(NEXSTAR) – Facebook has released a new county-by-county map of the United States showing the percentage of people reporting novel coronavirus symptoms.

The project is designed to help policymakers and health researchers forecast potential COVID-19 hot spots, Facebook said.

The data comes from a voluntary survey conducted by Carnegie Mellon University Delphi Research Center that Facebook asks users to take. Facebook says over a million people responded to the survey in the first two weeks.

“Getting accurate county-by-county data from across the United States is challenging, and obtaining such focused data from across the whole world is even harder,” CEO Mark Zuckerberg wrote in a Facebook post. “But with a community of billions of people globally, Facebook can uniquely help researchers and health authorities get the information they need to respond to the outbreak and start planning for the recovery.”

The map allows users to toggle between flu and COVID-19 symptoms. The map can display results by county or by hospital referral regions.