San Francisco International Airport spans over 5,000 acres, with 18 million square feet of indoor space across 97 buildings, serving more than 42 million passengers last year.

To keep the facility running smoothly, the airport’s managers rely on a digital twin—a three-dimensional virtual replica of the airport that is continuously updated with data gathered from embedded sensors or other connected devices throughout the airport. Thanks to the data, the digital twin changes with its physical counterpart in real time, making it a useful tool for studying performance, running simulations and making predictions about the physical asset it mirrors.

The airport’s operator, a department of the city of San Francisco, started to bring all the data about the airport into a centralized digital twin in 2014. Although data sources are still being added to the virtual model, the technology already is helping the airport run better, according to Geoff Neumayr, the airport’s chief resiliency and sustainability officer.