Google’s map offerings build in the human intelligence on the front end, and that’s what allows its computers to tell you the best route from San Francisco to Boston.

In an exclusive story by the Senior Editor at The Atlantic, Alexis C. Madrigal, Google for the first time gives us a look at “Ground Truth”. It is a project described by Madrigal as a secretive, complex internal map that contains data, such as “no-left-turns and freeway on-ramps, speed limits and traffic conditions,” necessary to help users navigate through Google Maps:

I was slated to meet with Gupta and the engineering ringleader on his team, former NASA engineer Michael Weiss-Malik, who’d spent his 20 percent time working on Google Mars, and Nick Volmar, an “operator” who actually massages map data. 

“So you want to make a map,” Weiss-Malik tells me as we sit down in front of a massive monitor. “There are a couple of steps. You acquire data through partners. You do a bunch of engineering on that data to get it into the right format and conflate it with other sources of data, and then you do a bunch of operations, which is what this tool is about, to hand massage the data. And out the other end pops something that is higher quality than the sum of its parts.”

Describing Ground Truth to be an elaborate internal Map Maker of sorts, perhaps the most interesting aspect of the story is just how much human input goes into making the Google Maps experience accurate. In the story, Madrigal noted the Ground Truth Geo team aims to address most of the fixable problems reported by users (thousands daily) within minutes:

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The sheer amount of human effort that goes into Google’s maps is just mind-boggling. Every road that you see slightly askew in the top image has been hand-massaged by a human. The most telling moment for me came when we looked at couple of the several thousand user reports of problems with Google Maps that come in every day. The Geo team tries to address the majority of fixable problems within minutes. One complaint reported that Google did not show a new roundabout that had been built in a rural part of the country. The satellite imagery did not show the change, but a Street View car had recently driven down the street and its tracks showed the new road perfectly.

While breaking down in detail how Google uses the Ground Truth internal map to improve the end-user experience, Madrigal explained the importance of Google’s Street View data going forward:

Google is up to five million miles driven now. Each drive generates two kinds of really useful data for mapping. One is the actual tracks the cars have taken; these are proof-positive that certain routes can be taken. The other are all the photos. And what’s significant about the photographs in Street View is that Google can run algorithms that extract the traffic signs and can even paste them onto the deep map within their Atlas tool. So, for a particularly complicated intersection like this one in downtown San Francisco, that could look like this: (image above)

Google Maps VP Brian McClendon explained further:

“We can actually organize the world’s physical written information if we can OCR it and place it,” McClendon said. “We use that to create our maps right now by extracting street names and addresses, but there is a lot more there…”We already have what we call ‘view codes’ for 6 million businesses and 20 million addresses, where we know exactly what we’re looking at,” McClendon continued. “We’re able to use logo matching and find out where are the Kentucky Fried Chicken signs… We’re able to identify and make a semantic understanding of all the pixels we’ve acquired. That’s fundamental to what we do.”

We recommend swinging by The Atlantic to read the rest of the lengthy post about Google’s Ground Truth program.

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