AppleInsider looks at how online maps (Apple Maps, Google Maps), especially their traffic layer, inadvertently revealed Russian troop movements at the start of the Russian invasion of Ukraine.

The sheer volume of mapping data now available at our fingertips means it was possible for civilians half a world away to see when Russian forces began moving. Specifically, that data pinpointed a traffic jam starting on the Russian side of the border, actively moving into Ukraine in the first few minutes of the Russian and Ukraine conflict.

Just as with any cartography, this information required interpreting. Google Maps did not specifically say that it was troop movements, nor was its satellite imagery up to the minute. During the process of researching this story, we’ve confirmed that Apple Maps presented similar inbound troop movement information—but it wasn’t setting out to do that either.

What these services did, though, was register all of the smartphone users whose driving was slowed or halted by unusual traffic conditions. Wherever the majority of the data came from, it was possible to determine what was happening when coupled with known details of Russian troop locations.