A SZ DJI Technology Phantom 4 drone (top) and a and a Mavic Pro 2 drone fly over palm oil trees at the Genting Tanah Merah Estate, operated by Genting Plantations, in Malaysia. Genting owns about 20 drones, and uses the services of other providers to monitor and map about 160 000 ha of oil palms in Indonesia and Malaysia. Previously, workers walked through dense grass and sometimes hilly terrain to monitor the plantations. The aerial devices use high-resolution cameras that snap thousands of pictures for assembling composite pictures, which are then used to count trees and map estates. Photograph: Joshua Paul for Bloomberg