In this video, we see how NOAA’s National Ocean Service is leveraging new technology to complete a task begun long ago: mapping the world’s oceans. The vast majority of nautical charts were predominantly created manually by sailors and cartographers who didn’t have access to the kind of exacting measurements modern imaging tools can provide. As such, there are gaps in the existing charts and areas lacking in details.

Some charts haven’t been updated since the 1880s. Given that storms can shift sandbars and once-deep water may have grown shallower over time, this is not just an academic endeavor—inaccurate charts pose real dangers for sailors. And, of course, there’s the inherent curiosity about what’s what down there.

NOAA’s bringing a range of technologies to the process. They’re using planes and ships to map the deep ocean floor, and for any place that’s too snug or shallow for larger craft, an autonomous surface vehicle, or ASV, is sent in to handle the job. These sled-sized little boats can be controlled remotely, or programmed to map out an area automatically over a period of hours or even days.