instances of various levels of fighting during Civil War, and the great majority of these have not been actively preserved or commemorated with historical markers. GIS can record the locations of these often obscure actions, then link them together for . Current heritage tourism initiatives like Virginia's Civil War Trails program (http://www.civilwar-va.com/) use traditional printed maps to mark specific tours. With GIS potential tourists will use the Internet to search a cultural resources database, select specific locations, create a custom itinerary, then receive driving directions, custom maps, and suggested lodgings, restaurants, and other tourism-related businesses.

The planning task, the last of the four GIS roles for battlefield preservation, will be addressed in detail in the following section of the paper.
 

III. GIS for battlefield planning


GIS technology was initially developed during the 1970s in response to a fundamental question repeatedly encountered in the fields of landscape architecture and urban planning: what types of development are suitable and unsuitable for which areas of land? Answering this question usually involves specifying the locational factors (slope, highway access) required for each type of development, then mapping those factors as a series of layers for the entire study area. The information in the layers would then be overlaid to identify suitable and unsuitable area. This method, now known as land suitability analysis, was initially developed by Ian McHarg (McHarg 1969) then rigorously formalized by Lewis Hopkins (Hopkins 1977). Before GIS was available the individual layers would drawn on transparent sheets and physically overlaid. With GIS the locational factors could be digitized into separate layers then electronically overlaid to produce a new layer in which each small polygon was formed by the the intersections of the polygons in all the factor layers.

GIS-based battlefield preservation planning can be viewed as a special case of land suitability analysis. The GIS is used to collect certain layers of information about the battlefield area, then the layers are combined to find the locations of highest preservation priority, and the most appropriate methods for preserving them.

Although there are a large number of potential factors for consideration, this paper proposes a minimum of five factors that any battlefield preservation plan must include. Four of these factors are directly derived from the work of the Civil War Sites Advisory Commission: significance, integrity, protection level, and threat. These are the same factors that the Commission used to characterize and prioritize the 384 principal battlefields (CWSAC 1993, pp. 49-53). The Commission, however, gave each battlefield a single overall rating for each factor. To develop a plan at the battlefield level each factor must be mapped to show its variation over space. The fifth proposed factor will be land (or easement) acquisition cost.

The first four factors together demonstrate the desirability of preserving any individual portion of the battlefield. Of paramount priority will be areas with great military significance, high integrity, poor protection, and immediate threat. Lowest priority will be those areas that are highly fragmented and have poor or lost integrity. Between these extremes tradeoffs will be need to be made between the various factors. One approach to such tradeoffs can be inferred from the fourteen different priority subcategories developed by the CWSAC.

Table 1 shows the Commission factor ratings and preservation priority classes. The ratings for core protection, battlefield integrity, and development threat are self- evident. The military significance ratings are "A" for a battles with a direct impact on the course of the war, "B" for battles with a decisive impact on their campaign, "C" for battles having an observable influence on a campaign, and "D" for battles affecting important local objectives. 

Table 1
Civil War Sites Advisory Commission
Battlefield Preservation Priority Factors
 
Preservation          Military      Core        Battlefield Dvmt.  Number of
Priority              Significance  Protection  Integrity   Threat   Battles
_______________________________________________________________________________
 
I.1                   A             Under 20%   Good/Fair   High/mod.     11
I.2                   A             Over 20%    Good/Fair   High/mod.      9
I.3                   B             Unspecified Good/Fair   High/mod.     30
 
II.1                  A             Under 20%   Good/Fair   Low            2
II.2                  B             Under 20%   Good/Fair   Low           22
II.3                  C             Unspecified Good/Fair   High/mod.     35
II.4                  D             Unspecified Good/Fair   High/mod.     19
 
III.1                 A             Over 20%    Good/Fair   Low           11
III.2                 B             Over 20%    Good/Fair   Low           12
III.3                 C             Unspecified Good/Fair   Low           50
III.4                 D             Unspecified Good/Fair   Low           32
 
IV.1                  All           N/A         Poor        N/A           64
IV.2                  All           N/A         Lost        N/A           71
_______________________________________________________________________________

The following set of rules, though never explicitly stated in the Commission's report, apparently describe the prioritization of the 384 battlefields.

These rules are somewhat complex due to the fact that in some circumstances interactions between the factors can determine the priority ranking. For example military significance and the level development threat interact so that a higher level of development threat can "promote" a battlefield of lower military significance into class II, while a more significant battlefield but less threatened battlefield is left in class III. Such interactions mean that these priorities could not be calculated from a ratings scheme that assigned points for each category within a factor, mathematically weighted each factor, then summed the results for each battlefield. In other words, the factors are not logically independent of one another, so many of the classic land suitability ratings methods could not be applied.

As discussed above, the Civil War Sites Advisory Commission applied these factors (except for cost) only to the aggregate battlefield, giving each battlefield a single rating on each factor. The same factors can also be applied within each battlefield by using one or more GIS layers for each factor. The spatial variation within the battlefield distinguishes in detail between those areas with greater and lesser significance, higher or lower integrity, better or worse protection, immediate or distant development threat, and higher or lower acquisition cost. These spatial variations can then be used to determine preservation priorities, then preservation plans, and finally implementation policies. The application of five factors within the individual battlefield will now be considered, beginning with significance.

Significance, at the local battlefield level, can be initial defined by following the basic approach taken by the Advisory Commission. Of highest, or "A," significance are areas where fighting took place crucial to the outcome of the battle. Areas of "B" significance include other areas of fighting and bloodshed. Areas of "C" significance would include camps, routes of march, defensive fortifications, and headquarters locations where fighting did not take place, but important support activities did occur. Some areas may have a higher significance if especially interesting or extraordinary events took place there such as the death of a prominent general, the engagement of African-American troops, or the setting for an important literary account such as an Ambrose Bierce short story or Stephen Crane's The Red Badge of Courage. The major sources for this information include primary and secondary historical materials. The Advisory Commission battlefield maps provide a good starting point for this data layer. Supplemental information may be available from the Atlas to Accompany the Official Records of the War of the Rebellion.

Integrity is directly related to the level of modern development. Areas that are fully developed have lost integrity, and areas with only small areas of remaining open land have poor integrity. Fair integrity refers to locations that may preserve a significant portion of the Civil War landscape, but may be marred by traffic, noise, or development within the areas viewshed. High integrity areas preserve both the landscape and setting of the Civil War era. Integrity classification can also be applied to buildings, fortifications, entrenchments, and roads that date from the Civil War era. Integrity data can be derived from a detailed land use map or local government GIS database, a GIS parcel database with land use information, U.S.G.S. topographic maps, and recent aerial photography.

Level of protection is concerned with ownership and development restrictions on each portion of the battlefield. The highest level of protection is achieved by public ownership of land and public commitment to preservation of that land. Good protection can also be achieved by restrictions on development tied to easements or preferential taxation. Protection information is best obtained from local land ownership records, which may be available from the local government as a GIS database.

Level of threat considers the probability that the area will be developed (direct threat), as well as the probability that development elsewhere will have a significant impact on the battlefield (indirect threat). Indirect threats can include development within area's viewshed and increased commuter traffic through the battlefield due to nearby residential development. Sources of threat data may include zoning maps, zoning by parcel, and urban models of population and employment growth.

Last, the cost layer estimates the acquisition costs for purchasing the land or establishing development restrictions through easements or other mechanisms. Property tax assessments will be one major source for cost information, but this source should probably be supplemented with recent sales information for all parcels surrounding and nearby the battlefield.

Information for the integrity, protection, threat, and cost layers can all be generated from one common source: a GIS parcel database with parcel attributes such as ownership, zoning, assessed value, and recent sale information. In nearly all states this data is available only from the local government having jurisdiction over the battlefield area. This fact highlights the importance of maintaining a two-way interchange of information between the federal, state, local or private organization managing the battlefield, and the local governments in the area. Those managing the battlefield should provide the local governments with data on battlefield significance and preservation priorities, while the local governments need to supply information on the status of parcels within the battlefield's area of interest.
 

IV. The Lost Mountain Line


Maps 1 to 8 show the results of applying this method to battles involving the Lost Mountain-Brushy Mountain-Mud Creek line, about nineteen miles northwest of downtown Atlanta, Georgia. This battle was chosen because in at least two dozen places there remain significant entrenchments from the conflict. However, the area is rapidly changing from one of scattered residential subdivisions and occasional commercial centers to a solid mass of suburban development. A recent study by E.D.A.W. funded by the American Battlefield Protection Program generated several basic GIS layers, including the locations of the original line and locations of surviving earthworks.

Unfortunately a parcel-level GIS database is not available for this area, so other more general measures must be used to estimate threat level and acquisition cost. Since none of this land is publicly owned (except for road rights-of-way) the entire area is unprotected.

By June 1864 William Sherman's 100,000 man army had repeatedly outflanked Joesph Johnston's 60,000 man army and forced the Confederates to withdraw from one fortified position to another. Sherman's soldiers had covered about three quarters of the distance from Chattanooga, Tennessee, their starting point, to Atlanta, their destination. Johnston was now behind a strongly fortified line stretching from Brushy Mountain, in the northeast, to Lost Mountain, eight miles to the southwest. Map 1 shows the location of these lines in central Cobb County, Georgia, and their relationship to downtown Atlanta.

On June 14th and 15th Sherman attacked the center of the line at Pine Mountain and Gilgal Church, forcing Johnston to swing back the left half of his line and re-form it along Mud Creek. From June 16th to June 18th Sherman attacked the southern most portion of the line, at Mud Creek, then the center of the line at Latimer Farm. Johnston crept away on the night of June 18th and occupied a new line of fortifications upon and around Kennesaw Mountain (Castel 1992, pp. 270-285). Map 2, using information scanned from William Scaife's Civil War Atlas, shows the troop positions for the Confederate lines and Union attacks (Scaife 1997). An enlarged version showing more detail in Map 2 is also available.  Map 3 displays the positions of the original Confederate fortifications, the core areas in which fighting took place, and the larger study area. The core and study areas are drawn from the Advisory Commission maps for the battles.

The Advisory Commission classified these battles as rating a "B" level of military significance: their impact was potentially decisive for the Atlanta Campaign. The Commission also found that the battlefield was highly fragmented, had poor integrity, and therefore it was placed in priority Class IV.1, the next to the lowest of the fourteen classes. As Map 4 illustrates, there are still very substantial sections of remaining earthworks. In most places where the ground is high and there are no roads the fortifications still survive. Although the Commission's overall integrity rating of "poor" is certainly justified, many individual sections of the line are well preserved.

These sections, though, are threatened by the rapid growth taking place in northern and western Cobb County. The Atlanta Regional Commission publishes census tract population projections. As shown in Map 5, the tract containing the northeasternmost portion of the line will grow from 0 to 100 percent, the majority of the line is in an area of 100 to 200 percent predicted growth, and the southernmost area will grow 300 to 400 percent. In general, the southeastern portion of the line is the most threatened, and the northeastern part the least.

The fifth factor, acquisition cost, has been estimated by the median value of housing in each 1990 Census blockgroup. The orange areas in Map 6 are the most expensive, while the purple areas the least expensive.

When the four factors of significance, integrity, threat, and cost are combined through a GIS overlay process, the result is Map 7. This map shows the existing entrenchments in core areas where substantial fighting took place, and it color codes those trenches based on estimated acquisition cost, with orange ones at higher cost and purple ones at lower cost. Information on development threat was not directly incorporated since the Census tracts are too large to provide spatial detailed information. Instead, all other things being equal, we will prefer to preserve areas in the south and west, to those in the north and east.

Of the fourteen segments shown on Map 7, one appears to be a fairly clear first choice for preservation. This is the long section of light-colored entrenchment near the center of the map. This segment is about 0.3 miles long, lies within the core area of the Latimer Farm attack of June 18th, sits within a blockgroup with median housing value in the $90,000 to $120,000 range, and is found near the end of the line with the highest projected growth rate.

Map 8 shows much more detailed information about this site running from northeast to southwest just west of Ridgeway Road. An image version of the U.S.G.S. topographic map (called a digital raster graphic, or DRG) is superimposed over a scanned aerial photograph (called a digital orthophoto quarter quad, or DOQQ). The contour lines from the DRG show that the entrenchments line upon the high ground connection three hilltops. The DOQQ and DRG both show that the area is undeveloped except for the single house at the southwestern end. The DOQQ indicates that there are no trees in the area, and several faint white lines just to the west of the green entrenchment vector could possibly be the entrenchments themselves.

In conclusion, this paper has developed and applied a GIS-based methodology for battlefield preservation planning. The method began with the four criteria developed the Civil War Sites Advisory Commission and applied to the battlefield as a whole. To these four criteria, significance, integrity, protection, and threat, a fifth cost criterion was added.

The resulting criteria were then applied to the spatial variation within an individual battlefield as individual layers in a GIS. When the criteria are spatially overlaid, the areas of highest and lowest preservation priority can be identified. The GIS model can also be used to make explicit or implicit tradeoffs between the criteria in areas that are neither clearly high or low in priority.

The model was applied to the Lost Mountain-Pine Mountain-Brushy Mountain Line in Cobb County, Georgia. The greatest weakness with this analysis was the lack of a GIS parcel database. Instead, 1990 Census blockgroup data and census tract level population projections were substituted, with mixed success.

The analysis was successful in producing one clear, top, candidate for preservation near Ridgeway Road. When this area was examined with detailed GIS-based aerial photography and raster graphics from the topographic map, its basic suitability was confirmed. The next step would be to examine the county's traditional paper parcel maps, contact the property owners, and conduct a visual ground survey. GIS models such as the one proposed in this paper will never be accurate enough or reliable enough to make actual decisions, but they can serve to steer decision makers to the best opportunities and quickly eliminate the worst choices. This allows decision makers to concentrate their time and expertise in those areas where they have the highest probability of being rewarded.
 

References

Boge, Georgie and Margie Holder Boge. 1993. Paving over the Past; A History and Guide to Civil War Battlefield Preservation. Island Press, Washington D.C.

Castel, Albert. 1992. Decision in the West; The Atlanta Campaign of 1864. University Press of Kansas, Lawrence Kansas.

Civil War Sites Advisory Commission (CWSAC). 1993. Report on the Nation's Battlefields. National Park Service, Washington D.C.

Gossett, Tanya. 1998. Personal telephone interview, February 16, 1998. American Battlefield Protection Program, Washington, D.C.

Hopkins, Lewis D. 1977. "Methods for Generating Land Suitability Maps: A Comparative Evaluation." Journal of the American Institute for Planners. 43(4): 368-400.

Kelly, Dennis. 1990. Kennesaw Mountain and the Atlanta Campaign. Kennesaw Mountain Historical Association, Marietta, Georgia.

Kennedy, Frances H. and Douglas R. Porter. 1994. Dollars and Sense of Battlefield Preservation; The Economic Benefits of Protecting Civil War Battlefields. The Preservation Press, Washington D.C.

Linenthal, Edward Tabor. 1991. Sacred Ground; Americans and Their Battlefields. University of Illinois Press, Chicago, Illinois.

McHarg, Ian L. 1969. Design with Nature. Natural History Press, Garden City, New York.

O' Reilly, Frank. 1997. "Fredericksburg Troop Maps." Eastern National, Fredericksburg, Virginia.

Scaife, William R. 1997. Civil War Atlas and Order of Battle. Civil War Publications, Cartersville, Georgia.