writes "PC Pro has a feature revealing how the world's biggest satnav firms create their maps. Nokia's Navteq, for example, has a huge database of almost 24 million miles of road across the globe. For each mile of road there are multiple data points, and for each of those positions, more than 280 road attributes. The maps are generated from public data and driver feedback, not to mention its own fleet of cars with 360-degree cameras on the top. There's an IMU (inertial measurement unit) for monitoring the pitch of the road, and the very latest in 3D surface-scanning technology too. This light detection and ranging (LIDAR) detector captures 1.3 million three-dimensional data points every second, mapping the world around Navteq's field vehicles in true 3D. The feature also investigates whether commercial mapping firms will be replaced by open-source maps."
That last line makes me think of the difference between conventionally published encyclopedias and Wikipedia; "replaced by" is an odd standard in a big marketplace of ideas.