Terrestrial Laser Scanning: Reducing the risk of Accurate Spatial Information

In a world where the elimination of risk is a ceaseless endeavor, spatial information is a critical component of any project. In order to reduce project risk, professionals need to ensure they use the right technology and expertise, for the right application, for the right geographic location. Today, professionals in engineering, surveying, construction, transportation, oil, mining, pipelines, and utilities simply can't know all aspects of spatial technology and their applications. Technologies such as satellite imagery, terrestrial laser scanning, airborne LIDAR and rapid prototyping are becoming key components of projects requiring accurate, detailed spatial information.

In the coming weeks and months, the Spatial Resources Letter will investigate spatial technologies to provide objective, independent, information tailored specifically to your spatial information needs, because in the spatial information industry there are no "one size fits all" solutions.

What is Terrestrial Laser Scanning?

This issue focuses on terrestrial laser scanning, a technology that creates accurate three-dimensional images of real-world objects and existing conditions. A laser scanner records millions of highly accurate, unique points by sweeping its beam over a surrounding scene or object. The scanners X,Y,Z measurements are recorded and displayed as a "point cloud" which can be viewed, measured and navigated as a 3D model providing incredible insight to the scene.

Terrestrial laser scanning has been in practical application since the mid-to-late 1990s. It is ideal for applications where highly accurate, 3D spatial information is required, such as: Construction site and engineering surveys, corridor or pipeline mapping, transportation surveys, and facility and plant as-built designs, just to name a few. If accurate spatial data is critical to your project, then laser scanning reduces your risk by an order of magnitude.

Laser Scanning Applications

Civil engineering and surveying companies are using laser scanning to provide accurate, complete topo data for design of highway transportation projects. Surveying roads and highways, particularly with active traffic or damaged bridges is best accomplished with laser scanning. Capturing complete 3 D data allows them to develop TIN meshes of the roadway surfaces, portal openings and overhead beams determining where absolute minimum clearances exist. For transportation surveys, laser scanning demonstrated about 75% savings in labor costs compared with traditional surveys, plus provided more detail and was much safer to deploy.

For construction site & engineering surveys, laser scanning demonstrated more than 60% labor savings, provided greater detail, and benefit from 3D visualization. Volume calculations, measuring quantities of rock, stockpiles of materials, quarry faces, mining or landfill applications can be surveyed economically with resulting detail that would be difficult to meet through traditional, ground-survey methods.

Laser scanning is used in major retrofit projects of complex industrial and power plants. Accurate as-built plans and models of plants and facilities allows for better design and construction planning, provides major savings by reducing field change orders and in capturing and creating as-built designs. In addition, demolition and construction sequences can benefit from point cloud data to detect interferences and perform conceptual and final design.

Laser scanning technology can be used to capture complete, highly detailed, accurate 3D geometry. Profiles, volumes, area calculations can speed architectural plans & elevations providing computer models as input for automated interference checking and detailed design. As well, building facades can be captured quickly in three dimensions for cultural and historical surveys.

Interesting developments that are beginning to emerge are the integration of laser scanning with other geographic data moving toward the creation of truly accurate and detailed 3D geographic information systems. Also, consider laser scanning architectural, cultural and historical objects to create 3D digital models which can then be output as physical scale models using rapid-prototyping technologies. Imagine capturing Machu Pichu or any number of countless historic and archaeological sites around the world, creating a permanent, accurate, digital 3D record of it, then out-putting to a physical scale model for educational, entertainment or business use.

Benefits of Laser Scanning

The high-density accurate data, speed of data capture, the safety and convenience of remote acquisition and measurement, 3D visualization and digital imagery are the distinguishing features of laser scanning that provide the greatest benefits. Abundance of data captured in laser scanning reduces questionable data, provides over sampling to ensure accuracy and that all objects, structures, geometry are captured. High point density data ensures a complete topographic survey: All details are captured and all data captured are direct measurements. Imagery and 3D visualization provides added confidence that mapped objects correspond to actual existing conditions.

Now, it is important to keep in mind that not all laser scanners are created equal, nor are laser scanning service providers. The results derived from various laser scanning equipment and laser scanning service providers can vary from scanner to scanner, service provider to service provider and laser scanning application to application. Therefore, the success of a laser scanning survey depends upon using the right scanner and the right scanning service provider for the right project.

This article is the first in a series to provide you with insight to the various spatial technologies such as satellite imagery, terrestrial laser scanning, airborne LIDAR and rapid prototyping, their uses and applications. As mentioned earlier, our goal is to provide you with objective, independent, information tailored specifically to your spatial information needs because in the spatial information industry there are no "one size fits all" solutions.

So, if you would like to learn more about any of these technologies, including laser scanning, how they can benefit your spatial information needs, or just for general information, please feel free to contact us. Visit our web site at www.spatialresources.com, email us at info@spatialresources.com or call one of our advisors at 720-934-2482.

Until next time...Cheers!

Roland Mangold