By Christopher Brockman

Anne Kelly Knowles, editor of the first text connecting historical scholarship and GIS technology entitled Past Time, Past Place: GIS for History, suggests that each case study of this foundational work illustrates “how geographic information and GIS technology can facilitate historical inquiry.”[1] Historical technologists like Knowles refute the common interpretation of GIS as a supplement to historical narrative or a clever illustration of traditional archival research. Knowles definition of GIS itself suggests the broad capacity for bold research:

A geographic informational system (GIS) digitally links locations and their attributes so that they can be analyzed, whether by their geographical characteristics, such as location, distance, proximity, density, and dispersal, or by their attributes, such as social, economic, and physical characteristics.[2]

Like many facets of the digital humanities, GIS does not fit neatly into the written mode of academia, often the standard vehicle for historical scholarship. When the intellectual processes that build a traditional written narrative are combined with GIS, the historical argument is demonstrated via a balance of written text and visual media: a variety of interpretative content that not only advances an argument, but may allow the user to mold the question. David Bodenheimer, one editor of Deep Maps and Spatial Narratives, argues for the use of GIS technology to rework traditional narrative structures around data of time and place:

The real question is not the definition of spatial narrative but how to tap digital and spatial technologies to move narrative beyond the linear constraints of written language into a more fluid and reflective process in which we can see and experience change and development as a way of understanding an event or place more fully.[3]

Given the wave of new technological media for exploring historical questions and expressing their answers, historians must pay close attention to the scholarly perspectives that frame the questions themselves, a focus commonly described as historiography. Typically historiographic questions are answered by considering the body of literature available that addresses a particular topic. Questions with narrow perspectives are limited to the number of historiographic lenses one employs to investigate the question, whereas broader questions consider many different kinds of lenses. For instance, an investigation into the decline of the construction industry during the Great Depression would surely focus on economically based lenses, whereas the causes of the Great Depression in general includes all sorts of lenses ranging from politics to economic to social interactions. GIS provides additional lenses by which scholars can attack historiographical questions independent of the narrative but not divorced from it: taking the strengths of traditional scholarship and adding nonlinear features that approach historical unknowns from entirely new angles. Like the foundational text Past Time, Past Place, the best way to explore these new historiographic lens is via case studies, a structure that will be used here. Groundbreaking GIS systems equip historians with several new lenses for historical inquiry, as deep mapping, geo-spatial indexing, and the recreation of historical environments provide opportunities to pursue new research questions or approach traditional historiographical problems from a new angle.

While most can appreciate the geographic nature surrounding a GIS project, few can discern how GIS compares to an enhanced historical map. Part of the problem lies with scholars employing GIS who do not make such a distinction: digital historians that practice GIS not only avoid creating an exclusive definition, but also seem to employ “GIS” and “historical mapping” interchangeably. For the purposes of this essay, GIS is defined as the ability to create a digital map from a database of information–a project that uses carefully categorized information to develop a product driven by historical question. Thus, GIS is a fusion of statistical information demonstrating historical significance, the interconnection of this information with chosen coordinates plotted on a map, and the driving scholarly question behind both data sets. In comparison, historical maps are missing the database component–critical pieces of historical information are assigned to a place without a categorization in a database structure. Still, both initiatives are driven to address a particular historical question or questions, allowing them to stand alone from the monograph as historical scholarship. GIS, however, allows for unprecedented depth into statistical patterns, new perspective on geographic relationships with historical concepts, and instructive graphical user interfaces that bring historical scholarship into an entirely new realm.

Deep Mapping

The first lens digital historians might consider is deep mapping, or the use of GIS to ascribe tremendous detail into the multimedia illustration of a location. Likely the most comprehensive lens, deep mapping can be defined as a “finely detailed, multimedia depiction of a place and the people, animals, and objects that exist within it and are thus inseparable from the contours of everyday life.”[4] This lens provides innovative looks into communities that have been studied previously without the depth or interactivity provided by GIS systems. Such studies go to the heart of GIS: using digital databases to explore a community with unprecedented depth.

The Valley of the Shadow was groundbreaking for a list of reasons, one of which included the project’s implementation of deep mapping. While the interface to these deep maps may appear stale, the innovative research applied to the project continues to inspire digital humanists in GIS feature implementation. According to Aaron Sheehan-Dean in “Similarity and Difference in the Antebellum North and South,” the project’s research team looked to answer a key historical question: how different were the two counties when separated by the Civil War?[5] GIS linked databases allowed researchers to geographically examine social and economic factors that are frequently used to illustrate the differences between antebellum northern and southern communities. In this way, the Roads and Railroads, 1860 graphic suggests both counties had developed networks of roads and railroad lines, complete with a hub towards the middle of each country. The Franklin and Augusta: Towns graphic makes clear the existence of towns within six miles in both counties, attacking the myth that the antebellum South was significantly more rural than the North. Sheehan-Dean adds to this analysis, suggesting that both northern and southern towns contained social organizations and economic networks. Finally, Sheehan-Dean employs the Franklin and Augusta Soil Quality graphic to argue that the southern elite did not dominate the parceling of land for agricultural use as strongly as the political arena, as both counties displayed a fairly egalitarian land distribution.[6] (Figure 1) Sheehan-Dean concludes that the data makes a comparison between the two communities much more involved than originally believed, a socioeconomic comparison that would not have been possible without deep mapping.

Franklin and Augusta County - Soil Quality

Figure 1 – Franklin and Augusta Soil Quality – Aaron Sheehan-Dean, “Similarity and Difference in the Antebellum South” in Past Time, Past Place: GIS for History

A second groundbreaking project in deep mapping addresses the famed Salem Witch Trials, providing an equally impressive array of materials to investigate the seventeenth century village. Like The Valley of the Shadow, The Salem Witchcraft GIS also addressed a key historical question: what motivated the key players in Salem to act the way they did? Co-creator of the GIS project Benjamin Ray specifically considered the validity of Paul Boyer and Steven Nissenbaum’s explanation in Salem Possessed, a monograph that explained Salem’s hysteria according to social and economic factors. Ray’s “Teaching the Salem Witch Trials” discusses how the GIS project (Animated Figure #1) tested Boyer and Nissenbaum’s theory, and added complexity to the historiographical understanding of the trials. According to Ray, a central component to Salem Possessed is its division of the village into two halves: the accusers to the west and the accused and their defenders to the east. Ray and his team plotted tax rates and church membership records, and did not find a pattern to explain the hysteria. In addition, the GIS used primary records to identify the locations of participants on either side, validating the division Boyer and Nissenbaum identified. However, the project stands as more than just an evaluation tool. By plotting the participants and their tax bracket, Ray and his team were able to confirm that accusers were far more likely to originate from the upper class, further reinforcing Boyer and Nissenbaum’s work.[7] Perhaps most importantly, the GIS project provides a tremendous resource for future study: clicking on the icon connected to an accused resident launches a separate page, providing documents, photographs, and additional analysis. While paling in comparison to the detail provided in The Valley of the Shadow and other contemporary projects, Salem Witchcraft GIS provides a critical example for deep mapping and the potential to connect artifacts, people, and places in spatial terms.

CTB - Animated Figure #1

Animated Figure #1 – Salem GIS

Deep mapping continues to expand from the strong foundation these early projects constructed. Worthy Martin explains two such contemporary projects in “Warp and Weft on the Loom of Lat/Long,” an exploration of four case studies that model the significance of deep mapping for social and cultural historical investigation. The digitization of Homer’s Iliad provides a “temporal progression” of the play similar to the timelines seen within The Valley of the Shadow and The Salem Witchcraft GIS, as the user can connect lines of the poem with the actions on stage.[8] In addition, this digitization project entitled Homer’s Trojan Theater allows users of the site to examine the spatial relationships between characters in the play.[9] A second deep mapping project examined by Martin is the Chaco Research Archive (Animated Figure #2), a digitization project that assigns spatial data to Native American artifacts excavated from Chaco Canyon, New Mexico.   The archive produces an incredibly artistic yet academically practical interface, allowing users to explore the Canyon site to find artifacts, or search a list of artifacts that will connect back to their dig location. Either way, the user is connected to the artifacts and their location, providing in-depth special analysis of the excavation artifacts virtually.[10] What sets these deep mapping projects apart from other digital maps is their ability to accept user queries to manipulate the information. From using The Valley of the Shadow archive to the compare the social dynamics of two communities to exploring Chaco Canyon to make sense of archeological findings, deep maps provide a powerful lens to access the details of a location in a virtual environment.

CTB - Animated Figure #3

Animation Figure #2 – Chaco Research Archive

 Geo-Spatial Indexing

There does not appear to be a term designated for the opposite approach to deep mapping, where sources, not places, take center stage. If deep maps attempt to focus the projects’ energy on acquiring a detailed view of the place, what term should be used when the focus is on assigning a spatial address to a data set? This is entirely a different approach–instead of attempting to understand a place by applying detailed data, the purpose is to understand the data set by applying GIS locations for analysis. There must be a term designated for this framework, as a tremendous amount of projects are data focused, as opposed to location centered. This essay will employ the combined term “geo-spatial indexing” for this purpose, as the objective of these projects is to organize (or index) data according to its geographic or spatial origin or association.[11] On the surface this seems like a backward approach, but GIS must be used to understand data which has geographic or spatial components as much as it creates a detailed view of a given place or space. A strong series of examples of geo-spatial indexing are seen in projects depicting depression era America, a time in which politicians and academics alike looked to decipher the causes of the crisis using both economic and social frameworks–agendas that accumulated tremendous socioeconomic data.

The housing industry quickly emerged within the depression era as a key section of American socioeconomic life paralyzed by the spiraling economic situation. Contemporary historians have examined this data from a racial perspective, looking to determine if Franklin Roosevelt’s New Deal attacked the housing crisis to benefit all races. Historian Kenneth Jackson’s added a tremendous resource to this area of scholarship after discovering maps developed by the Home Owners Loan Corporation (HOLC) that graded urban real estate, a discovery he employed in his milestone work Crabgrass Frontier: The Suburbanization of the United States (1987). This work argued that HOLC’s mapping project influenced lenders and the Federal Housing Administration (FHA), creating a redlining experience that made homeownership more difficult for minority groups. Several accomplished historians have expanded upon Jackson’s work, an endorsement Amy Hillier tested using GIS technology connected to HOLC and general real estate data in a project entitled Redlining in Philadelphia.[12] Hillier employed GIS indexing to three hundred HOLC loans in Philadelphia, and did not find a correlation between socioeconomic status and loan awards. Next, Hillier choose a random sampling of private loans and used the same GIS indexing as HOLC loans, coming to the same conclusion–redlining did not appear to be a factor, and the loans were scattered throughout all of the graded areas, even those with low ratings.[13] (Figure 2) Hillier does not suggest that New Deal agencies are without fault, as HOLC and later FHA maps certainly influenced the distribution of mortgage insurance and helped to set interest rates, but  believes historians have placed far too much emphasis on HOLC maps.[14] Hiller’s Redlining in Philadelphia makes a bold statement, both historiographical and technologically via an efficient use of GIS.

 Radomized Loans                        HOLC Loans

Figure 2 – Home Owner’s Loan Corporation Loans in Philadelphia (Left) and Random Citywide Sample of Mortgages made by Private Lenders in Philadelphia (Right) –  Amy Hillier, “Redlining in Philadelphia” in Past Time, Past Place: GIS for History

A second key theme of the Great Depression was agricultural migration in the face of the ecological disaster known as the Dust Bowl. Like Amy Hillier’s work, Geoff Cunfer sought to evaluate a historiographical argument in his essay “Scaling the Dust Bowl,” which cites Donald Worster’s Dust Bowl: The Southern Plains in the 1930’s as an authoritative source on the Dust Bowl itself. Cunfer’s extraordinary GIS work evaluates Worster’s central claim, that capitalism drove farmers to overuse their land in order to make ends meet, essentially destroying the plains in the process.   GIS is used incredibly effectively in pursuit of agricultural reality: did agricultural habits contribute to the Dust Bowl?[15] Cunfer employed GIS to graphically display environmental factors as one layer and instances of dust storms as an overlay, which at first confirmed over-plowing using agricultural land use maps and the documented locations of dust storms.[16] However, a GIS inspired drought map, which logged the shifting rates of rainfall over five year periods, provides much more leverage in explaining the instances of dust storms in the Midwest. (Figure 3) Cunfer was also able to effectively debunk the exceptionality of the depression era dust storms by employing GIS to index observations of dust storms throughout the later third of the nineteenth century.[17] Confer’s study is an excellent example of a traditional historical question that should be revisited with GIS: historians writing before such technology became available were not able to view source material through this new lens, all the more reason for their use in today’s academy.

Percent Difference

Figure 3 – Percent differences from average rainfall for five-year periods preceding dust seasons, 1932-1940.

George Cunfer, “Scaling the Dust Bowl” in Placing History: How Maps, Spatial Data and GIS Are Changing Historical Scholarship

The growth of GIS technology, coupled with the growing complexity of the Internet, has given birth to geo-spatial indexing projects so complex that users can query databases to find resources that will support their own claims. Photogrammar (Animated Figure #3), a database of the legendary Farm Security Administration’s documentary photographs, provides users the ability to view photographs via their tagged geographic location, tagged subject area, or eventually by particular regions of the country. This site permits users to study specific photographers or particular themes of the depression, and then consider a spatial analysis of their selected resources. Just as groundbreaking, Social Explorer indexes incredible amounts of data from the United States Census dating back to its first instance in the eighteenth century. Social Explorer allows users to customize the visualization of their selected data, save the maps themselves, and even “tell a story” with the GIS inspired maps they have created. Interactivity is the future of historical GIS: not only using the database to make a scholarly argument, but to create the project in such a way that it will assist others in their research as well.

CTB - Animated Figure #2

Animated Figure #3

Recreation of Historical Environments

Blending the focus on geographic locations within deep mapping with the strategy of focusing on particular data sets provides historians with a third lens of historical inquiry: recreation of historical environments. This framework focuses less on layering data to provide clarity to a data set or a detailed account of a place and instead uses GIS databases to recreate a lost area. The goal is to use a particular section of data to recreate one aspect of the historical place, perhaps layering these environments to build a more complete depiction of the historical area. In this way, the focus is not to learn everything about the location, as the project typically focuses on a narrow stretch of time, but also limits in the scope of the data sets to what historical angles the project pursues.

Brian Donahue’s study of husbandry and agricultural method in seventeenth century Massachusetts entitled “Mapping Husbandry in Concord: GIS tool for Environmental History” stands as a perfect example of using GIS to recreate a historical environment. While Donahue’s work does provide tremendous detail in its depiction of Concord, it is limited in scope by agricultural data–aiming only to explore the significance of the villages’ agricultural systems. Most importantly, Donahue’s work also addresses a historical question: should the reputation of farmers in colonial New England as unskilled, unproductive, and agriculturally destructive continue as they have been historically portrayed?[18] Donahue indexed the harvesting patterns of Concord farmers, suggesting that villagers “mowed” more hay than their English counterparts would have, perhaps indicating an intentional structuring of the agricultural process.[19] Donahue’s study of property lines is even more telling, as the GIS indexing of second generation landowners revealed an apportioning of strong timber lots among several different owners to as not to monopolize one specific section.[20] Finally, GIS recreation of landowner’s plots in Concord reveal a sophisticated subdivision of plots in order to add family members to the system, a parceling that provided separate plots but did not collapse the agricultural structure.[21] In the end, Donahue makes a convincing argument for Concord residents as capable farmers in system that lacked efficiency but was not economically bankrupt, a case made by recreating Concord agricultural patterns with GIS.

Struggles Threatening the Survival of GIS

While these projects represent the tremendous potential available via GIS technology, they also embody pitfalls that may prove fatal to these lenses of inquiry. First, while historical scholarship continually works against the temptation to be consumed by a local case study, the natural fit for specific data sets within GIS databases enhances the potential for historians to become lost at the local level and forego national implications. While the comparisons between Franklin and Augusta counties in The Valley of the Shadow are impressive and convincing, do these observations hold up if a city in the Deep South were chosen? When examining Amy Hillier’s research methods in Redlining Philadelphia, is a sample size of three hundred loans inclusive enough, especially when the GIS database has the capacity to layer multiple indexes to see how the loan data evolves over time? If a project is going to hold up under national criticism, it must consider the potential for critique due to a narrow focus. Secondly, visualizations must be updated to incorporate new developments in technology. The Valley of the Shadows databases are close to flawless, but the GIS implementation could be made more dynamic by embedding content in the frame of the map instead of taking the user to a separate page. Even the strongest of projects must be updated to avoid a decline in use simply because of stale icons and rigid navigation menus. Finally and most importantly, this technology must live and be consistently available on the Web. Some projects contain online companions but leave crucial pieces of the project unavailable, as Hillier’s Redlining Philadelphia includes an interesting digitization of a classic Philadelphia real estate map linked to HOLC documents that document property in the given zone, but GIS maps of mortgages scattered throughout the city (a central part to her argument) are completely missing. Worse still, the only access to Geoff Cunfer’s brilliant GIS analysis connected to “Scaling of the Dustbowl” comes in the form of a CD in the back of Placing History. If GIS is going to be a leading framework within the emerging field of digital history, then leading projects must employ the now standard techniques of the digital humanities.

Graveyarding and the Future of GIS

As these projects have demonstrated, GIS can produce groundbreaking scholarship outside of the traditional research format. However, these lenses of historical inquiry must make key changes if they are to continue down this path. Projects relegated to “yesterday’s digital history” must continue to evolve and grow, or else the GIS and the rest of digital histories forfeit the one clear advantage they have control over the published monograph: ability to easily be updated. If this is not modeled with previously successful projects historians will continue to see digital projects as monographs on a screen, less than a living, interactive depiction of historical scholarship. ‘Graveyarding’ might be used to describe this process–an effort to bring online projects that have previously lived on hard drives and intranets as well as the alteration of a project’s visualization of GIS data that has gone stale. A final step GIS must take is to bring this technology into the hands of undergraduate history students, either in the form of coursework in higher education institutions or to develop web based products that will allow users to create their own projects. While the power of software such as ArcGIS is clear, GIS technology is being passed over by young, technology savvy historians who do not have days to learn how to use particular types of software. Even in a limited form, a web based application for GIS would provide an avenue for the technology to grow, building a more solid reputation for strong scholarship in the field of history without the traditional research model in tow.

______________________

[1] Anne Kelly Knowles, “Introducing Historical GIS,” in Past Time, Past Place: GIS for History, ed. Anne Kelly Knowles (Redlands, California: ESRI Press, 2002), xi.

[2] Knowles, xiv.

[3] David Bodenheimer, “Narrating Space and Place” in Deep Maps and Spatial Narratives, ed. David Bodenheimer, John Corrigan, and Trevor Harris (Bloomington, Indiana: Indiana University Press, 2015), 20-21.

[4] David Bodenheimer, John Corrigan, and Trevor Harris, ed., Deep Maps and Spatial Narratives (Bloomington, Indiana: Indiana University Press, 2015), 3.

[5] Aaron Sheehan-Dean, “Similarity and Difference in the Antebellum North and South,” in Past Time, Past Place: GIS for History, ed. Anne Kelly Knowles (Redlands, California: ESRI Press, 2002), 36.

[6] Sheehan-Dean, 38-43. It is important to note that the “Franklin and Augusta Soil Quality” graphic is unavailable on the Valley of Shadow website as of June 27, 2015.

[7] Benjamin Ray, “Teaching the Salem Witch Trials” in Past Time, Past Place: GIS for History, ed. Anne Kelly Knowles (Redlands, California: ESRI Press, 2002), 22-26.

[8] Worthy Martin, “Warp and Weft on the Loom of Lat/Long,” in Deep Maps and Spatial Narratives, ed. David Bodenheimer, John Corrigan, and Trevor Harris (Bloomington, Indiana: Indiana University Press, 2015), 218-219. The Valley of the Shadow and The Salem Witchcraft GIS are two of the four projects explored by Martin.

[9] Martin, 220.

[10] Martin, 213-217.

[11] This is not to be confused with the application command “Geo-Spatial Index,” which has a technical origin in GIS programming.

[12] Amy Hillier, “Relining in Philadelphia” in Past Time, Past Place: GIS for History, ed. Anne Kelly Knowles (Redlands, California: ESRI Press, 2002), 82, 85.

[13] Hillier, 85, 87.

[14] Hillier, 87-89.

[15] George Cunfer, “Scaling the Dust Bowl” in Placing History: How Maps, Spatial Data and GIS Are Changing Historical Scholarship, ed. Anne Kelly Knowles (Redlands, California, ESRI Press, 2008), 100.

[16] Cunfer, 106-107.

[17] Cunfer, 108, 115-116.

[18] Brian Donahue, “Mapping Husbandry in Concord: GIS tool for Environmental History” in Placing History: How Maps, Spatial Data and GIS Are Changing Historical Scholarship, ed. Anne Kelly Knowles (Redlands, California, ESRI Press, 2008), 152-153.

[19] Donahue, 160.

[20] Donahue, 162.

[21] Donahue, 166-169.

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