National Geographic : 1978 Jul
ALL BY CHARLESO'REAR Iapping te canon ESPITE ITS STATUS as the natural attraction Americans most want to see, the heart of the Grand Canyon had nev er been mapped in sufficient detail for confident field use by scientists or hikers. In 1970 Dr. Bradford Washburn, an eminent cartographer and the director of Boston's Museum of Science, decided to remedy the situation. With the joint sup port of his museum and the National Geographic Society, Dr. Washburn began the task that was to take seven years, enlist experts from Arizona to Switzerland, and require nearly 700 helicopter landings on remote sites. Although techniques such as aerial stereographic photog raphy yield most of the detail on the map, precise measure ments must be made on the scene. Atop Dana Butte (left)Dr. Washburn and his wife, Barbara, make one such measure ment. For pinpoint precision, a laser beamed from a far shelf (above) is boomeranged from reflecting prisms in fore ground, recording the distance within centimeters. Rolling a wheel-mounted odometer, two assistants (right) measure trails several times. If the distance does not match within a few feet, the trail is walked again. The result of the work appears as a special supplement to this issue.