- Working with Point Cloud Data
- 3D Bim Can Be Created
- Multistation for Rough-Terrain Surveys
- Construction Projects Aided
For decades, the total station used with a prism pole was the de facto, accepted and reliable surveying tool. In recent years, it has been joined by robotic total stations, GPS receivers, laser scanners, handheld tablets and surveying software. These are all great tools, powerful in their own way. But few firms can afford to buy all of them so that they have the right tool for the job no matter what kind of project comes up. Along with their quest for the right mix of tools, surveyors also want to find ways to deploy smaller crews to the field to reduce manpower, save time and maximize productivity. What’s more, acquisition of point cloud technology, where a survey site can be scanned and a massive amount of data points fed into a CAD program to produce a finished plat, continues gaining momentum ever since it was introduced in about 1998.
One of the latest solutions attracting surveyors incorporates several surveying technologies into a single, multi-tasking system, then imports survey data collected into a drafting program to produce the finished diagram. One of the best examples of this capability today is the Leica Nova MS50 MultiStation. The MS50 integrates 3D point cloud measurements into a regular survey workflow. Topographic survey data can be collected and visualized along with precise, detailed 3D scans. The multistation includes extensive, accurate total station mapping, digital imagery and GNSS connectivity.
Survey drawing software complementing the MS50 is the MicroSurvey CAD Ultimate desktop survey and design program, built expressly for surveyors, contractors and engineers. Of particular importance are the software’s point cloud data visualization tools that allow users to easily work with their point cloud or LiDAR data. Using these tools, professionals can cut, slice and view their point cloud in ways previously unimaginable. The software uses a powerful graphics and point cloud engine that allows viewing and working with large data sets of hundreds of millions of points.
Like many survey firms, Van Harten Surveying, Inc. decided renting equipment to handle several LiDAR scanning projects was the best way to learn the equipment’s advantages and disadvantages. After renting various laser scanners and total stations, the Canadian firm ultimately settled on the Leica MS50 and MicroSurvey CAD Ultimate software. Surveyor Ron Mak and his colleagues already were familiar with the MicroSurvey CAD package (Van Harten has 20 licenses deployed), but so far Mak is the only one in his firm using the Ultimate version.
As the company began relying on scanning technology more frequently for survey projects, Mak knew he would need to buy a scanner instead of renting one. Pushing his decision was the fact that, by renting scanners, he had to rely on the vendor to process the point cloud data so that he and other surveyors at Van Harten could deliver a finished product to the client. This not only absorbed valuable project time, but it also meant Van Harten lost some control. So, a few months after purchasing the MicroSurvey CAD Ultimate program, Mak decided it made the most sense to acquire the Leica Nova MS50 MultiStation.
The decision to buy both of these solutions is one Mak has never regretted, mainly because of the ability to integrate point cloud data captured via the MS50 with the MicroSurvey CAD Ultimate software. “Now, when I have an existing CAD drawing of surveys, I can bring linework and data points into the CAD software’s point cloud. This allows me to see where the cloud is relative to my linework. So, if I’m tracing a cross-section in the point cloud, I can have this entered into the CAD drawing as I’m tracing it,” Mak explains.
“I have monitors set up, with point cloud on one monitor and the CAD drawing on the other monitor. As I’m drawing the cross-section in the point cloud, I can see the line appearing on the other screen, in the CAD drawing.”
Accomplishing rooftop surveys is a good example of the typical types of projects Van Harten tackles. “It’s an important kind of surveying,” says Mak, “because there’s all kinds of detail that in the past we’d pick up and then produce traditional looking topographic surveys.” These surveys were essentially 2D drawings with lines labeled as to what they were. “With the LiDAR solution (in the MS50), we’re able to produce a 3D model of the rooftop pretty easily.”
For many clients of his company based northwest of Toronto in Orangeville and Guelph, Ontario, 2D survey plat drawings are still preferred and often a better way of delivering a final product that they can use, Mak says. However, he adds, there is a growing demand for 3D, especially 3D building information modeling (BIM). “You’re getting into merging CAD with 3D modeling and with GIS.” Also, Van Harten increasingly is getting requests from some clients to integrate CAD survey drawings into a BIM model.
For many projects, the combination of the Leica Nova MS50 and MicroSurvey CAD Ultimate software is ideal, particularly when surveying conditions are difficult or even risky.
One that Mak recalls was a slope stability survey for a geotechnical engineer who was planning a development at the top of a hill. The engineer needed to have a detailed survey of the hill’s slope. “It was pretty ugly ground, making it treacherous to even walk around,” Mak says. “We were looking at a crew with a total station set up somewhere and having to walk up and down this slope to get observations for a sufficient visual model of the slope. It was going to take four to six hours, and there was some concern about the safety element over how a person would do this without losing his footing, and slipping and sliding down the hill and breaking his leg,”
At that point, Mak placed the MS50 in a couple of locations where the slope was in view and set it to a fairly high-density scan, because some measurements were intercepted by branches and twigs, and would not reach the ground. In this instance, a four-man team was involved, because one goal was to study the digital model and see how much data was represented at the end of the survey. The survey team’s work was actually a training exercise. “One other person helped by holding the prism pole for the initial resection observations, but after starting the scan, we just watched it work,” Mak says. “The data was substantial, and the whole process of scanning and data collection was much faster than other methods.”
Once back at the office, the MicroSurvey CAD Ultimate program was put to the test. “It was helpful for the slope stability survey, because of a feature called the grid search, where you can define a grid with whatever dimensions you like on a horizontal plane, and then at each grid intersection you can search for the lowest LiDAR data point within a certain radius on that plane.” Mak considers MicroSurvey CAD Ultimate a great tool for finding a unique LiDAR point at the ground level. Once hundreds, thousands or millions of LiDAR points are collected, it’s easy to extract whatever amount of points are needed to represent the ground surface. “And that’s the surface used to generate the 3D model of the ground.”
Fellow Canadian survey engineer Doug Rutherford, of Snell & Oslund Surveys, also uses the Leica Nova MS50 and MicroSurvey CAD Ultimate. Due to the MS50’s unique versatility via robotic total station, reflectorless electronic distance measurement and scanning capabilities, Rutherford’s firm in Red Deer, Alberta, can now run just a one-man crew in the field for survey projects, if needed. In fact, the surveying firm uses the MS50 every day and for nearly all projects requiring site line calculations and property reports.
“Where we would really find an advantage to it is when we do our construction layouts,” says Rutherford, referring to AutoCAD drawing files that can easily be uploaded into the MS50 total station feature. The total station feature extracts the coordinates from the AutoCAD drawings, and then can be laid out in the surveying field of interest. The MS50 and MicroSurvey CAD Ultimate were helpful in this way on two projects that Rutherford cited.
One was a project for Capital Power Corporation, of Edmonton, Alberta, involving the positioning of 83 wind turbines requiring assembly to create a wind farm for renewable energy. The turbines needed to be placed in an exact configuration for the flow of air to be optimized.
Another project required renovating a structure containing an indoor pool at a Sheraton Hotel. Again, the MS50 was used because of its robotic and reflectorless total station capabilities. “We were able to lay out gridlines on the walls of the pool facility walls that needed to be expanded,” Rutherford says. “We used plans provided to us by architects showing the new construction planned for the expansion in relation to the gridlines. Using the MS50 and processing data with MicroSurvey CAD Ultimate allowed us to lay out the control for the new construction in the pool facility.”
These tools proved invaluable because, Rutherford points out, coordinates within the AutoCAD drawings are easily integrated with the MS50 so that they can be mapped. The MS50’s total station feature provides a seamless, robust integration of uploading data in the field, calculating measurements and then exporting them to the MicroSurvey CAD Ultimate software for drafting a final plat.
Rutherford likes the fact the MS50 not only gives Snell & Oslund Surveys the flexibility of running a one-man crew in the field for client survey projects, but the MultiStation along with MicroSurvey CAD Ultimate are also intuitive to use. “Compared to total stations from years ago, these are far ahead in ease of use,” he says. “It doesn’t take long to extract meaningful information out of the scans. We get more efficient workflow.”
Robert Galvin is a freelance writer who covers technology and business trends. He can be reached at firstname.lastname@example.org.