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Three-dimensional (3D) visualization is rapidly becoming an important tool for many engineering projects. Accurate digital representations of terrain and ground features are extremely useful for efficient design, communication and data representation in projects involving land development, transportation planning, hydrologic analysis, environmental impact studies, and much more. Within the scope of terrain modeling lie a wide variety of techniques used to build digital elevation models (DEMs). Each approach has inherent problems and difficulties that can alter the accuracy and usability of the DEM produced. The main objectives of this study are to examine the various methods used for the creation of digital elevation models and make recommendations as to the appropriate techniques to use depending on specific project circumstances. Data sets generated using two of the methods, photogrammetry and LIDAR, are used to build digital terrain models in various software packages for an analysis of data usability and function. The key results of this research project are two DEMs of a real-world transportation study area and a set of conclusions and recommendations that give insight into the exact methods to be used on various projects. The paper ends with two short appendices, the first of which discusses several software packages and their effectiveness in DEM creation and 3-D modeling. The final appendix is a flow chart summarizing the recommendations for the seven DEM creation methods. / Master of Science

No description available.

No description available.

The Givens orthogonalization algorithm is an efficient alternative to the normal equations method for solving many adjustment problems in photogrammetry. The Givens method is one of a class of methods for solving linear systems known generally as orthogonalization or QR methods. It allows for sequential processing and greatly simplifies the computation of statistics on the observations and residuals. The underlying reason for these advantages is the immediate availability of the orthogonal Q matrix, which is computed as the data are processed and is intimately related to the statistics needed for blunder detection. One of these statistics, the F statistic computed from externally studentized residuals, is both easily obtained and well-suited for blunder detection. The Givens method requires nearly four times the number of computations as compared to the normal equations approach in order to reach a solution. However, depending on the size of the problem, blunder detection through the normal equations requires far more computer time than is required when starting with a Givens decomposition. The method allows a user to review intermediate results, test residuals and modify the solution without having to compute a full solution. Adjustments of a level net and a single-photo resection are used to demonstrate the method. Because of the advantage in computational time, the Givens method is superior to the normal equations approach when rigorous blunder detection is required. / Master of Science

Sandy beaches are vulnerable to extreme erosion during large storms, as well as gradual erosion processes over months and years. Without monitoring and adaptation strategies, erosion can put people, homes, and other infrastructure at risk. To effectively manage beach resources and respond to erosion hazards, coastal managers must have a reliable means of surveying the beach to monitor erosion and accretion. These elevation surveys typically incorporate traditional ground-based surveying methods or lidar surveys flown from large, fixed-wing aircraft. While both strategies are effective, advancements in photogrammetric technology offers a new solution for topographic surveying: Structure from Motion (SfM). Using a set of overlapping aerial photographs, the SfM workflow can generate accurate topographic surveys, and promises to provide a fast, inexpensive, and reliable method for routine beach surveying. Unmanned aerial vehicles (UAVs) are often successfully employed for SfM surveys but can be limited by poor weather ad government regulations, which can make flying difficult or impossible. To circumvent these limitations, a digital camera can be attached to a tall pole on a mobile platform to obtain aerial imagery, avoiding the restrictions of UAV flight. This thesis compares these two techniques of image acquisition for routine beach monitoring. Three surveys were conducted at monthly intervals on a beach on the central South Carolina coast, using both UAV and pole photogrammetry. While both methods use the same software and photogrammetric workflow, the UAV produced better results with far fewer processing artifacts compared to pole photogrammetry. / Master of Science / Beach environments are vulnerable to extreme erosion, especially in the face of sea level rise and large storms like hurricanes. Monitoring erosion is a crucial part of a coastal management strategy, to mitigate risk to coastal hazards like extreme erosion, storm surge, and flooding. Erosion monitoring usually involves repeated elevation surveys to determine how much sand is being lost from the beach, and where that sand is being eroded away. Within the past decade, Structure from Motion (SfM) photogrammetry, the process of deriving ground elevation maps from multiple overlapping aerial photographs, has become a common technique for repeated elevation surveys. Unmanned aerial vehicles (UAVs) are often used to gather aerial imagery for SfM elevation surveys but are limited by poor weather conditions and government flight regulations, both of which can prohibit flight. However, similar aerial photographs can be taken with a camera mounted atop a tall pole, which can be used in wider range of weather conditions and without government regulations, providing an alternative when UAV flight is not an option. This study compares these two platforms for routine beach erosion monitoring surveys, evaluating them based on performance, cost, and feasibility. The UAV system is found to be fast, affordable, and effective, while the pole photogrammetry system is heavily affected by the slow speed of surveying and processing errors that make it unusable without significant improvement.

No / ‘Project code-named Humpty’ is a performative art piece involving the creation, fragmentation, and reconstruction of a 2.7 m high classically inspired sculpture. It was conceived to complement an archaeological science research project setting out to explore the use of digital scanning technologies in artefact reconstruction. The statue’s form was free sculpted in clay over a period of four years. It was cast in a self-supporting cementitious material specifically for the purpose of ceremonial fragmentation and subsequent reconstruction by archaeologists. In this chapter, we explore the project’s human/machine intentions, interactions, development processes and their wider implications leading to fragmentation. We explore how 3D terrestrial laser scanning with photogrammetry was used to chart the creation of the sculptural form and how scans informed finite element analysis, essential for safe casting and fragmentation. We show how structured light scanning was essential to create a digital backup of the mould and how drone imagery documented fragmentation tests and 360° imaging recorded studio and quarry activity. / We are very grateful to AHRC, the Arts and Humani[es Research Council who in 2017 awarded follow-on funding to support ‘Project code-named Humpty’ (AH/R004846/1), linked to the AHRC Digital Transformations Theme Large Grant ‘Fragmented Heritage’ (AH/L00688X/1). Highlight Digital Transformations, linked to the ‘Fragmented Heritage’ Project, funded under the Arts and Humanities Research Council’s Digital Transformations Theme Large Grant.

Thesis (M.S.)--University of Michigan, 1970.

Thesis (M.S.)--University of Michigan, 1969.