Fire insurance maps are an invaluable resource for anyone trying to understand how cities have changed over the past century. The challenge has always been unlocking what's inside them—that is, until the Chicago Urban Heritage Project came online.
Founded and led by Parker Otto, AB'24, the ambitious project at the University of Chicago is turning high-resolution scans of early 20th century Sanborn Atlases into clickable, searchable digital maps. With the help of undergraduate researchers, the project is bringing the history of the city’s neighborhoods to life.
“Our work is impacting communities, changing narratives and educating people about their places," said Otto. "I love doing this research, we’re helping people realize that we can learn from how things used to be to build a better future.”
The project is an initiative of the Chicago Studies program in close collaboration with the UChicago Library’s Center for Digital Scholarship. Students comb through city record archives and use tools such as QGIS software to digitize building footprints and organize spatial data. They also learn to explore historical questions through large, complex datasets.
The Sanborn company began producing its finely detailed atlases in the 1860s to help insurance firms assess fire risk in cities across the United States. Today, they offer a rich record of the construction, location, use and purpose of buildings in historic Chicago.
“The Sanborn maps offer a window into a very particular period of a neighborhood’s history,” said Chris Skrable, executive director of Chicago Studies & Experiential Learning and assistant dean of the College.
When complete, the project’s interactive online maps will offer urban scholars a comprehensive new tool to digitally explore how the residential, commercial and environmental landscape of the city has changed over the past century.
Mapping beyond Hyde Park and Woodlawn
The Urban Heritage Project grew from the Chicago Centuries Project, an initiative that studied the evolution of the neighborhoods around UChicago’s campus, with a focus on the 55th and 63rd Street corridors between 1920 and 2020.
Student researchers collected data about every building on each neighborhood block and used Sanborn maps and historic aerial photos to digitally represent their findings, decade by decade.
Initially, they did their digital mapping by hand—a painstakingly long and tedious process. Only after the team had drawn and georeferenced accurate building footprints could they layer contextual data about the buildings onto the map.
As the project progressed, it became clear that the volume of historic data was quickly outpacing the mapping team’s capacity.
“I thought, ‘There has to be a faster way,’” said Otto, who was then a third-year environmental and urban studies major working on the 63rd Street project.
Taking on the challenge, he experimented with a machine-learning workflow and wrote his own Python code to speed up the work. It was an effort that Skrable said “became an obsession.”
That obsession paid off. Now, instead of tracing every building corner by hand, researchers deploy Otto’s code to identify buildings in the high-resolution scans and turn them into building-footprint polygons that import directly into QGIS. The process reduces the time needed to create full-resolution footprints.
After graduating, Otto became the inaugural Herbert Zar Post-Baccalaureate Fellow in GIS at the UChicago Library's Center for Digital Scholarship. Due to the fellowship, Otto was able to focus significant time on the project, allowing him to make substantial progress and map the remaining neighborhoods. He worked with GIS librarian Rob Shepard to refine the computational workflow and underlying code to make it faster and more reliable.
Using his new workflow, Otto mapped the neighborhoods needed to represent the Chicago Centuries Project data. Then, he posed a question to Skrable: “What if we just kept going?”
That question became the foundation of the Chicago Urban Heritage Project, shifting the work from a corridor-based study to a citywide research effort.
A cohort model for undergraduate research
The Chicago Urban Heritage Project launched with its first cohort of undergraduate researchers last spring.
Otto, now a master’s student in the University of Pennsylvania’s urban planning program, continues to lead the project from Philadelphia. As a graduate research coordinator for the Chicago Studies Program, he hires, trains and supervises a cohort of undergraduate researchers who work alongside him to map Chicago.
Sophia Liu, a second-year public policy major, found her way to the project through the Chicago Studies newsletter. Growing up in New York City nurtured her fascination with how cities evolve and how physical spaces can shape history.
When she arrived at UChicago, she wanted to engage deeply with the city. The project’s blend of a technical approach with archival research only deepened its appeal.
“I just thought that the idea of looking at old insurance maps was really cool,” she said.
Liu interviewed to join the inaugural research cohort, led by Otto—“this young guy in his twenties.”
“It was inspiring to me that undergraduate students were conceptualizing these research ideas,” Liu said, noting that the current cohort is diverse in majors, backgrounds and perspectives but united by curiosity and “a shared interest in the history of Chicago.”
Fellow researcher Griggs Fuller, a second-year public policy major with a GIS minor, described himself as “really into cities and urban planning” and was energized by the opportunity to contribute to an active research project in Chicago.
Liu, Fuller and their fellow researchers began working on the project with Otto and Skrable last spring. Otto trained and mentored the new research group on campus until the end of his fellowship, and Fuller and Liu have since taken new leadership roles as undergraduate supervisors.
Working closely with Otto, they support recruitment and hiring, manage training, oversee research workflows and lead weekly meetings with the cohort. Students also rely on a shared Slack channel, where questions about coding, historical content or mapping decisions can be answered in real time.
“The joke with the cohort is that I never sleep,” Otto said. “Students reach out to me at 3 a.m. and I’ll respond in like five seconds!”
For Liu, that culture of collaborative learning is a defining feature of the project.
“You don’t need to have all the skills to start,” she said. “It’s really accessible, and a learning experience for everyone.”
From the archives to real-world impact
For urban scholars, Sanborn fire insurance maps are “an incredibly valuable data source,” Skrable said.
But finding complete, high-quality sets can be difficult, especially for persons not connected to an academic institution. And the analog nature of the historic images is an obstacle to their being analyzed with contemporary questions in mind. By digitizing map sheets for the entire city, the Chicago Urban Heritage Project is making these materials more accessible for and useful to a new generation of researchers.
When students aren’t digitizing, they might be tracking down additional Sanborn maps in places such as the Chicago Public Library, the Chicago History Museum and the Library of Congress.
“They can be found in odd places,” Liu said. “I think we found a couple on a website called OldInsuranceMaps.net.”
Fuller recalled encountering Sanborn images in an out-of-print book from the University Library’s GIS Collection.
“I think Parker also has a picture of one that we can’t find anywhere else,” he said—possibly, rumor has it, from a local collector with a large private Sanborn archive.
Students georeference each scanned sheet by matching points on the historic map to intersections on a modern map of Chicago. After a sheet is accurately aligned, students run Otto’s Python model to extract building outlines and convert them into digital polygons, after which Liu and Fuller guide the cohort through reviewing and cleaning the results. New researchers learn the workflow in introductory training sessions, followed by hands-on practice and regular feedback.
The resulting data is already being shared with the public. The team developed a website, with initial design assistance from Taylor Faires and Shepard, that allows users to explore every map with multiple overlays and filters, making the Sanborn maps an even richer, consolidated resource for Chicagoans to learn from.
“The website was a really cool way that we were able to take the existing data and make it more interactive,” Fuller said.
Liu said the team wants to make it easier for researchers to do archival research.
“This kind of dataset just doesn’t exist right now,” Liu said. “We also want the website to be accessible to people who are simply curious about historical maps of Chicago and want to understand how their neighborhoods have changed over time.”
The work has already supported research projects in areas ranging from environmental justice to transit-oriented development.
“These research projects are fundamentally intended as educational opportunities for students,” Skrable said. “The goal is to teach students that these resources are out there, and to give them hands-on, mentored experience in working with them.”
—A version of this story is published on the University of Chicago College website.
