When someone mentions ‘laser scanning’, do you instantly think of scanners mounted on tripods spinning around? Or maybe colorful aerial maps of a city? Terrestrial and aerial 3D mapping are certainly well-established methods for capturing the existing conditions of a building or an industrial plant or a large urban area.
But what about mobile laser scanning? It may not be the type of laser scanning that leaps to mind, but the use of laser scanners for mobile mapping—particularly for infrastructure projects with corridors such as roads or railways—are on the rise. And considering the amount of work needed to upgrade and expand our infrastructure systems, the use of mobile mapping is becoming increasingly common, from large multi-decade mega projects to rather more mundane state and municipal projects.
To refresh your memory, mobile mapping systems use scanners mounted on moving vehicles with equipment to calculate and compensate for the vehicle’s location and movement. These systems can quickly produce topographic surveys of drivable corridors. Existing roads, bridges, utilities, and so on—as well as the surrounding cityscape or landscape—can be digitally captured while traveling at highway speeds without exposing survey crews to traffic or requiring road/lane closures. The resulting point cloud data can then be imported into 3D modeling software to support planning, design, construction, or maintenance efforts.
As laser scanning technology improves and prices drop, mobile mapping is becoming a cost-effective, tool for companies of all sizes—even small firms such as Sorrell-Smith Engineering Consultants (2SEC), an engineering design, planning, and construction management company located in West Memphis, Arkansas. 2SEC has under a dozen employees, but with strong industry know-how combined with mobile mapping tools, the firm is able to provide services many of its competitors cannot. 2SEC’s use of mobile mapping was recently profiled in the July/August issue of LiDAR Magazine.
Click here to read the full article, but below are some of the highlights related to one of their current mobile mapping projects.
2SEC is working on a subcontract with Crisp Construction for a six-mile widening/reconstruction of U.S. Route 64 in eastern Arkansas. 2SEC’s activities include grade calculations and construction layout work. Instead of assigning a dedicated crew to perform a manual survey, 2SEC decided to use its Topcon IP-S3 mobile mapping system for a digital survey of the six-mile stretch.
The project is still ongoing, but so far 2SEC has used mobile mapping to capture all of its original data—the existing centerline and edge of pavement grades—to generate the road’s existing profile. The captured data is post-processed using Topcon’s scanning software as well as ReCap, and ultimately the data is transferred to a modeling solution such as Civil 3D. As the project progresses, 2SEC will use mobile mapping for a final survey to obtain the cross sections needed for earthwork calculations.
2SEC reports that on projects such as this one, mobile mapping technology enables just one of their staff to capture the survey data that generally would a week for two full crews to capture. The benefits of mobile mapping are clear, even for a small firm like 2SEC: increased productivity, reduced crew size, and enhanced safety.