Last week I spoke with Joe Bagley, Boston’s city archaeologist about our tool Atlascope and how he uses it to do work that is vital to Boston historical research. In the Atlascope project, we digitally transformed atlases of Boston and its inner suburbs, covering a period from about 1860-1940, in order to line them up with modern day maps of the city. This process involves georeferencing, which basically means we’ve matched points on a historic map and corresponding points on a modern map, so that they can be warped into a format that can be overlaid on a web map. We also had to manually trace the outlines of each oddly-shaped page (or “plate”) of each atlas, so that we could digitally cut them out and stitch them together into a single map. Though this process took thousands of hours, the end result is a much easier and more powerful method for browsing this incredible collection.

A hopefully familiar example for many library users, this is what Atlascope can show! Play around here in this embedded view, or go to the full website.

This tool helps improve access to these materials that are vital to understanding local history and historical geography. So if you have a geography-related research project brewing, check it out! You don’t have to be a professional archaeologist to dig in.

An archaeologist’s evidence

When he begins looking at a property, Bagley needs to prove that he understands what would have been on a site for its entire history, going back to the retreat of the glaciers about 16,000 years ago. To begin his research, Bagley starts with a map:

“It gives me most of the information I need right off the bat. I get the shape of the building over time, I use the atlases to get the owners of the buildings over time too, and that gives me my basic structure to start the deed research, which usually goes back further than the atlases are available. but at least I know I’m on the right house. It eventually connects to all the other owners I have from the atlases. So it really nicely bookends what I need to know. I can check for outbuildings to see if there’s a privy in the backyard, I can look at the changes in the nearby landscape and watch buildings encroach, and basically before I even look up the first person on the site I have a really strong idea of how that place changed over time or didn’t change over time.”

For Bagley, Atlascope is an invaluable tool. “I don’t know how anyone could do what I do in a city that doesn’t have as many digital maps,” he says. “Because I need to literally go owner by owner, property by property back in time and Atlascope is the exact thing that I need to do that.”

Before Atlascope, Bagley would physically come to the Map Center or to the Massachusetts State Library to look at urban atlases of the city. Sometimes, using the physical atlases, which are about two by three feet large (and double the size when they’re open), he couldn’t get a good read on how today’s streets corresponded to yesterday’s. Other times, he simply didn’t have as much data as he does now for a dig. Because these atlases were published by numerous firms, using different titles for different years and parts of the city, it can be difficult to tell from a catalog record alone whether a given volume covers the study area under investigation.

While the streets here have the same names as they did in 1868, they have shifted slightly.

A great example of how georeferenced maps help investigate the process of urban change in Boston is City Square in Charlestown, “where all the streets have the same name and are in vaguely the same place after the Big Dig, but they aren’t,” says Bagley. The streets are “all moved around a little bit. So if you look at the maps you may think you’re in one place based on the orientation of the street, but they were all moved in the 80’s and 90’s. You’re actually in a totally different spot, and the road was 20 or 30 feet over. It’s a fundamentally different space, and you can only get that if you’re using the georeferenced maps because then you can see oh, this has been tweaked a little bit.”

“I don’t necessarily use [Atlascope] as a to-the-inch measurement,” Bagley notes. But for a recent example, the sinkhole in Ronan Park that led to a well, “we knew where the well was, we could put it on the map and do the overlays, and depending on what year map it was, the well was on either side of the property line. And that was really meaningful to our research, because we had to figure out whether the well was the new well that Mary Pierce had to dig as part of the deed that we had documentation for, or if it was the existing well that she had to replace when she bought the property. We still don’t really know the answer, but the fact that it was right on that borderline gave us a much more interesting story and two options that we could kind of explore in the interpretation of that.”

Here, you can see Mary Pierce’s property over modern-day Ronan Park.

One of the most important things that Atlascope can help Bagley determine is whether or not there even is a site to uncover in a particular area.

“There’s been a couple of instances where the site would have been amazing until about 1870 when somebody put a massive brick building on top of it with a clear foundation that took out the really cool archaeological site. That happened recently when I was reviewing what was a florist directly north of Faneuil Hall that’s now Sephora. They were putting utilities in that building and were gonna be trenching and digging around it so I had jurisdiction, and I could have made them do a dig first but I was looking at that property and it would have been exactly where the Old Feather Store was, which is a really important building going back to the 17th century, one of the oldest houses that was standing until the 19th century, when it was torn down.

This map shows the area Bagley is talking about, in fact, immediately after the Old Feather Store was demolished and the property redeveloped.

“But the Bromleys told me that after the building was torn down, every square inch of that property was developed with solid building. So there is no yard anymore, because the yard would have been dug out for all the buildings that came in [after]. It could have been a really cool site if there was an archaeologist working in the late 19th century, but now it’s gone. So [Atlascope] allows me to kind of write off areas quickly and not get too far down the road for research which can take months before a dig. It’s both the thing that allows me to do the research but it also allows me to avoid research into things that are gone.”

This map shows the Scollay Square area, developed so completely that every building touches and there is no yard.

Another nearby example Bagley brought up was Scollay Square, which was razed to build Government Center in the 1960s. Here, 19th century development had so thoroughly transformed the area that there would have been no extant area of pre-19th century yards. Because of this, Bagley could make the informed decision not to dig, knowing that the only sites he had to work with were rubble in mid-20th century basements.

For Bagley, and for anyone doing this type of research, Atlascope saves a lot of time. We do recommend, of course, visiting and conducting research with our collections in person when that’s possible again. But it’s hard to beat with the ease with which you can call up maps on Atlascope and compare different years to one another. Not only can you see the maps easily, legibly, and in very high quality, but you can download high resolution scans with just a few clicks.

Bagley also appreciated our inclusion of other cities and suburbs of Boston in Atlascope—something that’s important to us, too, as a research library that serves not only the city but the broader region. While Bagley is the City Archaeologist for Boston only and doesn’t have jurisdiction to conduct work elsewhere, he recognizes how powerful these maps can be for people in neighboring cities conducting historical research. “That you have the nearby towns also included in this is really incredible,” he told me. “All these other towns are included in the maps which is so helpful. Boston’s the capital of the region, and while it feels like everyone gravitates towards us they also wants to know their story, so I think it’s really nice that you have that data available as well.” Right now, Atlascope covers Newton, Brookline, Cambridge, Somerville, Chelsea, Winthrop, and Revere—but we’re seeking out grant funding that will hopefully help us bring hundreds of more cities and towns from across the state into the project.

In fact, next month, on March 4, we’ll be hosting an event at Cambridge Public Library, Cambridge By Map. We’ll take a dive into local historical geography, and would love for you to join this interactive presentation at lunch time on March 4th. Register here on Eventbrite!

Finally, Bagley pointed out that this is a tool with a lot of future applications. It’s an infrastructure that’s ripe with potential, like providing data that could be used to construct 3D walkthroughs of the North End, tagging historical photographs with geospatial information, or opening up new possibilities of storymapping. We hope you enjoy using Atlascope as much as Joe Bagley, and as always, drop us a line if you’ve got a project you need help on.