When it comes to maps and geography, Chicago is a tremendously satisfying city: a well-organized grid, easily navigable with minimum coordinates.

"Chicago, you might say, is the Sagres of the American imperium, a hub of geographic and cartographic expertise," wrote Nick Paumgarten in the New Yorker, in a piece about the history of the form. "This is due mainly to Chicago’s role, in the nineteenth century, as a major railroad center."

Underneath that grid, though, is the chaos of the underworld: gas, electricity, water. And it can be dangerous. The most famous example is the Chicago flood of 1992, when miscommunication over the location of an abandoned freight tunnel, among many other things, allowed pilings to be driven into the ground next to it, causing the tunnel to fail and flood much of the Loop.

Smaller incidents happen more frequently. Take June of this year: a construction crew hit a water main in the Gold Coast, forcing residents to boil water; State Street was shut down in two different places, a week apart, after construction crews hit gas lines; a gas main was cut in Hyde Park by an electrical contractor. Around the country, it happens, on average, every 60 seconds.

City Digital, a new collaboration out of UI Labs, aims to ease the process of digging up the city, and perhaps cities throughout the world, by generating a 3D map of its infrastructure.

"The existing way we do this is pencil and paper. If you're a utility, a engineering firm, a design firm, everyone's got various versions of yellowing paper, or in some cases digital drawings of what's down there, and in almost all cases, the accuracy is acceptable within a few feet," says Steve Fifita," executive director of City Digital. "But then you've got the legacy of historical problems. We've run into the old telegraph lines down there, and in some cases wood pipes. You've got things that weren't really documented."

The City Digital database draws from documentation that's available, but adds to it each time a hole is dug for construction. A worker can walk the hole, taking photographs with a smartphone. Like the panorama setting on a phone or digital camera, the City Digital software knits those photographs together, generating a three-dimensional model of the site.

The photo above is an example of how it works. It's a composite of 20 or 30 photographs; the clear overlay in the center is also from a photograph. The fuzziness around them is a 3D dot cloud, which is transformed into an engineering-grade image.

"When you have a top-down 2D version, this is the running-into-assets problem, you didn't see what was below something else," Fifita says. "The other thing is that you're able to gauge depth and congestion. Think about mapping a perfect path. As we're thinking about digging through a congestion of fiber lines, power lines, gas lines, and water lines, having that z-axis, that third dimension, allows us to better map the optimal path."

The software combines existing documentation with the photographs; as the system gets more information, a more accurate map grows. When it comes together, it'll look like this.

"We can bring in the 2D information, but because we're starting with one geolocated, accurate image, as well as a 3D image, through engineering, through good math, through digital mapping, we're then able to digitally draw the rest of the block," Fifita says. "As the process rolls out, as we move past [the] pilot [program], each time a hole is opened up in the city, we go there, we take another image, and then the system learns. The system gets smarter each time there's an open hole. But we're able to stand on the shoulders of the historical information that's available and map that in."

City Digital is a collaboration between the University of Illinois, the City of Chicago, and five companies: Microsoft, ComEd, HBK Engineering, ESRI (which does geographic information systems), CityZenith (which does multidimensional data visualization), and Accenture, the kind of multi-company work UI Labs is intended to bring together. The city gets to use the system for free; the business model is designed for it to be paid for by private firms that could benefit from the data.

"As an example, a construction company that can reduce its time with the digging process, that's real money to them," Fifita says. "A company like that would pay for this information. Design firms, architecture firms, anyone that's in the business of designing, developing, digging, or building. Especially those that have ownership of the assets, like the utilities and the [telecommunication companies]—fiber lines, phone lines, things like that."

The pilot began at Erie and Wabash and will run through the end of the year, generating a three-dimensional map of the entire block. If that works, it could expand well beyond the city. "Post-pilot, our expectation is that we've proven what we call the larger scale," Fifita says, "and then we've got cities like Rome, and London, and New York, and Washington D.C., that are eagerly awaiting our ability to take this to market."