2015 Issue

34 H IGH DEFINITION SCANNING (HDS) technology is an efficient and powerful alternative to surveying for virtually all surface definition, topographic or structural situations. Manually surveying sites for ground/object surface or struc- ture details can requiremany, many hours, sometimes over several days, and sometimes involving potentially hazardous locations, such as petroleum refineries or electrical installations. HDS tech- nology makes it possible for data to be remotely collected from literally millions of surface points, with densities and accuracies less than 0.1-inch in a matter of hours instead of days or weeks. HDS technology is based on an imaging LiDAR (Light Detection and Ranging) laser and a receiver that collects up to 1-million survey shots per second, making it easy to provide data that can be used for volume calculations, 2D line work or 3D models. This data can be easily converted into formats such as AutoCAD, which is a standard engineering design tool, as demonstrated below. Efficiencies That Lead To Savings A national consulting firm recently undertook the renovation of a hydroelectric power plant here in Utah. “We needed to evaluate some existing structures, including a powerhouse that is about 100 years old,” the Project Manager explained. “I knew about HDS type of scanning, and thought it would be a good applica- tion for the project. So, we engaged an experienced HDS team to do that for us. Their scanning captured all of the information about the building in a very quick and efficient manner, enabling us to plan around the existing structure with very accurate detail.” Shown left is a se- quence of (Figure 1) a Photo of a Scan Location (a mineral processing facility), and (Figure 2) the resultant 3D LiDAR Scan Model Image. Note the precise facility detail in the LiDAR Scan Model Image. Many processing facilities, e.g. petroleum refineries, require virtually continuous expansion or modification in order to deal with changing product requirements. Such facilities have a real need for accurate 3D definitions of their processing units. LiDAR Scanning is a natural choice for this application. The resultant data package can be ma- nipulated to yield precise 3D descriptions of every element in the facility. Hence, modifications or additions of, say piping arrays, can be made with confidence of adequate clearances and/or precise connections. Figure 3 is a complete lower resolution facility scan image of a refinery facility. This image was produced from a total of about four scanning hours by the field crew. Impressive! High Definition Scanning vs. Conventional Surveying By David W. Eckhoff, PhD, PE and McNeil Engineering, HDS Team Figure 1 - Scan Location Figure 2 - 3D LiDAR Scan Model Image Figure 3 - Composite Refinery Scan (Lower Resolution)