Techniques in land surface evaluation
Photogrammetry has traditionally provided a means of generating three-dimensional spatial data to represent terrain surfaces, which complements traditional ground-based surveying methods. Although techniques such as airborne laser scanning (Lohr 1998) and synthetic aperture radar (Hogg et al. 1993; Vencatasawamy et al. 1998) have developed, photogrammetry remains the primary method of generating topographic maps (Wolf 1983; Capes 1998). One important advantage of photogrammetry is the flexibility of scale that allows application to imagery acquired from ground, air and space. Indeed, a new generation of high (i.e. 1 m) resolution satellite sensors (Capes 1998) is likely to further increase the potential applications of photogrammetry. Despite many advantages, there have been several problems with the application of photogrammetry using traditional methods. Most significantly, there was the requirement to use an expensive and complex photogrammetric stereo-plotter. This ensured that the measurement process was slow and generally required the skills of an experienced operator, particularly if results of the highest accuracy were to be obtained.
Rapid developments in computing hardware and software have allowed the science of photogrammetry to develop rapidly during the last ten years (Gruen 1994; Atkinson 1996; Greve 1996). These developments have radically eased many of the problems and limitations associated with traditional analogue instrumentation. Use of a purely numerical or analytical solution provides flexibility, which assists in two important ways. Satellite imagery, oblique aerial photography and ground-based imagery can be used, in addition
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Land Surface Evaluation for Engineering Practice
This volume presents a collection of papers on techniques and case studies in land surface evaluation for engineering practice written by specialist practitioners in the field. The volume arose out of deliberations by the Second Working Party on Land Surface Evaluation set up by the Engineering Group of the Geological Society in January 1997 and chaired by Dr. J. S. Griffiths. The book examples of cost-effective methods for collecting land surface and near surface data prior to carrying further detailed ground investigations of engineering geologist, geotechnical engineers, geomorphologist and planners who have the responsibility for planning a designing investigations of potential sites of development.