Historical GIS | Cameron Blevins

The County Problem in the West

Posted on November 20, 2013 by Cameron Blevins

Happy GIS Day! Below is a version of a lightning talk I’m giving today at Stanford’s GIS Day.

Historians of the American West have a county problem. It’s primarily one of geographic size: counties in the West are really, really big. A “List of the Largest Counties in the United States” might as well be titled “Counties in the Western United States (and a few others)” – you have to go all the way to #30 before you find one that falls east of the 100th meridian. The problem this poses to historians is that a lot of historical data was captured at a county level, including the U.S. Census.

521px-Map_of_California_highlighting_San_Bernardino_County.svg — San Bernardino County

San Bernardino County is famous for this – the nation’s largest county by geographic area, it includes the densely populated urban sprawl of the greater Los Angeles metropolis along with vast swathes of the uninhabited Mojave Desert. Assigning a single count of anything to San Bernardino county to is to teeter on geographic absurdity. But, for nineteenth-century population counts in the national census, that’s all we’ve got.

Here’s a basic map of population figures from the 1870 census. You can see some general patterns: central California is by far the most heavily populated area, with some moderate settlement around Los Angeles, Portland, Salt Lake City, and Santa Fe. But for anything more detailed, it’s not terribly useful. What if there was a way to get a more fine-grained look at settlement patterns in these gigantic western counties? This is where my work on the postal system comes in. There was a post office in (almost) every nineteenth-century American town. And because the department kept records for all of these offices – the name of the office, its county and state, and the date it was established or discontinued – a post office becomes a useful proxy to study patterns over time and space. I assembled this data for a single year (1871) and then wrote a program to geocode each office, or to identify its location by looking it up in a large database of known place-names. I then supplemented it with the the salaries of postmasters at each office for 1871. From there, I could finally put it all onto a map:

The result is a much more detailed regional geography than that of the U.S. Census. Look at Wyoming in both maps. In 1870, the territory was divided into five giant rectangular counties, all of them containing less than 5,000 people. But its distribution of post offices paints a different picture: rather than vertical units, it consisted largely of a single horizontal stripe along its southern border.

Similarly, our view of Utah changes from a population core of Salt Lake City to a line of settlement running down the center of the territory, with a cluster in the southwestern corner completely obscured in the census map.

Post offices can also reveal transportation patterns: witness the clear skeletal arc of a stage-line that ran from the Oregon/Washington border southeast to Boise, Idaho.

Connections that didn’t mirror the geographic unit of a state or county tended to get lost in the census. One instance of this was the major cross-border corridor running from central Colorado into New Mexico. A map of post offices illustrate its size and shape; the 1870 census map can only gesture vaguely at both.

The following question, of course, should be asked of my (and any) map: what’s missing? Well, for one, a few dozen post offices. This speaks to the challenges of geocoding more than 1,300 historical post offices, many of which might have only been in existence for a single year or two. I used a database of more than 2 million U.S. place-names and wrote a program that tried to account for messy data (spelling variations, altered state or county boundaries, etc.). The program found locations for about 90% of post offices, while the remaining offices I had to locate by hand. Not surprisingly, they were missing from the database for a reason: these post offices were extremely obscure. Finding them entailed searching through county histories, genealogy message boards, and ghost town websites – a process that is simply not scalable beyond a single year. By 1880, the number of post offices in the West had doubled. By 1890, and it doubled again. I could conceivably spend years trying to locate all of these offices. So, what are the implications of incomplete data? Is automated, 90% accuracy “good enough”?

What else is missing? Differentiation. The salary of a postmaster partially addresses this problem, as the department used a formula to determine compensation based partially on the amount of business an office conducted. But it was not perfectly proportional. If it was, the map would be one giant circle covering everything: San Francisco conducted more business than any other office by several orders of magnitude. As it is, the map downplays urban centers while highlighting tiny rural offices. A post office operates in a kind of binary schema: no office, no people (well, at least very few). If there was an office, there were people there. We just don’t know how many. The map isn’t perfect, but it does start to tackle the county problem in the West.

*Note: You can download a CSV file containing post offices, postmaster salaries, and latitude/longitude coordinates here.*

A Dissertation’s Infancy: The Geography of the Post

Posted on August 30, 2012 by Cameron Blevins

A history PhD can be thought of as a collection of overlapping areas: coursework, teaching, qualifying exams, and the dissertation itself. The first three are fairly structured. You have syllabi, reading lists, papers, classes, deadlines. The fourth? Not so much. Once you’re advanced to candidacy there’s a sense of finally being cut loose. Go forth, conquer the archive, and return triumphantly to pen a groundbreaking dissertation. It’s exhilarating, empowering, and also terrifying as hell. I’ve been swimming through the initial research stage of the dissertation for the past several months and thought it would be a good time to articulate what, exactly, I’m trying to find. Note: if you are less interested in American history and more interested in maps and visualizations, I would skip to the end.

The Elevator Speech

I’m studying communications networks in the late nineteenth-century American West by mapping the geography of the U.S. postal system.*

The Elevator-Stuck-Between-Floors Speech

From the end of the Civil War until the end of the nineteenth century the US. Post steadily expanded into a vast communications network that spanned the continent. By the turn of the century the department was one of the largest organizational units in the world. More than 200,000 postmasters, clerks, and carriers were involved in shuttling billions of pounds of material between 75,000 offices at the cost of more than $100 million dollars a year. As a spatial network the post followed a particular geography. And nowhere was this more apparent than in the West, where the region’s miners, ranchers, settlers, and farmers led their lives on the network’s periphery. My dissertation aims to uncover the geography of the post on its western periphery: where it spread, how it operated, and its role in shaping the space and place of the region.

My project rests on the interplay between center and periphery. The postal network hinged on the relationship between its bureaucratic center in Washington, DC and the thousands of communities that constituted the nodes of that network. In the case of the West, this relationship was a contentious one. Departmental bureaucrats found themselves buffeted with demands to reign in ballooning deficits. Yet they were also required by law to provide service to every corner of the country, no matter how expensive. And few regions were costlier than the West, where a sparsely settled population scattered across a huge area was constantly rearranged by the boom-and-bust cycles of the late nineteenth century. From the top-down perspective of the network’s center, providing service in the West was a major headache. From the bottom-up perspective of westerners the post was one of the bedrocks of society. For most, it was the only affordable and accessible form of long-distance communication. In a region marked by transience and instability, local post offices were the main conduits for contact with the wider world. Western communities loudly petitioned their Congressmen and the department for more offices, better post roads, and speedier service. In doing so, they redefined the shape and contours of both the network and the wider geography of the region.

The post offers an important entry point into some of the major forces shaping American society in the late nineteenth century. First, it helped define the role of the federal government. On a day-to-day basis, for many Americans the post was the federal government. Articulating the geographic size and scale of the postal system will offer a corrective to persistent caricatures of the nineteenth-century federal government as weak and decentralized. More specifically, a generation of “New Western” historians have articulated the omnipresent role of the state in the West. Analyzing the relationship between center and periphery through the post’s geography provides a means of mapping the reach of federal power in the region. With the postal system as a proxy for state presence, I can begin to answer questions such as: where and how quickly did the state penetrate the West? How closely did it follow on the heels of settler migration, railroad development, or mining industries? Finally, the post was deeply enmeshed in a system of political patronage, with postmasterships disbursed as spoils of office. What was the relationship between a communications network and the geography of regional and national politics?

Second, the post rested on an often contentious marriage between the public and private spheres. Western agrarian groups upheld the post as a model public monopoly. Nevertheless, private hands guided the system’s day-to-day operations on its periphery. Payments to mail-carrying railroad companies became the department’s single largest expenditure, and it doled out millions of dollars each year to private contractors to carry the mail in rural areas. This private/public marriage came with costs – in the early 1880s, for instance, the department was rocked by corruption scandals when it discovered that rural private contractors had paid kickbacks to department officials in exchange for lavish carrying contracts. How did this uneasy alliance of public and private alter the geography of the network? And how did the department’s need to extend service in the rural West reframe wider debates over monopoly, competition, and the nation’s political economy?

Getting Off The History Elevator

That’s the idea, at least. Rather than delve into even greater detail on historiography or sources, I’ll skip to a topic probably more relevant for readers who aren’t U.S. historians: methodology. Digital tools will be the primary way in which I explore the themes outlined above. Most obviously, I’m going to map the postal network. This entails creating a spatial database of post offices, routes, and timetables. Unsurprisingly, that process will be incredibly labor intensive: scanning and georeferencing postal route maps, or transcribing handwritten microfilmed records into a database of thousands of geocoded offices. But once I’ve constructed the database, there are any number of ways to interrogate it.

To demonstrate, I’ll start with lower-hanging fruit. The Postmaster General issues an annual report providing (among other information) data on how many offices were established and discontinued in each state. These numbers are fairly straightforward to put into a table and throw onto a map. Doing so provides a top-down view of the system from the perspective of a bureaucrat in Washington, D.C. For instance, by looking at the number of post offices discontinued each year it’s possible to see the wrenching reverberations of the Civil War as the postal system struggled to reintegrate southern states into its network in 1867:

Post Offices Discontinued By State, 1867
(Source: Annual Report of the Postmaster General, 1867)

The West, meanwhile, was arguably the system’s most unstable region. As measured by the percentage of its total offices that were either established or discontinued each year, states such as New Mexico, Colorado, and Montana were continually building and dismantling new nodes in the network.

Post Offices Established or Discontinued as a Percentage of Total Post Offices in State, 1882
(Source: Annual Report of the Postmaster General, 1882)

Of course, the broad brush strokes of national, year-by-year data only provide a generalized snapshot of the system. I plan on drilling down to far more detail by charting where and when specific post offices were established and discontinued. This will provide a much more fine-grained (both spatially and temporally) view of how the system evolved. Geographer Derek Watkins has employed exactly this approach:

Screenshot from Derek Watkins, “Posted: U.S. Growth Visualized Through Post Offices” (25 September 2011)

Derek’s map demonstrates the power of data visualization: it is compelling, interactive, and conveys an enormous amount of information far more effectively than text alone. Unfortunately, it also relies on an incomplete dataset. Derek scraped the USPS Postmaster Finder, which the USPS built as a tool for genealogists to look up postmaster ancestors. The USPS historian adds to it on an ad-hoc basis depending on specific requests by genealogists. In a conversation with me, she estimated that it encompasses only 10-15% of post offices, and there is no record of what has been completed and what remains to be done. Derek has, however, created a robust data visualization infrastructure. In a wonderful demonstration of generosity, he has sent me the code behind the visualization. Rather than spending hours duplicating Derek’s design work, I’ll be able to plug my own, more complete, post office data into a beautiful existing interface.

Derek’s generosity brings me back to my ongoing personal commitment to scholarly sharing. I plan on making the dissertation process as open as possible from start to finish. Specifically, the data and information I collect has broad potential for applications beyond my own project. As the backbone of the nation’s communications infrastructure, the postal system provides rich geographic context for any number of other historical inquiries. Cameron Ormsby, a researcher in Stanford’s Spatial History Lab, has already used post office data I collected as a proxy for measuring community development in order to analyze the impact of land speculation and railroad construction in Fresno and Tulare counties.

To kick things off, I’ve posted the state-level data I referenced above on my website as a series of CSV files. I also used Tableau Public to generate a quick-and-dirty way for people to interact with and explore the data in map form. This is an initial step in sharing data and I hope to refine the process as I go. Similarly, I plan on occasionally blogging about the project as it develops. Rather than narrowly focusing on the history of the U.S. Post, my goal (at least for now) is to use my topic as a launchpad to write about broader themes: research and writing advice, discussions of digital methodology, or data and visualization releases.

*By far the most common response I’ve received so far: “Like the Pony Express?” Interestingly, the Pony Express was a temporary experiment that only existed for about eighteen months in 1860-1861. In terms of mail carried, cost, and time in existence, it was a tiny blip within the postal department’s operations. Yet it has come to occupy a lofty position in America’s historical memory and encapsulates a remarkable number of the contradictions and mythologies of the West.

Story of a Thesis, Part 4: Maturation

Posted on August 17, 2008 by Cameron Blevins

(This is the fourth installment of a multi-part post detailing my undergraduate thesis. See part one, part two, and part three.)

As I continued my research into Venture Smith’s life as a free man, GIS allowed me to construct a visual narrative of his forty years in Haddam, CT. After reconstructing each of his real-estate transactions, I was left with a surprisingly nuanced and revealing portrait of a free black man riding the tumultuous waves of Revolutionary and post-Revolutionary New England. In this post I will present a selected sample of some of these recreated transactions, and briefly discuss what they reveal about Smith’s life and the broader world in which he lived.

By 1778, Smith had gone from the owner of a meager ten-acre parcel of low-quality land, to the proprietor of a sprawling 128 acres:

The fifty year-old Smith faced the enviable prospect of having simply too much land to effectively use. Consequently, later that year he sold a twelve-acre tract to two free black men named Whacket and Peter:

In effect, the modest real-estate transaction provided Smith with four additional laborers for his land (Whacket, Peter, and their two wives), while allowing him to recreate a semblance of black communal life in an overwhelmingly white town and region. On several occasions in his narrative, Smith mentions buying the freedom of slaves. In exchange, the men would work under Smith for a period of time. His sale of land to Whacket and Peter marks yet another instance of utilizing black labor, possibly in the tradition of “pawnship,” a West African practice described by Paul Lovejoy and David Richardson. The 1778 real-estate transaction offers a glimpse into both the economic and social motivations of a black man deftly maneuvering within a white world.

Another revealing transaction occurred in 1787, when Smith embarked on a joint business venture with a local man named William Ackley. Smith leased a small island in the nearby Salmon River to Ackley, and in the deed, spelled out with precise detail a contract for the two men to construct a fishing seine on the island. The enterprise was divided equally, with each man supplying half the labor and equipment, including lead, hair for ropes, twine for nets, a boat, and general repairs. In attempting to geographically locate this deed, I turned yet again to GIS. The deed spelled out its locations as “off of Beaver Point.” After finding a nineteenth-century map that labeled Beaver Point, I knew roughly where the island was. Unfortunately, the GIS datasets I had been using didn’t adequately portray the island. This time, I employed aerial photographs of the region in order to locate the island:

As is often the case, GIS offered up as many questions as answers: The island wasn’t entirely contiguous to his property, so how did Smith come to own its leasing rights? Was it a clause within a previous land deed, or was it an entirely separate transaction? I never found answers to these questions, and this investigative process provided me with the valuable (and frustrating) realization of the limits of historical inquiry. Instead, what the transaction did reveal was the phenomenally diverse activities of an independent property owner in the eighteenth-century. Beyond fishing in the river, Smith engaged in prolific woodcutting, tended an orchard, raised livestock, and engaged in trade throughout southern Connecticut and Long Island Sound.

Of course, as with almost any rural inhabitant with a large tract of land, Smith was a farmer. In order to investigate his agricultural pursuits (which both deeds and court files allude to), I looked for farming data I could use in GIS. Fortunately, the US Department of Agriculture created an extensive dataset of soil quality data for the state of Connecticut. I imported this data into GIS and overlaid it onto Smith’s property, creating a precise summary of Smith’s agricultural activity:

Soil Quality Data of Venture Smith's Property - 1790

I filtered the data to isolate only high-quality soil well-suited for farming. Two factors go into this characterization: the slope of the land, and content of the soil. Armed with this information, I found that Smith enjoyed a particularly rich area of farmland in the upper region of his property. I could personally attest to the suitability of this area, as I had walked through it several times:

The land lent Smith with several advantages. It was a short walk to both his homestead and the Salmon River, allowing for easy access, storage, and transportation of goods. In lieu of employing an official currency (which was famously wracked with inflation at the time), Smith, along with much of the rural populace, often utilized goods and produce as a means of exchange. His lucrative pasture provided him and his family with not only sustenance, but a means of obtaining goods with which to participate in the regional economy. As a black man and former slave, his land granted him with a critical foothold within the dominant economic framework of rural New England.

Without GIS, I never would have been able to effectively analyze the relationship between Venture Smith’s freedom and his property. Instead of making abstract conjectures based solely on written primary documents, I was able to add a visual and quantitative element to my investigation. Suddenly I could answer with precise and revealing detail the questions of where, what, how much, and to what degree. I could now recognize patterns, rebuild processes, and craft a visual construction of Smith’s land. With GIS at my fingertips, “ten acres of land” no longer a set of words on a yellowed property deed, but became a deeply nuanced story of where and what the land consisted of, how it reflected and revealed Venture Smith’s motivations and decisions as a free man, and finally his place within the wider world of late eighteenth-century rural New England.

Story of a Thesis, Part 3: Growth

Posted on August 14, 2008 by Cameron Blevins

(This is the third installment of a multi-part post detailing my undergraduate thesis. See part one, part two, and part four.)

When faced with the challenge of exploring the real-estate transactions and land holdings of Venture Smith, I ran up against the methodological barrier of analog technology. Reading the boundary descriptions were not enough. Neither was drawing them out by hand on a piece of paper. I needed the accuracy, fluidity, and versatility of a digital environment. This challenge led me down the path towards GIS, and I introduced myself to Beverly Chomiak, a geology professor at Connecticut College who kindly let me into her computer lab and showed me the basics of the software.

It was overwhelming at first, and the simple polygons I created in the beginning felt a lot like a student driver inching their way around an empty parking lot in a Porsche. I could literally feel the power of the software, as the computer’s hard drive frantically whirred and spun just to boot up the program. But what I was doing with it was almost comically simple. As I grew more comfortable with the interface, I began to explore, and soon hit that eureka moment of placing a series of puzzle pieces together: by creating polygons of neighboring parcels and overlaying them onto a basic map of the general area where I knew his property was located, I could place his first purchase in Haddam:

Once I had those pieces in place, I quickly learned it was a matter of finding data to add to the system. Next up was a hydrography layer, which gave phenomenally detailed information about various bodies of water across the state:

Specifically, this layer revealed something important: Venture Smith’s first purchase in the town, besides being small and narrow, had its eastern portion in a swampy marsh called Dibble’s Creek. Back at Pomona, I enlisted the generous help of Warren Roberts, GIS specialist at the Claremont Colleges’ library. He suggested I look into topography layers, and showed me how to obtain a Digital Elevation Model (DEM) for the region online. DEMs allow the user to minutely examine the elevation and slope of the land, and the regional DEM for Haddam, CT turned out to be exceedingly well-detailed:

Like the hydrography layer, this additional information provided another insight into the quality of his land for that first 1775 purchase: it was incredibly hilly, especially in the eastern portion near the river. Warren also showed me how to create an elevation profile, as if one were walking from west to east across the narrow parcel:

The end conclusion was that this piece of land was not particularly valuable, especially for agriculture: marshy on one end, hilly in the middle, and with a steep bank on the other side. This evidence, supported by a clause within the deed itself, pointed towards Smith using this first parcel of real estate for two purposes: as a spatial placeholder within the town, and as a base of operations for his more lucrative pursuit: cutting timber.

Warren then taught me how to use the DEM data to render a beautiful, shaded effect. Using the elevation data, GIS can create an artificial light source and “raise up” the land to create shadows and highlights. After getting in touch with my artistic background and playing around with transparency, topo lines, and color schemes, I managed to create something that I thought looked pretty good:

While I had spent countless hours examining Smith’s land, both on a computer screen and through on-site exploration, I realized that anyone reading my thesis would have only their imaginations and my flat, two-dimensional maps with which to recreate his property holdings. Fortunately, the seemingly limitless toolkit of GIS allowed me build a 3-D tour of the land through the ever-handy DEM data:

[youtube=http://www.youtube.com/watch?v=iL28FO5WWcQ]

Beyond creating pretty pictures of Smith’s first two property transactions that I could later use as a visual supplement, GIS allowed for in-depth historical analysis of Venture Smith’s real estate. Without this tool, I would have no idea what his first ten-acre purchase actually consisted of. Instead, I knew that it was poor land, and with this knowledge, the technology gave me a glimpse into the motivations and perspective of the middle-aged Smith during those first two years in Haddam. It allowed me to recreate his experience: cutting wood on the side of a hill, moving his timber down the steep embankment and onto the cart path mentioned in the deed, and stockpiling it for transport downriver to a town market center. Using GIS, I knew that these first years were more precarious than Smith let on in his narrative. He faced the daunting prospect of providing for a wife and children, one of whom was a newborn, moving to a new town as black outsiders, and settling onto a narrow strip of land with little to no value. All of this occurred against the backdrop of a quickly-erupting war between the colonies and Great Britain. Armed with the toolkit of GIS and peering through the lens of property and land, I was ready to construct my own narrative of Venture Smith’s life as a free man.

Map of Early Modern London

Posted on August 3, 2008 by Cameron Blevins

I’m glad to see the Map of Early Modern London is getting a fair amount of coverage. Spearheaded by Janelle Jenstad at the University of Victoria, the project “maps the streets, sites, and significant boundaries of late sixteenth-century and early seventeenth-century London. You will see many of the theatres and landmarks of Shakespeare’s time, and learn about the history and culture of the city in which he lived and worked.” In order to do so, they have created two interfaces of the Agas map of London. One is an old-school format of breaking the map into a basic grid with 32 boxes – clicking on one zooms in to that section and shows starred points of interest, such as taverns, theaters, etc. Hovering your mouse over the star gives you the name, and clicking on it takes you to more information about the location. This format is okay, but limited. For someone who has become completely accustomed to GoogleMaps, it is frustrating not having the quick and easy control of zooming in and out, panning, or finding information while remaining “in” the map.

They attempted to address this with an experimental map, which has a much more complex and interactive interface:

This really puts you in the driver’s seat in determining how you want it to appear, maneuvering through the map, and accessing its information. Jenstad designed the project as a pedagogical tool, and I think it would work really well for the classroom. It allows students to find information while also exploring the city and being able to observe geographical patterns or relationships. Interesting assignments could be looking for patterns in establishments, comparing and contrasting different wards and their contents, or designing a “walking tour” based on a theme of their choosing. I wish they would also make it possible to create a mash-up that incorporates present-day multimedia, such as clicking on a location and having a photograph or video appear.

The site does have its share of bugs and problems – broken links, buttons that disappear or don’t do anything, etc. Maneuvering within the map (even the experimental one) still feels kind of clunky. This is a general problem with interactive maps that aren’t based off an already-existing structure (such as GoogleMaps, ArcMap, etc.) Independently created maps can often seem amateur in comparison to standard, powerful formats we are used to utilizing. Nevertheless, I admire the project and the way it was carried out. It is immensely collaborative, with a long list of student contributors, and general guidelines for contributing information and plans to create an editorial board that will use a “refereeing process” of evaluation.

Review: Placing History (III)

Posted on July 29, 2008 by Cameron Blevins

(This is the third installment of my review of Placing History. See the first and the second parts.)

I’ve finally finished Placing History: How Maps, Spatial Data, and GIS are Changing Historical Scholarship. As my previous posts have made clear, I’m quite impressed with the breadth and depth of the compilation. As before, I’ll briefly recount the remaining chapters, and wrap up my thoughts at the end.

“Mapping Husbandry in Concord: GIS as a Tool for Environmental History,” by Brian Donahue. I liked this chapters for a multitude of reasons. On a personal note, his research is quite similar (though wider in scale) to the work I did in mapping property holdings and transactions of Venture Smith. So in a self-congratulatory mood, I found myself nodding with satisfied agreement at his various points about the benefits and drawbacks to mapping land deeds and parcels. On a less personal level, I liked the various angles he took in pursuing his study of Concord – especially examining seemingly disparate holdings of a variety of original families and noting patterns of land use.

“Combining Space and Time: New Potential for Temporal GIS,” by Michael Goodchild. For starters, the cover illustration for this chapter was a piece of Charles Minard’s famous “Carte Figurative,” which depicts a staggering array of geographic, temporal, and statistical information regarding Napoleon’s ill-fated Russian campaign:

Information graphic guru Edward Tufte described it as “the best statistical graphic ever drawn,” which effectively canonized it for any map and information graphic nerd such as myself. This is a roundabout way of saying I was excited to start reading Goodchild’s chapter. Goodchild doesn’t dissapoint, as he uses decades of geography experience to explore ways in which the field is gradually shifting to incorporate temporal data. Although its heavy on technical geography, it’s a rewarding chapter that covers one of the fundamental challenges of historical GIS: how do you visually display the relationship between space and time? Goodchild predicts that this challenge will rapidly diminish, as tools and systems to display things such as dynamic data, or even a history-specific model, will become more and more accessible and widespread.

“New Windows on the Peutinger Map of the Roman World,” by Richard J.A. Talbert and Tom Elliot. Talbert and Elliott present an analysis of the Peutinger Map, a nearly 7 meter long Roman map depicting the Mediterranean world and beyond, constructed around 300 CE:

I liked this chapter a lot, despite my complete unfamiliarity with the subject matter. The authors make compelling arguments backed by GIS analysis, such as: “the basis of the map’s design was not its network of land routes (as has always been assumed) but rather the shorelines and principal rivers and mountain ranges, together with the major settlements marked by pictorial symbols.” They present a quantitative analysis of routes, and utilize a histogram to further examine the segments and their distances.

“History and GIS: Implications for the Discipline,” by David J. Bodenhamer. This chapter, along with the first chapter and conclusion, gives the best “big-picture” perspective on historical GIS. Bodenhamer describes the field of history as a whole, in particular elements of it that relate to spatial analysis. He believes that in order for GIS to become a valuable historical tool, “it must do so within the norms embraced by historians…” GIS is well-situated to do so, because it uses a format of presenting information (the map) that historians are already familiar with, and its visualization and integration of information makes it easier to display the complexity of historical interpretation. He also discusses the challenges to historical GIS. One point I really liked was that technology as a whole, and GIS in particular, often requires a level of precision that historical documents cannot display within “a technology that requires polygons to be closed and points to be fixed by geographical coordinates.” Other challenges range from the theoretical (ex. temporal analysis) to the practical (ex. learning a completely new discipline). Finally, he succinctly sums up one of the greatest challenges: “GIS does not strike many historians as a useful technology because we are not asking questions that allow us to use it profitably.” I could not have said it better myself – until historians begin to ask the type of questions that can be addressed through spatial analysis, GIS will likely remain a technological oddity within the discipline.

“What Could Lee See At Gettysburg?” Anne Kelly Knowles. This is probably one of the most accessible chapters in the book for a layperson. It combines an engaging narrative prose with rich, stylistic maps, and a “popular” subject matter (the Battle of Gettysburg). But more importantly, it clearly presents an answer to a historical question, while contextualizing the issue and presenting possible ideas for future studies. Viewshed (line-of-sight) analysis is of obvious and particular interest to military historians, but it has other implications as well. In particular, this chapter illustrates the phenomenal power of GIS to transport the reader to the past, and get a micro sense of “being” there.

Beyond thoroughly enjoying Placing History, I believe it’s an important contribution to the field of historical methodology in general, and (of course) historical GIS in particular. The compilation gives a wonderful balance while thoroughly exploring the topic: its current state and background, case studies ranging from micro to macro and “hard” to “soft”, discussions on theory and approach, and an outline for the future. I recommend the book to educators, historians, digital humanists, or anyone with even a passing interest in a growing and valuable area of scholarship.

Review: Placing History (II)

Posted on July 19, 2008 by Cameron Blevins

(This is the second installment of my review of Placing History. See the first and the third parts)

I’ve just finished reading about half of Placing History: How Maps, Spatial Data, and GIS are Changing Historical Scholarship, edited by Anne Kelly Knowles. I’ll briefly go through each one, and focus on the ones that particularly interested me.

“Creating a GIS for the History of China,” by Peter K. Bol. Bol, chair of Harvard’s Department of East Asian Languages and Civilizations, discusses his China Historical GIS project. The project attempts to create a basic framework and data source (both spatial and temporal) for geospatial analysis of Chinese history. On a theoretical note, Bol argues that in the case of China, historical GIS should utilize a greater reliance on point data in place of polygons for marking boundaries and territory, in order to better replicate the top-down administrative system of traditional Chinese cartography.

“Teaching With GIS,” by the late Robert Churchill and Amy Hillier. Churchill gives a good overview of the value of GIS in a liberal arts education. I liked his point that one of the benefits of using historical GIS is that any in-depth use of the technology requires an equally in-depth understanding of the problem you’re looking to address. Great point. Because so much of GIS is front-loaded, in that you spend a huge amount of effort in obtaining and managing the data, it requires you to really get your hands dirty in the sources themselves. Hillier gives a lot of great examples of students’ work using historical GIS, mostly Philadelphia-based data. Some of them also included a great 1896 map by W.E.B. Du Bois detailing social class in the city. She also gives some useful tips for educators who want to incorporate GIS.

“Scaling the Dust Bowl,” by Geoff Cunfer. I loved this chapter. Cunfer follows up his previous research in Knowles first book, Past Time, Past Place, by additional analysis of the Dust Bowl. In this chapter, he takes on the common perception of the dust bowl as championed by Donald Worster’s Dust Bowl: The Southern Plains in the 1930’s. While some of Cunfer’s analysis supports Worster, he takes issue with Worster’s commonly-held assertion that the capitalistic over-development of lands for farming the major factor in the fabled 1930’s dust storms. Cunfer first demonstrates through spatial analysis that, although plow-up during the 1920’s did contribute to the Dust Bowl, it was in fact instances of drought that had a much more direct correlation.

He goes on to further his critique of the notion that the Dust Bowl was an extraordinary phenomena caused by human activity. By examining and mapping newspaper accounts of dust storms from the 19th century, along with storms after the 1930’s, he finds that “dust storms are a normal part of southern plains ecology, occurring whenever there are extended dry periods.” Although extensive plowing can enhance the problem, it was not “the sole and simple cause of the Dust Bowl.” Cunfer’s analysis succeeds on many different levels. First, I like the accessibility of it. There’s always a temptation to include too much in the final products, to show off the fruits of your hours and hours of labor. Instead, his maps are clear, uncluttered, and persuasive. Second, I like the way he blended traditionally quantitative analysis tools (GIS) with qualitative historical research (newspaper accounts). He does a good job of highlighting this tension, and aptly warns of its danger, while explaining simply how he accomplished it. Third, his work is a great example of the “right way” to use new technology to both challenge and supplement traditional historical arguments, and in doing so, present an original and different narrative.

“‘A Map is Just a Bad Graph’: Why Spatial Statistics are Important in Historical GIS,” by Ian Gregory. This chapter was much more technical, and included scary words like “regression coefficients” and “heteroscedasticity.” Although statistics in particular, and math in general, is low down on my list of skills, I got a fair amount out of the chapter. I liked his critique of the traditional thematic map, which usually displays one type of data, and with usually one variable involved. Statistical analysis can go beyond simple thematic maps and really open up the powerful underbelly of GIS.

There are several more chapters that I am looking forward to reading and reviewing in a later post.

Review: Placing History (I)

Posted on June 21, 2008 by Cameron Blevins

(This is the first installment of my review of Placing History. See the second and the third parts.)

I finally got around to sitting down with Placing History: How Maps, Spatial Data, and GIS are Changing Historical Scholarship, edited by Anne Kelly Knowles. The book addresses the growing field of combining Geographic Information System (GIS) software with historical scholarship. ((Technical aside: GIS is a broad term for digital analysis of geographic information – most commonly used for making maps – that allows users to input, store, and analyze a huge range of spatial data in a mind-boggling number of ways. Personal aside: I have a been using GIS software for about two years – I employed it extensively in my undergrad research and took a geology class constructed almost entirely around ArcGIS analysis.)) Broken into chapters comprised of individual studies conducted by a variety of scholars, it’s the more modern version of Knowles’s 2002 volume, Past Time, Past Place: GIS for History. The chapters of Placing History range from the quantitatively analytical “Scaling the Dust Bowl” and “Mapping Husbandry in Concord: GIS as a Tool for Environmental History,” to the more big-picture, theory-based “Combining Space and Time: New Potential for Temporal GIS.”

Originally I was planning on finishing all of the chapters before I posted a review of the volume as a whole, but I was too blown away by the introductory chapter of the book, “GIS and History,” written by Knowles. She gives both a wide-ranging and deep analysis of the field. Knowles begins the chapter with the optimistic assertion that, “scholars’ use of geographic information systems (GIS) is changing the practice of history.” From there she gives a brief history of the field, then delves into its current state. I think her greatest accomplishment in this chapter is to balance the obstacles to historical GIS with its huge potential for innovation and scholarship.

On the obstacle end, she writes that one major impediment to historical GIS is the fundamental divide of time vs. space – history is largely a study of subjects within a temporal framework, whereas GIS works largely within a spatial one. And she admits that, “For all practical purposes, historical GIS remains an ad hoc subfield that scholars discover serendipitously.” One reason may be a common complaint of historians concerning geography: that maps are too often seen as stand-alone, objective vessels of information. Instead, Knowles brings up the great point that any serious use of historical GIS requires rigorous examination and discovery of spatial source material, as much as any historian would need to employ in utilizing any diary, letter, or tax record for their research.

Nevertheless, Knowles does a great job of clearly outlining both the advances that have been made and the possibilities for the future. I agree with her basic outlines of the three types of historical GIS currently used:

1. History of land use and spatial economy, ex. outlining agricultural shifts in response to economic or environmental changes.

2. Reconstructing past landscapes, ex. analyzing Robert E. Lee’s line-of-sight (what he could see) during the Battle of Gettysburg.

3. Infrastructure projects, ex. scientists compiling historical landuse datasets in order to track global warming.

In actuality, though, it is nearly impossible to generalize the range of possibilities for historical GIS. The major constraint is really one of imagination and resources – are people aware of all its possibilities, and do they have access to the software/expertise. Finally, she struck a real personal chord in me with her observation that “The most exciting thing about historical GIS is often the ‘eureka’ moment when someone sees data mapped for the first time.” Much like discovering a long-sought after name or date or reference within a manuscript or microfilm, suddenly witnessing your hard work take a physical, visible shape on a computer screen is truly special.

I’m looking forward to reading the rest of the case studies and writing up a brief review, but for a superb introduction to the field of historical GIS, I couldn’t ask for anything better than what Knowles has produced in the opening chapter. At some point I would like to write a post solely dedicated to brainstorming ideas about the ways GIS could be utilized for history in particular and the humanities as a whole, in the vein of PhDinHistory’s blog post, “What I Would Like To See in Text Mining For Historians.”