NASA needs help taking pictures of trees. The space agency’s ICESat-2 satellite estimates the height of trees from space, and NASA has created a new tool for citizen scientists that can help check those measurements from the ground. All it takes is a smartphone, the app, an optional tape measure, and a tree.
NASA recently added a new feature to its public GLOBE Observer app called GLOBE Trees that allows people to measure trees on the ground using their smartphone. To do so, users take their smartphone and stand 25 to 75 feet away from a tree. They hold the phone in front of their face and aim the camera first at the base of the tree and then at its top. To complete the process users take a picture, count their steps to the tree and log their position. The app then uses all of this information to determine the tree’s height, which NASA can compare to its own data to see if its satellite is correct.