PT - JOURNAL ARTICLE AU - R. Welch AU - T. R. Jordan AU - A. W. Thomas TI - A photogrammetric technique for measuring soil erosion DP - 1984 May 01 TA - Journal of Soil and Water Conservation PG - 191--194 VI - 39 IP - 3 4099 - http://www.jswconline.org/content/39/3/191.short 4100 - http://www.jswconline.org/content/39/3/191.full AB - Prediction of gully and channel erosion requires improved measurement procedures. Close-range photogrammetric techniques using relatively low-cost 35 mm or 70 mm cameras, readily available cartographic digitizers, and analytical computational methods can provide conservationists with X, Y, Z terrain coordinates accurate to within a few centimeters. Fieldwork is limited to the recording of stereophotographs at desired time intervals before and after storm events. Laboratory tasks involving coordinate measurement and data reduction require about 2 hours per stereopair. Terrain coordinates are used to form digital terrain models from which contour maps, profiles, and three-dimensional perspectives can be created with the aid of computer graphics routines. By registering digital terrain models from two dates, soil loss due to erosion can be computed. This method offers promise for providing the data needed to develop predictive erosion models and for undertaking site assessments for farm pond or terrace construction.