Crowd-mapping With Cell Phones

Cellular data can reveal where people spend their days

2 min read
Crowd-mapping With Cell Phones
Sources: Ramón Cáceres, James Rowland, Christopher Small, and Simon Urbanek, “Exploring the Use of Urban Greenspace through Cellular Network Activity”; Fabio Manfredini, Paola Pucci, and Paolo Tagliolato, “Deriving Mobility Practices and Patterns from Mobile Phone Data”

To determine the ebb and flow of city dwellers, public officials have typically resorted to looking around and counting. But now censuses can be taken every few milliseconds, as phones ping cellular networks and reveal their location.

For instance, Italian [PDF] and American [PDF] researchers generated usage maps for Milan and the borough of Manhattan in New York City using anonymized cellular data. Paolo Tagliolato, a postdoc at the Polytechnic University of Milan, says such anonymized data are effectively free and always up to date. Conversely, he says, Milan’s last comparable citywide survey was costly, involved 750 000 interviews, and hasn’t been updated since 2002.

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Why the Internet Needs the InterPlanetary File System

Peer-to-peer file sharing would make the Internet far more efficient

12 min read
An illustration of a series
Carl De Torres

When the COVID-19 pandemic erupted in early 2020, the world made an unprecedented shift to remote work. As a precaution, some Internet providers scaled back service levels temporarily, although that probably wasn’t necessary for countries in Asia, Europe, and North America, which were generally able to cope with the surge in demand caused by people teleworking (and binge-watching Netflix). That’s because most of their networks were overprovisioned, with more capacity than they usually need. But in countries without the same level of investment in network infrastructure, the picture was less rosy: Internet service providers (ISPs) in South Africa and Venezuela, for instance, reported significant strain.

But is overprovisioning the only way to ensure resilience? We don’t think so. To understand the alternative approach we’re championing, though, you first need to recall how the Internet works.

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