PITTSBURGH – In the world of carpentry and construction, a famous proverb cautions laborers to "measure twice, cut once," but in the field of survey work, measuring twice is not enough.
Modern-day surveyors use highly advanced equipment to take thousands of measurements to transform data into digital images. The output results in a collection of data points with precise calculations down to the millimeter.
"Run scared," said Tom Schad, a survey technician with the U.S. Army Corps of Engineers Pittsburgh District, when he explained how surveyors treat their craft and their equipment. "It doesn't mean to be afraid of your equipment. It means that whatever equipment you're running, you have to constantly check your work. Otherwise, mistakes happen. Complacency sets in."
Surveyors assist in field data collection for creating various types of maps, determining property lines, assessing topographical changes, or helping develop plans for new construction.
"We are at the frontline of most projects. If there is a new project coming out, we go out before any of the work can begin," Schad said.
Even though surveyors benefit from extremely advanced, GPS-based tools that can capture hundreds of measurements per minute, surveyors still need to be methodical, attentive, and consistent.
"When we're working, I get very focused. I'm not talking to Tom or anybody because we don't want to make mistakes," said Alex Ramsburg, a survey technician and Schad's teammate on most survey jobs.
GPS technology became popular in surveying in the 1980s and 1990s. The tools rely on satellites that orbit the Earth, constantly sending out signals. These signals provide precise timestamps, allowing the equipment to calculate the distance from each satellite.
By triangulating these distances, the equipment determines its exact location on the ground.
"If your device is communicating to 12 or even 20 satellites, you're going to keep taking measurements every minute, every second, so you can get up to hundreds of measurements at one point very quickly," Schad said.
Modern GPS technology has made surveyors' capabilities much more powerful and precise, but Schad said it is critical to rely on traditional methods as well. The team maintains tedious notes, checking their work regularly throughout the course of a project.
"Two weeks ago, we were running an elevation loop, and the instrument I was using just didn't want to cooperate. We had to rely on my field notebook to successfully complete the project. Had I not taken notes, all that information we had collected in the instrument would have been lost. We would have had to do the work again," Schad said.
Some projects require returning to the same location over time to take new measurements to account for changes in the environment, topography, or water levels. Survey teams drive thick nails into the ground to measure areas from the exact same spot every time.
Some sites also have historical markers called monuments. The monuments look like large coins stuck to the ground with a crosshair etched in the center to give surveyors an exact dot where to place their equipment.
The Pittsburgh District has monument markers at all its facilities such as reservoirs, dams, and locks. The markers have been in place since those structures were built, some of which are more than a hundred years old. Over the decades, surveyors return to those spots to field information for new construction or maintenance projects.
"On some of these monuments, we will take hundreds of thousands of measurements over time,” Schad said. “We rely on redundancy, taking multiple measurements on that same point decade after decade.”
The Pittsburgh District survey team is part of the geospatial section which also includes cartographers, aerial drone operators, and hydrology graphic experts who build digital models of different floodplains. The district has four surveyors, two of whom are licensed, and the other two are technicians. Their survey work supports other departments within the district, such as the real estate office, civil engineers, designers, planners, construction, maintenance, dam safety teams, and more.
"I think it is important to take pride in our work because so many others rely on making sure we do it correctly," Ramsburg said.
Some survey jobs can be performed in one day, requiring only 50 to 100 points, while others can be extremely detailed and meticulous. Recently, the team provided a topographic survey of the Emsworth Locks and Dam, which is the first navigation facility on the Ohio River closest to Pittsburgh. The job demanded thousands upon thousands of "shots" to include a huge file collected through Light Detection and Ranging, or LIDAR.
"We did a complete topographic survey, and when I say complete, I mean every nut, every bolt, every grate. You name it. If it was there, we collected it, and it took months and months and months to put it together," Schad said.
During part of the survey, the Pittsburgh District emptied one of the lock chambers completely of water, leaving behind a concrete, rectangular dry area in the river. Surveyors were able to detect whether the pressure from the river caused any movement to the chamber walls to assess their stability. Their tools collected measurements that the naked eye would not be able to see. If they detected even six millimeters of movement on the wall, it would be a cause for concern.
"If you're careless, you could deliver six millimeters of errors with bad technique,” Schad said. “So basically, you could be saying that a lock wall is moving or something crazy is going on, when it's not actually moving at all. Accuracy is one of the most important aspects of the job.”
Schad and his teammate, Ramsburg, love the opportunities that come with the job. On a recent trip to Johnstown, Pennsylvania, they loaded their truck in the morning’s dark hours and watched the sunrise through their window on their drive to a local flood protection project.
"We get to be outside and watch a beautiful sunrise this morning. We're out of the office, enjoying the fresh air of Johnstown," Schad said. "I have been with the district a year and a half, and still, I'm excited for it every time we go out."
Before becoming a surveyor, Schad spent 13 years in mining. When a survey position opened in his former mining company, he jumped on it. He then applied for the Pittsburgh District, which has allowed him to enjoy more of his family life at home.
"Another really nice feature of working with the Army Corps is having the opportunity to spend time and be there for your kids, with flexible work hours. This job has definitely increased my quality of life at home, for sure," Schad said.
Both Schad and Ramsburg said this career is ideal for any college student who loves math and working in the engineering realm but does not want to be locked down to a desk their entire career. The job offers a good mix of technical work and spending time outdoors, while being involved in critical plans for projects that will last decades.
"Just knowing that the work we do will inform the next generation of surveyors, future projects, it really has a lasting effect," Schad said.