Imagine Big Brother but just for buildings.

Amber Surrency, a former intelligence analyst in the Marines who is now an aerial research photographer for CoStar, looks for dirt piles, partial foundations and other clues that suggest construction.

CoStar flies a small Cessna Grand Caravan around the country to find developments to add to its commercial real estate database. It then sells the information to brokers and other subscribers.

CoStar researchers make thousands of calls to developers, property owners and other real estate professionals, It also canvasses neighborhoods via car, but the company finds 50 percent more properties from the sky, Surrency said.

“Really the best way to get the most information and the most accurate information is to go and see it for ourselves,” she said.

Earlier this month, Surrency and two pilots spent four days, or about 10 flight hours, surveying the Twin Cities area. Taking off from Flying Cloud Airport in Eden Prairie, the crew last week climbed into the small plane on the hunt for properties during a one-hour flight demonstration. The plane passed over Shakopee, circled an industrial complex being built in Cottage Grove and then soared above St. Paul.

From a control panel in the cockpit, Surrency can operate a cinematographic camera mounted on the bottom of the plane. Assisted by datapoints from CoStar’s system, the team scans the area and points out possible new properties. Once a new location is found, the plane circles the site to make a high-resolution video. Later, stills are taken from the video and the data will be sent to CoStar staff to do additional research.

While drones have become popular to use in the real estate industry, they wouldn’t be as efficient as the CoStar aircraft, Surrency said. Drones wouldn’t usually be able to be powered as long or travel as far, she said.

CoStar bought its plane in 2014, and originally intended for the research collected during the flights to add to data for its top markets but it has expanded the flights to canvass 136 markets about once a year. According to CoStar, their researchers are able to update their databases within three hours instead of the eight days it had taken before the company bought the aircraft.