Mapping Project Reveals Pre-1906 Quake San Francisco

A unique crowd-sourcing effort is underway in San Francisco to bring century-old city maps to life. So far, about 400 people have helped out the volunteer effort. To see what it's all about, I took a walk with the guerrilla geographers that dreamed up the project.

We start out on the corner of 18th street and Folsom in the Mission District. Michal Migurski and John are my guides. John prefers that we don't use his last name, in order to keep his online persona and real world identity separate.

"That actually looks like it might be the same building," says Migurski. They're looking at a hand-drawn map on their iPad screen, trying to figure out what was in these buildings more than a century ago.

"Oh, saloon," says John. "The number of saloons and the number of breweries on these maps is stunning." We pass by buildings that were home to a trunk factory, a church and a mill in 1905.

"That's how it works. You say ‘hey, that's interesting,' and you start doing research online and suddenly its 4am," John says.

Migurski is with Stamen Design and John runs the blog Burrito Justice. In their spare time, they're trying to revive the 1905 Sanborn Maps, the incredibly detailed fire insurance maps that were drawn just before the 1906 earthquake.

Over 700 of these maps show the businesses and buildings standing then. Many were destroyed by the massive fire that raged after the quake, but some remain today.

"About 20th street, plus or minus a few blocks, is where everything burned down north of here," says John. "With the Mission, it's incredible how much hasn't changed over the past 120 years."

The maps reveal historical oddities, like the railroad line that went right through the Mission. Or businesses that have stayed roughly the same, like mortuaries or transit centers.

"The maps show a lot of horse and buggy shops that hoofed horses and fixed wagons. And you see these places turn into car and automotive shops by the 1950s," says John.

These maps once sat on a library shelf at the San Francisco Public Library, but recently the library partnered with the David Rumsey Map Collection to scan them in high-resolution.

Migurski says new technology means they can be used in the real world again. "I think the new place we're at is that we're all carrying around devices in our pockets that are good enough to do this on."

Since the maps are on separate pages, Migurski and John want to piece them together, so anyone can search. "That overlay is what we're looking for. That ability to type in your present day address and find out that your street was named something else and you live in what used to be a brothel or something," says Migurski.

But with hundreds of maps, it's no simple task. So they built an online tool and asked the public to help them "geo-rectify" the maps. "The tool presents a user with the old map and today's map and they help do a rough positioning of the old map. The street widths are often not to scale, but user can rotate it to match today's satellite map."

So far, almost all the maps have been placed. "We've got a lot of map nerd friends and so it didn't take very long," Migurski says. (Check out the results.)

Migurski says the idea is to connect people to their neighborhoods in a new way. "I think it's that ability to put everything into the same digital space and to be able to wind time forward and wind time backward that really animates me about this," says Migurski.

The Sanborn company created fire insurance maps after the fire as well, which Migurski and John are also interested in digitizing. "It'll be shocking to see once we get the 1915 maps done to compare them," John says.

The stories behind the maps are John's motivation. "It's about context. A hundred years ago there were people running around, going to work and coming home. And you can figure out where they worked and where they lived, where they had their beer and the brewery they drank it from. It gives you context for the neighborhood you live in."