As part of a general investigation into road building problems in the rugged terrain of Colombia, a study was made to determine how terrestrial photogrammetric survey methods could be employed to measure the slope characteristics and surface features of landslides. Because of its robustness, portability and ease of operation in difficult ground, a wild p32 metric camera was used with a theodolite to survey 80 different sites, mostly landslides. The report describes basic photogrammetric principles, the equipment used, photographic methods, operating procedures in the field, and analogue and analytical methods of plotting survey data to produce contoured maps and plans. A practical example is provided and an analysis is made of the comparative costs of terrestrial photogrammetric and conventional surveying methods. The report concludes that photogrammetric techniques offer considerable advantages over conventional methods particularly where field time and labour are limited and where sites are either hazardously steep or inaccessible. The techniques clearly have wider application in other areas of highway engineering where, in the planning stages, design solutions and the selection of alignments may depend on the early availability of accurate ground plans at suitable scales. (Author/publisher)
Samenvatting