Trimble technology delivers on accuracy with high-precision laser scanner
In January 2021, a team of geospatial mapping specialists in the UK visited the 900-year-old Newcastle Cathedral Church of St Nicholas. The company, Gridmark Survey, was there to use a new state-of-the-art 3D laser scanning technology in the restoration of the cathedral. They would assist Historic Property Restoration, and Classic Masonry with site engineering. Gridmark would provide dimensional marking of the groundworks and paving to the new outdoor terrace in the Cathedral churchyard.
The firm was using the new Trimble X7 laser scanning system, a high-precision, rapid-fast modern laser scanner, which captures millimeter-accurate reality data. Gridmark collaborated with KOREC Group, the UK Trimble distributor who provided the technology.* The Trimble® X7 3D laser scanner is integrated with Trimble Perspective software and specifically designed for in-field control and registration.
“We knew we could revolutionize how the stonework was inspected and measured and show that we could speed up the process by more accurately measuring the masonry without scaffolding and additional labor,” said Christopher Mooney, managing director and senior surveyor with Gridmark Survey. Safety was also important to Gridmark but the X7’s remote sensing capability eliminated the need for safety training, saving valuable worker time.
The scanning team consisted of two surveyors on site for three days. During that time, they captured details of the building’s 14th-century interior. “We collected 104 laser scans and 3.7 billion measurable points,” Mooney said. “There were three or four rooms not accessible, or it would have been 110 scans and 4 billion points.”
In some places, pollution had eaten away much of the stonework. With the X7 they could zoom in on an area and provide details of the damage immediately. “One window was extremely deteriorated on the outside but beautiful inside so you could see how it was supposed to look,” Mooney said. “That level of detail captured by the scanner was phenomenal.
“It would take a stonemason six weeks to inspect and measure what we scanned in three days with the Trimble X7 scanner,” Mooney added.
Gridmark also had access to the Cathedral’s Lantern Tower, a climb of 162 steps. They set up the scanner and captured 360-degree scans from the tower, the roof and the adjacent buildings. Each time they moved to a new position, the X7 automatically leveled and calibrated itself and the Perspective software automatically registered each scan, allowing them to review everything in 3D before moving on.
Once the scanning was complete, Gridmark imported the data into Trimble RealWorks® software to create a 3D capacity for making a point cloud as well as a scaled digital model of the Cathedral. Creating a 3D representation of the Cathedral ensured that the detail and design was preserved forever.
Mooney’s appreciation for the X7 grew throughout the project. “It is so cool and quick. The user interface is very intuitive, and we like the high-sensitivity mode that allows us to capture difficult surfaces. We also like the ability to flip between different scans to see more detail.
“We were blown away by the data we downloaded at the end of the day,” he noted. “Trimble RealWorks has the capability to make point clouds look very much like real life. We ended up with data so rich it was hard to know what to choose to share with the client. What was most important, though, was that we had absolute confidence in the results. We knew that 900 years of heritage had been safeguarded.”
*Gridmark purchased the X7 after winning KOREC’s 12 days of Christmas’ celebration and receiving one week free use of the scanner.
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Trimble Geospatial propose des solutions matérielles et logicielles à la pointe de la technologie pour les professionnels du levé terrestre, du SIG, du scanning, du mobile mapping, de la télédétection, de la photogrammétrie et de l'expertise.