Apr 11, 2019

A worldwide census from the sky

Mapping buildings from satellite data. Image: Facebook

Using local census data and satellite imagery, Facebook says it has developed a high-definition map of every building in most of Africa, a first step in its plan to plot the entire world's population.

Why it matters: Detailed maps of where people live can help aid workers quickly respond to natural disasters or disease. They're also vital to Facebook's plans to distribute the internet around the world — and, by extension, get more people on the platform.

Details: "Crisis mapping," in which volunteers contribute to maps that relief organizations rely on, has become a popular way to help aid efforts after a disaster.

  • It's usually a manual process that requires contributors to study satellite imagery and add what they see to maps.
  • Facebook today announced a system that automates the process with computer vision. The company is distributing the maps for free, and will use the results for its own internet connectivity projects.

"Facebook’s project is an example of how we'll understand the planet far better with the right data," says Mark Johnson, CEO of Descartes Labs, a startup that uses satellite imagery to track natural resources.

  • Johnson says mapping projects that depend on satellite imagery are changing science.
  • "We're going from sampling a small amount of data and extrapolating [from] it to a world of constant observation, allowing us to have a near real-time understanding of human activity," he tells Axios.

How it works: To figure out where people actually live inside of often-enormous and largely empty census tracts, Facebook engineers started with an algorithm that chucked out every part of the map that clearly didn't have a building in it, based on satellite photos. Then, they used a second AI system to test the remaining 11.5 billion tiles — each covering an area of roughly 100 by 100 feet — for buildings.

Aid workers have used previous versions of Facebook's population maps to deliver electricity to rural Tanzania, or to visit 100,000 houses in Malawi in just three days to tell residents about measles and rubella vaccines.

Go deeper

Axios Dashboard

Keep up with breaking news throughout the day — sign up for our alerts.

What to watch in tonight's Democratic debate

Bernie Sanders at a campaign rally in Colorado. Photo: Helen H. Richardson/MediaNews Group/The Denver Post via Getty Images

Bernie Sanders is now the clear front-runner for the Democratic presidential nomination, and his opponents are ready to try to knock him down at tonight's debate in Charleston, South Carolina — especially Michael Bloomberg, who was the punching bag at the Las Vegas debate.

Why it matters: This is the last debate before Super Tuesday, when Sanders is expected to win California and Texas and could secure an insurmountable lead for the Democratic nomination. That's a direct threat to the entire field, but especially to Bloomberg, who skipped the early states to focus on the March 3 contests.

Bob Iger to step down as CEO of Disney

Photo: Jeff Kravitz/FilmMagic

The Walt Disney Company said Tuesday that it had named longtime Disney executive Bob Chapek as CEO Bob Iger's successor, effectively immediately. Iger will remain executive chairman of the company through 2021.

Why it matters: Iger is credited with having successfully turned around Disney’s animation and studio businesses and with the strategic acquisition of Marvel, Pixar, Lucasfilm and 21st Century Fox. Most recently, he was the person behind Disney's successful launch of its Netflix rival Disney+.

Go deeperArrowUpdated 2 hours ago - Economy & Business