From its ancient past to present-day modern construction, the profession of site surveying has evolved into a fine art, driving plan metrics from 2D to 3D to single-centimeter accuracy over the course of time. The practice dates back to 1,400 B.C. Egypt, where land surveyors used a variety of ropes, plumb bobs and other devices to mark property lines for governments and landowners. The Chinese advanced the process, introducing the first magnetic compass for directional alignment around 200 B.C. Later, in the late 1500s, theodolites for boundary lines came into being, with sextants for measuring angles following in the mid-1700s. Today, global positioning systems (GPS), geographical information systems (GIS), global navigation satellite systems (GNSS), ground-penetrating radar (GPR), building information modeling (BIM) and advanced robotics are removing the guesswork from the surveying profession and pointing the way toward absolute accuracy.
This article will highlight a few of the groundbreaking developments in the art of site surveying and provide some examples of how forward-thinking contractors are using innovation to improve accuracy, speed, safety, productivity and total project return on investment (ROI).
A Complex Dance
The goal of a site survey can vary depending on the stage of a construction project. Surveys determine boundaries, topology, construction plans, subdivision parcels and land titles, all requiring particular maps and measurements to advance the project.
These surveys assist planners, architects, engineers, local governments and contractors in completing their jobs accurately. In construction, a site survey will account for factors such as soil type, utility locations, vegetation and adjacent land usage affecting the potential construction site.
Background details such as zoning maps, local permitting laws, drainage patterns and other environmental factors must all be examined and documented as part of the process.
Boundaries and control points, staked out in relation to existing infrastructure, present a complete picture of where and how actual construction must progress to satisfy the planner’s objectives.
A quality survey sets the tone for the entire project. Each pylon, column and foundational element must be precisely located and marked to guide the work. In the course of a project, thousands of such points may come into play.
“Many of these technologies are combining to provide the full data necessary to prevent material shortages or labor overruns on an active jobsite,” said Troy Dahlin, Leica Geosystems vice president of heavy construction for the U.S. and Canada. “By connecting the dots, the correct information can be read in real-time, allowing a request to be submitted in time to keep a running project on track.”
Where two humans may have to measure horizontal and vertical angles manually by aiming a reader at distant targets, automated total stations can collect the same data and set stakes using one robot controlled by a single human.
“Augmented reality (AR) is another emerging technology that can reduce errors and rework,” said Ray Kerwin, Topcon Positioning Systems director of global product planning. “AR allows you to overlay digital information onto a physical site for better visualization. You’ve seen it on football broadcasts, where the first down markers are projected onto the field. It’s a visualization aid that allows you see what the data looks like on the ground.”
Another quick and easy way to gather accurate, site-condition information is through point cloud scanning. Point cloud scanning produces geo-referenced, 3D models of an area. It’s built on millions of spatial data points captured through a 3D laser tool.
“Let’s say you forgot to measure the location of a manhole on a property. You could use a point cloud to pinpoint that manhole on the map and measure its exact location using realistic site data,” said DiBenedetto, whose company helps civil construction firms deploy site surveying technology. “If it’s visible on the point cloud, you can measure it.”
Other rising stars on the surveying technology horizon include:
- GNSS corrections networks: Integrated directly with survey devices to enable cm-level accuracy.
- Construction layout robots: Rovers, featuring GNSS corrections, perform layout tasks directly, reducing tedium associated with layout.
- Ground-penetrating radar: Uses radar to survey the subsurface (underground utilities, metals, pipes, cables, etc.), revealing potential production challenges.
Robotic Total Stations
One of the most reliable and prevalent surveying technologies available on the market is the robotic total station (RTS). This technology emerged in the 1970s, incorporating electronic distance measuring (EDM) with a theodolite to measure horizontal and vertical angles.
Data collected was stored separately. By the 1980s, remote-controlled robots were introduced, adding significant flexibility and safety to the equation, as surveys could be performed in hard-to-reach places, from a distance, without a separate data cache. “Robotic total stations automate layout tasks, reduce reliance on manual measurements, and increase precision,” said Kerwin, who represents the Topcon LN-150 single-operator, 3D laser RTS solution. “This technology is extremely easy to use, and the one-operator design boosts productivity while saving labor costs.”
RTS robots follow a handheld prism around a jobsite, with the “smart end” of the pair located at the prism. As it follows the prism from point to point, the robot accurately captures the measurements, delivering extreme accuracy with speed.
Leica Geosystems solves the problem of “seeing” around field obstacles with its AP20 AutoPole, an intelligent prism rod that allows users to measure inaccessible points by tilting or adjusting the rod’s height. “The pole ensures high accuracy regardless of what the person holding it does,” said Dahlin. “As a result, human error can be eliminated, and the user can capture more layout points in less time.”
As RTS and total station technology continue to evolve, look for advancements in artificial intelligence (AI), data collection and analysis software and mobile devices to make site surveying even more accurate and efficient.
How to Get Started
The benefits of advanced technology in site surveying and layout are numerous. Less labor and fatigue, better coordination and consistency, improved productivity and safety, reduced rework, turnaround time and cost all make the case. However, many in the industry are just now making the move to digitize their site surveying process.
Trimble’s DiBenedetto said, “You can get a lot of quality information on the topic without a sales pitch by just watching videos on the topic online. Then, once you decide to get serious, you’ll have a basic understanding of the technology and know what questions to ask.”
Trimble’s ”SITECH Solutions” YouTube channel provides a broad selection of educational videos on the latest technologies, as do other vendor channels dedicated to advancing the profession. From there, you can get a good idea of who to call and start a dialog.
Look for a bona fide solutions partner in the process, not just a sales outlet that is liable to upsell you or leave you on your own after the purchase is made. Request a demonstration and see what’s available before you create a short list.
It’s always wise to start small and gradually grow your arsenal to include more advanced tools as you go. “You’ll want to find a device or technology stack that is easy to work with at the start,” said Gladbach, who recommends finding a provider who will listen to your needs and help you decide on a solution that best fits your specific requirements.
“I would suggest buying or renting an inexpensive [real-time kinematic (RTK)]-enabled survey product, such as a drone, and configuring it yourself as a test run,” he said. “They’re fairly easy to operate and you’ll quickly get a feel for the technology without having to be technology expert.”
Point One Navigation offers a free trial of its Polaris RTK device for anyone interested in giving it a try.
Dahlin of Leica Geosystems said, “Don’t try to swallow the whale all at once. Find technology that speaks your language, look for an intuitive user interface, and keep it dirt simple. Your employees must be able to use it to adopt it, and that’s the best way to break it in.”
Other things to consider as you make the move to automate include compatibility with existing software and workflows, easy connections to mapped corrections networks, availability and access to training and training documentation, and keeping the toolbox all within the same brand for quick, consistent expansion.
It’s also well to note that much of the surveying technology that’s out there may often be compatible with onboard machine control systems, allowing you to leverage your survey tech purchases with earthmoving equipment.
“If the same GISS hardware you purchased to improve your survey results can be placed on an excavator to guide the machine to exact locations on a site, you’ve basically enhanced the value of your purchase by that much,” said DiBenedetto.
Enhance Accuracy, Efficiency and Safety With Automated Surveying Technology
Site surveying technology makes every job easier. It improves the accuracy, range, speed and efficiency of the work, and frees your team to focus on building quality projects that turn a profit. If you aren’t already using the technology, appoint an internal surveying tech champion to lead the charge, select a pilot project and begin. You’ll soon find that better outcomes, cost savings and improved project management are well within reach.
