Comparative assessment of analytical and digital photogrammetric methods in the construction of DEMs of geomorphological forms

Abstract

Traditionally, landforms have been measured using a combination of field survey techniques and analogue and analytical photogrammetry. With advances in computing power digital photogrammetric solutions are now seen as offering an affordable and cost effective way of mapping topographic features. This paper looks at the relative merits of each of these photogrammetric techniques, in terms of the practical considerations involved in data extraction and accuracies that can be achieved for a case study. The site investigated is Maiden Castle, situated southwest of Dorchester in Dorset, UK. This paper examines the relative accuracies of both digital and analytical photogrammetric techniques in relation to ground control points recorded using a global positioning system (GPS). Colour stereoscopic aerial photographs were taken of Maiden Castle, Dorset, in November 1999 at a scale of approximately 1 : 4000. Stereo models were constructed using pre-marked ground control points positioned using post-processed differential GPS. Subsequent analysis involved the calculation of residual values produced by comparing the computer-generated surface with a set of test points measured using differential GPS. This research demonstrates that the optimal digital system matched the performance of analytical photogrammetry for the collection of geomorphological data.

Historical aerial photographs for landslide assessment: two case histories

“…A sequence of photographs captures morphological change, which can be unlocked by using appropriate photogrammetric methods. Recent advances in information technology have led to the development of automated digital photogrammetric techniques, allowing for rapid and cost-effective data collection (Chandler 1999;Baily et al 2003). Hence, the aerial photographic archive offers great potential for studying landslide evolution.…”

Topographic structure from motion: a new development in photogrammetric measurement

“…Despite the range of available methods, the production of high resolution, high quality digital elevation models (DEMs) generally requires a significant investment in personnel time, hardware and/or software. Image based methods, such as digital photogrammetry (Chandler, 1999;Lane, 2000;Butler et al, 2002;Chandler et al, 2002;Baily et al, 2003;Carbonneau et al, 2003;Westaway et al, 2003;Gimenez et al, 2009;Marzloff and Poesen, 2009;Lane et al, 2010), have steadily been decreasing in costs. Photogrammetry is becoming accessible to a wider base of users following the development of methods allowing for the accurate calibration of non-metric cameras and the increasingly reliable automation of the photogrammetric process (e.g.…”

Effect of dyke construction on water dynamics in the flooding savannahs of Venezuela

“…This is also one of the biggest problems when working in very flat areas, because often contour lines and height points are not very dense in the available topographic maps (Marks and Bates, 2000). Although a DEM can also be created with digital photogrammetry techniques (Baily et al, 2003;Lane et al, 2000), the required accuracy is frequently not met by the data. This is especially the case when working in countries where very little topographical data and few large-scale aerial photographs are available, as is often the case within humid tropical areas (Hudson and Colditz, 2003).…”