The maps are then used to legally register the protected boundaries of sites, a kind of landmarking that can be cited in court to prevent development or to punish those who damage ruins by building anyway.

“While various scholars are utilizing drones in their individual investigations, no other country is systematically using drones to manage and protect their sites,” said Lawrence Coben, founder of the Sustainable Preservation Initiative, a nonprofit organization providing economic opportunities to poor communities in which archaeological sites are located. Encroachment has become a particular concern in cities like Lima or Cuzco, near Machu Picchu, the Inca citadel, where land values have risen steadily as the population increases and the economy booms. Many Peruvians were shocked last year when workers using heavy machinery illegally demolished a 4,000-year-old pyramid in Lima to make way for possible development.

“Lima has grown to a point where the only land left is archaeological land,” said Dr. Castillo, who is also a professor at the Pontifical Catholic University of Peru.

Though his work is focused on the deep past, Dr. Castillo is fascinated by gadgets and new technology. He began experimenting with drones about two years ago, buying a $100 one from the Sharper Image. Now he has a squadron of eight, all miniature helicopters that cost about $1,500 to $20,000. He hopes to soon add 20 more.

The drones, he said, “solve the first riddle of archaeology.”

“Finally you can fly whenever you want to, wherever you want to, in any angle, for anything you want and get the great picture you always thought you should take,” he said.