Geologic photogrammetry using standard small-frame cameras

Multi-model photogrammetry enables precise three-dimensional measurements from strips or blocks of overlapping small-frame photographs (colour slides). The method can be used for geo-scientific terrain analysis and mapping. Of special interest is the ability to map otherwise inaccessible terrain features such as geological outcrops on steep mountain faces and canyon walls. Field photography is carried out without special photogrammetric training using ordinary small-frame cameras. Photographs can be taken at any scale and angle from terrestrial stations, helicopters, light planes, or boats. In the laboratory, strips or blocks of small-frame photographs are set up in an analytical stereo-plotter where multiple stereoscopic model pairs are simultaneously orientated. Interpretation and compilation is continuous across model boundaries. Data can be plotted in many different projections. The multi-model photogrammetric technique is explained and procedures are outlined for camera calibration, photography, and acquisition of ground-control information.