Mark Bergen:

On any given day, there could be a half dozen autonomous cars mapping the same street corner in Silicon Valley. These cars, each from a different company, are all doing the same thing: building high-definition street maps, which may eventually serve as an on-board navigation guide for driverless vehicles.
 These companies converge where the law and weather are welcoming—or where they can get the most attention. For example, a flock of mapping vehicles congregates every year in the vicinity of the CES technology trade show, a hot spot for self-driving feats. “There probably have been 50 companies that mapped Las Vegas simply to do a CES drive,” said Chris McNally, an analyst with Evercore ISI. “It’s such a waste of resources.”
 Autonomous cars require powerful sensors to see and advanced software to think. They especially need up-to-the-minute maps of every conceivable roadway to move. Whoever owns the most detailed and expansive version of these maps that vehicles read will own an asset that could be worth billions.
 Which is how you get an all-out mapping war, with dozens of contenders entering into a dizzying array of alliances and burning tens of millions of investment dollars in pursuit of a massive payoff that could be years away. Alphabet Inc.’s Google emerged years ago as the winner in consumer digital maps, which human drivers use to evade rush-hour traffic or find a restaurant. Google won by blanketing the globe with its street-mapping cars and with software expertise that couldn’t be matched by navigation companies, automakers and even Apple Inc. Nobody wants to let Google win again.
 The companies working on maps for autonomous vehicles are taking two different approaches. One aims to create complete high-definition maps that will let the driverless cars of the future navigate all on their own; another creates maps piece-by-piece, using sensors in today’s vehicles that will allow cars to gradually automate more and more parts of driving.