Capturing the reality of land surveying

A team at Houston Engineering says that as technology such as LiDAR continues to improve, so will survey methods

Houston Engineering - Reality Capture
Chad Qualley and Erik Nelson, drone operations manager and senior technician, respectively, review work at a computer at the Houston Engineering office in Fargo, N.D.

It’s not virtual reality -- it is reality capture.

Nor is the technology exactly new, but it is the future of land surveying, according to professionals at Houston Engineering, who say it is advancing the ways in which data is gathered and how that information is processed to create designs for, in the company’s role, infrastructure projects.

Think of reality capture as a high-end, cost-effective survey solution that goes beyond traditional survey methods. It uses LiDAR -- which stands for Light Detection and Ranging -- to create high-resolution models of ground elevation.

Chad Qualley and Erik Nelson, drone operations manager and senior technician, respectively, said Houston Engineering, based in Fargo, N.D., has been at the forefront of providing reality capture services that can be used in a variety of applications for clients across the upper Midwest. The survey service improves accuracy, productivity, quality and safety throughout clients’ infrastructure projects.

“LiDAR is actually one of the tools that we use for reality capture and it's one of the biggest ones, really,” Nelson said. “When you can spray an area with billions and billions of points, you basically get a right-now image capture of what's going on at the site you want to capture.”


PointCloud - Houston Engineering
This point cloud image, captured by LiDAR, shows a road project. LiDAR, which stands for Light Detection and Ranging, sends out millions of points of light that capture the details of survey projects.

LiDAR works like this: A laser scanner transmits brief pulses of light to the ground surface. When reflected back, their travel time is used to calculate the distance between the laser scanner and the ground, according to the U.S. Geological Survey . Data is collected as a “point cloud” or dataset “of individual points reflected from everything on the surface, including structures and vegetation.”

LiDAR, of course, is nothing new. It has been around a long time, Qualley said, and he’s been using it ever since he arrived at Houston 18 years ago. “But it has really changed,” he said, mainly because other technology has changed.

“The sensors that shoot the lasers, which is LiDAR, have gotten to be so much more precise and so much more inexpensive,” Qualley said, explaining that LiDAR can now be used on much smaller projects than in the past.

Qualley described himself and Nelson as “software experts” who run “various specialized software” that allows them to process the “point cloud that the LIDAR sensor shoots and extracts from.”

It is similar to having a field survey crew on site, extracting information from all points of a location.

“We're extracting out road edges, we're extracting out signs, we're extracting out a grid of points that then can be used to make surfaces,” Qualley said. “It’s really changed.”


To give another example of what has changed, traditionally high-altitude LiDAR has been captured with a plane, but new aerial LiDAR techniques can use a helicopter or unmanned aerial system that can fly safely at lower altitudes to help produce more detailed results. Nelson said mobile LiDAR can capture images close to the ground with a device mounted on a vehicle.

What’s on the horizon with reality capture is anybody’s guess, because technology changes so quickly. Even over the past couple of years, the team at Houston Engineering has seen it evolve and enhance.

“The sensors have gotten immensely better in the last four or five years, even over the past couple of years,” Nelson said. “It's just been insane how they've changed the style and the ability of each sensor and then each iteration gets that much better than the last one.

“So, going into the future it's only going to get that much better. The sensors are going to get smaller, they're going to get more accurate. It's just going to continue going that way.”

He said drones also will get better and, fingers crossed, eventually be able to carry more weight. Sensors are heavy for a drone.

“That’s one limitation we have,” Nelson said, “but hopefully we can get drones that can carry better sensors. So, that's what I see in the next five years, that reality capture will just keep getting better and better with technology.”

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