Small unmanned aircraft systems (UAS) carrying consumer-grade nonmetric cameras are increasingly utilized to generate high-resolution 3D geospatial data. Low cost, ease of operation, widespread availability and low altitude maneuvering capabilities of UAS, as well as the rapid development of technology and methods, make UAS-based photogrammetry applicable to many civil engineering...
To derive ellipsoid heights on passive marks with cm-level accuracy, many current specifications require the collection and adjustment of long-duration, static Global Navigation Satellite System (GNSS) sessions. To increase efficiency, a survey procedure that includes real-time kinematic vectors from a real-time GNSS network (RTN) was evaluated. Thirty different “hybrid” networks...
Lateral spread is a pervasive type of liquefaction-induced ground failure that occurs on gentle slopes or near free-faces, such as river channels. Resulting horizontal displacements can reach up to several meters, and can be considerably damaging to foundations, bridges, roadways, pipelines, etc. In the 1990s, Bartlett and Youd (1992a, 1995)...