TY - JOUR PY - 1987// TI - Monitoring landslide movement with a 35-mm camera JO - Transportation research record A1 - Ballantyne, J. D. A1 - Dean, D. R., Jr A1 - Thompson, B. L. SP - 47 EP - 54 VL - 1119 IS - N2 - The methods of analytical photogrammetry and microcomputer technology are combined to generate contour maps or cross sections, or both, of landslides along roadways with minimal conventional surveying. A conventional 35-mm camera and 8-in. by 10-in. photographs are used for the mapping. A minimum of two overlapping photographs are needed of the area to be mapped. Also, a minimum of six well-distributed control points are needed. Control points are points for which position (X and Y coordinate pair) and elevation (Z) must be obtained by conventional surveying techniques. The photogrammetric model used is the direct linear transformation model. This model uses x and y coordinates of corresponding images on two or more photographs to determine the position and elevation of such images in a ground-based coordinate system. A microcomputer performs the calculations and an electronic digitizer connected to the microcomputer is used to obtain the image coordinates on the photograph. The ouput can be in the form of a coordinate list of desired points, cross sections, a contour map, or three-dimensional perspective plot. The graphics are generated by a pen plotter connected to the microcomputer. Studies indicate that the error vector at about 400 ft is 0.4 ft for this system of mapping. A slope in distress can be monitored over a period of time. To eliminate resurvey, the six control points have to be located in a stable area. Record URL: http://onlinepubs.trb.org/Onlinepubs/trr/1987/1119/1119-006.pdf TRT Terms: Cameras; Graphics; Information processing; Landslides; Linear differential equations; Mapping; Microcomputers; Monitoring; Photogrammetry; Photographs; Transformations (Mathematics) Old TRIS Terms: Graphic methods; Linear transformations Subject Areas: Geotechnology; Highways; I42: Soil Mechanics

Language: en

LA - en SN - 0361-1981 UR - http://dx.doi.org/ ID - ref1 ER -