Flying mathematician

His adventure flights over rough mountains yield stunningly accurate maps. Rick Armstrong is snuggled up with a laptop in the cluttered space that was once the backseat of a six-­ passenger Cessna 206. Twenty-­five hundred meters below, sun-­splashed Portland, Ore., slowly dissolves into the Tolkienesque foothills of Mount Hood. It's some beautiful scenery. But right now, Armstrong's eyes are fixed on his computer, which monitors the images that are streaming in from a camera mounted under the belly of the little plane.