Measuring Trail Erosion with a 35 mm Camera

Abstract

A simple photogrammetric system was designed to monitor trail degradation by generating digital terrain models (DTMs) of sample plots <4m2. A sloped path was photographed in stereo with a standard 35 mm camera from 2.4 m above the ground. A portable stereo camera platform provided the photogrammetric parameters to capture elevation data directly off the photographs with an accuracy of about 3 mm, without the aid of ground control. Volume estimates of simulated trail erosion, computed from the photo-based DTMs, were accurate to about one percent of the true volume.