Humans have a long history of observing and measuring the earth to find distances, define borders, and create the built environment. People have used tools to accomplish this since the earliest hand-inked maps and now-forgotten measuring units (for example, cubits). Today, with emerging and advanced technological resources available, engineers can address the same needs with unprecedented speed, detail, and flexibility.

The field that gathers and manipulates planetary measurements and imagery is called geospatial analysis. The field employs an assortment of specialized tools, and highway design and construction professionals make extensive use of data from geospatial tools. Recently, technological advances have emerged that are providing increasingly robust geospatial information, with an outcome of powerful new efficiencies in highway design and construction practices. Highlighted in this article are four technologies that represent these advances.

Unmanned Aerial Systems

Unmanned aerial systems (UAS), also called drones, have quickly become versatile platforms for collecting geospatial data. Available in many sizes and forms—with the quadcopter (four rotor blades) being the most common—they are popular for surveying and mapping because of their relatively low cost, ease of use, and fast deployment capabilities.

Increasingly, UAS are employed for other engineering and construction tasks, such as material quantity estimation and field inspection. As the use of UAS increases, it is important that users of this technology understand and follow the rules governing its use.

LiDAR

A technology gaining traction for geospatial use is light detection and ranging, more commonly known as LiDAR. These laser-based devices can rapidly acquire three-dimensional (3D) geometric data (termed "point clouds") efficiently and with unprecedented detail.

With advancements in sensor miniaturization and reduced power needs, LiDAR units are now adaptable to many platforms, including aerial (UAS), terrestrial (tripod), and mobile (vehicle). Accuracy levels vary by platform type, and users should be aware of these differences and their potential impacts on a project.

Structure from Motion

Using principles that are not fundamentally different from those of conventional photogrammetry (the art and science of taking measurements from photographs), Structure from Motion (SfM) is a technique that uses advanced digital image-matching algorithms. The algorithms were originally developed for the machine-vision market.

Because of its relative ease of use and ability to generate very high-resolution point clouds and 3D images, SfM is a technology that is positioned to be a game-changer for mapping and model development.

Global Navigation Satellite Systems

Global navigation satellite systems (GNSS) are configurations of orbiting satellites that provide geospatial positioning data to receivers on earth. This technology is widely exploited by common consumer devices such as smartphones and in-car navigation systems. GNSS are also the core positioning technology for advanced highway surveying and automated construction equipment, including real-time kinematic units and automated machine guidance systems.

Currently, two GNSS are fully operable: United States' Global Positioning System (GPS) and the Russian Federation's Global Orbiting Navigation Satellite System (GLONASS). GPS is currently the predominant data source for the Western Hemisphere; however, many newer devices support GLONASS as well. GNSS from other nations are under development, with ongoing international efforts to ensure these systems are interoperable and fully available for civilian applications.

Selecting the Right Tools

With broad and sometimes overlapping capabilities, selecting the appropriate technology for a program is important. One key to success is choosing the tools with capabilities best matched to well-defined program goals. In practice, highway design and construction professionals often use multiple systems together to capitalize on the strengths of each. In addition, these technologies can be coupled with existing systems, such as automated machine guidance and advanced surveying instruments.

Because product size has been reduced and costs are lower, advanced geospatial tools are increasingly available for a wide range of highway design and construction applications. The tools highlighted here are quickly bringing change to a discipline historically characterized by gradual advancement.

Morgan L. Kessler, P.E., is a highway research engineer at FHWA's Turner-Fairbank Highway Research Center.