SURVEYING FOR AEC by Matteo Luccio, Editor-in-Chief A New Way to Map New Pipes T he danger of hitting a buried water or gas pipe Gas meters, which also need to be mapped, are often when digging for a construction project persists in locations that are hard to map directly with a GNSS despite many efforts to reduce it, such as “call receiver because line-of-sight to the satellites is obstructed before you dig” phone numbers. For example, by trees, roof eves, or adjacent buildings. Therefore, they in Minnesota there were 4,000 such hits in 2019. That must be shot with an offset. For these situations, Nelton is one reason why it is very important to map “as built” used Eos Positioning Systems’ laser mapping solution, underground utilities accurately. This must be done which enables surveyors to use lasers attached to their quickly and efficiently, before trenches are filled and range poles to feed data directly into their GIS. without slowing progress of the project. No More Battleship. Using Eos Positioning System’s Traditionally, crews have mapped the underground Arrow Gold receiver and the MNCoors RTK network, pipes and cables on paper. Nelton said, his team was able In turn, when a construction Construction crews are expected to average an accuracy of 0.25 project needs to know the throughout a project in the to produce a digital record of location of underground city of Owatonna, Minnesota, their work in real time. utilities before digging, it as confirmed by spot checks typically relies on someone with other survey equipment who consults those paper maps, uses an electromagnetic and with the city’s survey team. “Not every shot was easy, utility locating tool, and marks the ground with spray and some took multiple attempts and tricks of the trade paint. The construction crew then must correctly interpret to get them,” Nelton pointed out. those marks on the ground. In 2019, Minnesota-based On projects in the middle of mountains, where real-utility consultancy Ellingson Companies was asked to time kinematic (RTK) networks do not exist, the company develop a new and more efficient process. has used the Atlas Service, averaging accuracies of 12 in. Capturing Data in Real Time. By leveraging solutions “Given the circumstances of these projects,” Nelton said, from Esri and from Canadian hardware and software “we still consider that to be great.” manufacturer Eos Positioning Systems, Ellingson Using the new system, foremen use a survey in ArcGIS Companies GIS Manager Damon Nelton developed Survey123 to input their inspection notes and other a solution that allows his team to capture new pipe information, feeding it all from the field to the office and construction in real time. By streamlining documentation into layers shared between divisions. This way, the data workflows, the new process improved field productivity are available in real time, not at the end of the project. and allowed Ellingson Companies to produce digital For customers who still want a piece of paper to file as-builts that meet the needs of its gas utility clients and in a physical folder in a filing cabinet, Nelton creates a improve the safety of future construction projects. Microsoft Word document template in their format, While construction crews have been putting pipe in populates it using dynamic text with syntax in ArcGIS Pro, the ground for generations, today they are expected to inserts a map, then saves the Word document as a PDF. produce a digital record of their work in real time — for “At the end of the project, we got almost 17,000 digits the sake of safety and efficiency. with no human entry other than pressing the button on Using Esri’s Utility Pipeline Data Model, Nelton created the barcode scanner, which means zero data errors,” a system that enables crews to map their as-built pipe said Nelton. No pieces of paper with critical data on the projects while also tracking components. The system underground utilities languish in a glove compartment or improves data integrity — in other words, reduces human are eaten by a surveyor’s dog, and all the data is available error — by relying on scannable 16-digit alphanumeric in real time. bar codes developed by the American Society for Testing Additionally, the combination of the barcode scanning and Materials that provide seven attributes for each workflow and the high accuracy GNSS receiver enables conduit, including thickness, diameter, lot number and Nelton’s team to locate gas asset pieces that need manufacturer date. To collect and store these data, Nelton to be replaced — for example, due to a recall by the set up an ArcGIS Enterprise geodatabase. manufacturer — “without playing battleship,” he said. FEBRUARY 2023 | WWW.GPSWORLD.COM GPS WORLD 21
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