Automated Digital Photogrammetry: A Valuable Tool for Small-scale Geomorphological Research for the Non-photogrammetrist?

Digital photogrammetry provides a tool with which to automatically generate digital elevation models (DEMs). The necessary equipment is now both readily available and affordable: thus there is considerable potential for this technique to be widely adopted in geomorphological studies. But is it possible for geomorphologists without a background in photogrammety to use it successfully? As part of a larger study into rill initiation by overland flow, a non-metric digital camera and ERDAS IMAGINE OrthoMAX software were used to generate small-scale DEMs of soil surface microtopography. This paper reports on the procedure used, highlights potential pitfalls, and comments on the quality of the resultant DEMs. Whilst acquisition of high-quality images using a digital camera is relatively straightforward, problems were subsequently encountered due to the small size of the internal imager and the need for camera calibration. Potential stumbling blocks in the use of the software lay in the setting-up of ground control points and the use of tie-points and check-points, as well as several software glitches not identified in the current manual. Nonetheless, once these problems were overcome the technique proved to be a simple, effective and fast tool for generating high quality microtopographical DEMs. This methodology shows great promise for future geomorphological studies that require these kinds of surface data.