Surveys with a Side of Scanning
WestLAND Group used the Leica Nova MS50 to scan the facades of an office building for CGM Development. The scans were used to create models of the building exterior and surrounding topography as a starting point for BIM.
WestLAND Group, Inc. was founded in 2000, in Rancho Cucamonga, Calif., and is a mid-size, well-established firm that provides civil engineering, GIS, surveying and mapping and planning to clients in energy, rail, construction, municipal, and development. The firm is always looking to adopt new technology and quickly developed expertise in CAD, GNSS, and reflectorless/robotic total stations, but until late 2013, they hadn’t done much with laser scanning. “We’d tried renting scanners, and subcontracting LiDAR work, but it didn’t work out particularly well,” said WestLAND’s Vice-President of Geomatics Mike Angelo, EIT, PLS. “We also found that purchasing a conventional scanner was just not cost-effective, as we did not have scanning projects lined up and it seemed difficult to market scanning to existing clients without an instrument readily available and a workflow in place.”
Laser scanners are big investments, and WestLAND took its time looking for the right solution. The firm had a definite need; the work they do for railroads often calls for clearance surveys around tunnels and bridges, and point clouds and cloud-based models are ideal for this. But there wasn’t a huge demand; buying a dedicated scanner seemed like too much investment. Also, WestLAND’s topographic and as-built survey workflow is already quite efficient; ideally, scanning would fit into and extend this workflow, not be a separate solution with parallel-but-separate field and office workflows.
So Angelo looked with special interest at the first instruments that combined total stations and scanning into one housing. He wasn’t impressed. “The ones we looked at just didn’t provide the speed, point density and precision that we needed," said Angelo. "On the occasions we needed a scanner, we needed a complete high definition solution.”
That changed in December 2013, when WestLAND took delivery of a Leica Nova MS50 MultiStation from James Yaccino of Leica Geosystems. “Frankly, it didn’t cost a great deal more than the high-end total stations currently on the market,” said Angelo. “And the fact that the MS50 is a complete robotic/reflectorless total station that could be put straight to work on our typical topo, boundary, and construction surveys made a lot of sense. When we received the initial demonstration, we could tell that this instrument was the real deal for our regular surveying work and for scanning. I knew we could put it to work immediately in the field, and that we’d be able to create opportunities to integrate scanning into our design and as-built surveys, and that, I felt, would be a great way to market scanning and expand our services into scanning-specific projects.”
After a couple of months working with the Nova MS50, Angelo is confident they made a good choice: “It’s already proved itself to be a very effective scanner—we were scanning 20 minutes after it was delivered—and have now performed several scans for rail, building façade and pipeline as-built surveys. It really is simple to switch from conventional surveying to scanning, and we have found that processing and adjusting point cloud data is a relatively easy extension of our current workflows.”
The Nova MS50 combines a robotic total station with a reflectorless range of 2,000 meters with a built-in scanner that has a scan range of 1,000 meters, millimeter precision, and up to 1,000 points a second. GNSS can be integrated, and the Nova MS50 also has very good imaging capacity and image-assisted documentation.
Since acquiring the Leica Geosystems instrument, WestLAND has been in the same position as any firm that has just made a big investment in capacity; they’ve been learning to use the Nova MS50 on the job, finding ways to use the new data forms, and looking for opportunities to market their new deliverables. Three early projects managed to do all these things at once and are excellent examples of how to get started scanning.
The First Tunnel is Free …
A month after the Nova MS50 was delivered, J.L. Patterson & Associates (JLP), a rail-specialized engineering firm, came to WestLAND and requested ground control for a mobile LiDAR survey. “They’re sophisticated users of 3D spatial data,” said Angelo. “What they wanted in this case was for us to set control along and within several railroad tunnels near the Mexican border, and someone else would be doing the LiDAR work.”
JLP was used to working with point clouds, but didn’t necessarily think of WestLAND when it came to having scanning capabilities. Angelo proposed that his firm not only provide control, but, “while we were out there…” scan one tunnel, and see if the deliverable worked and was cost-effective. The offer was accepted, and Angelo got started.
The work was ultimately for Pacific Imperial Railroad (PIRR) on a section of rail known as “The Impossible Railroad.” PIRR is rehabilitating the Impossible Railroad for use with double stacked trains, and 17 tunnels will have to be surveyed for clearance analysis and possible grading and track redesign. Angelo viewed the scan of one tunnel as basically a marketing investment: “I offered to scan one of the smaller tunnels, No. 15, which was just 300 feet long. That was our first project use of the MS50, and it went very well.”
While traversing through the tunnel using the Nova MS50 for the control survey, the instrument was switched to scan mode and, since it was already on basis, started the scans immediately. Just a few setups were needed, and scanning the entire tunnel took just a couple of extra hours in the field. “The scanning time actually fits into our day nicely,” said Angelo. “It gives us time to clean up our notes and sketches, and take pictures of the site to supplement the MS50’s images.”
In the office, Angelo says the Leica Infinity software has become invaluable: “It’s easy to use and quite impressive. We’re able to import and view the raw survey and scan data easily, and we can do a network adjustment to tighten up the precision of our control traverse, along with the corresponding conventional survey points and point cloud data. We’re then able to export all of the data into multiple file formats to be imported directly into MicroStation, AutoCAD Civil 3D, and/or Revit, depending on the particular project and deliverable requirements.”
In this case, WestLAND Project Surveyor Travis Mensen used Infinity to process and adjust the point cloud data and exported it to Bentley MicroStation V8i to create longitudinal breaklines along the rails and tunnel, which had a trapezoidal cross-section. He then created a MicroStation 3D deliverable according to the project specifications. All the point cloud processing work took about a day. Angelo used the information gained from this pilot project to prepare a proposal for the remaining 16 tunnels: “J.L. Patterson liked our proposal and said our work was effective for the clearance analysis and design work. We expect to get the project when they get the go ahead from the client.”
A Building and a Bridge
WestLAND’s second scanning opportunity came from an existing client ... CGM Development located in the City of Industry in Southern California. CGM asked for an as-built survey of an office building, to support redevelopment as a condominium. Angelo surveyed the building interior and submitted a condominium plan. He was then asked to provide a survey to support redesign of the exterior for ADA compliance and facade renovation. “Again, we were going to be there anyway, so I decided to scan the facades,” said Angelo. The client wasn’t paying, specifically, for scanning. However, Angelo had already learned that he could perform and process scans quickly; on this project, the Nova MS50 was used to provide a much better deliverable with small extra investment in time … and the client was delighted. It also gave Angelo the opportunity to see how scanning would support WestLAND’s BIM work.
“We did not actually create a complete BIM model,” he said. “That would typically include a complete intelligent 3D model of the building exterior and interior with utilities, walls, structural components, etc.” Instead, after processing the point cloud in Infinity and importing it into Revit and AutoCAD Civil 3D, WestLAND Survey/GIS Analyst Matt Corcoran modeled and rendered the building exterior and surrounding topography, and provided a deliverable to the project architect that was created in the familiar native Revit environment. Basically, the idea is to scan existing buildings when appropriate, and deliver the data to the design firm as a starting point or “shell” for an actual BIM model. In this case, Angelo says the client loved it: “They were able to use our data for design and for presentation purposes. We expect them to ask for similar models when requesting work for future projects.”
WestLAND’s third project started with another request from JLP. They asked for an obstruction/clearance survey of an existing bridge, together with surrounding topography along existing tracks in a railroad yard. WestLAND had done similar projects for JLP, but this time, thanks to the good outcome of the PIR tunnel project, scanning was specified.
Angelo says the fieldwork was straightforward. “We had to set up on both sides of the bridge anyway, for control and conventional topo, so the additional scanning only took about an hour,” he said. “This time, we performed a total of four scans, 5-15 minutes apiece depending on density, from setups we were using anyway. We also took reflectorless shots on key features—we compare these to the point cloud for QA/QC purposes, and everything is always within three hundredths of a foot or better.”
After that, the entire project — point cloud, control, and topography — went straight into Infinity for adjustment and then into MicroStation V8i (JLP’s preferred CAD environment) for line work, breaklines and contours. “It only took about an hour to review and incorporate the point cloud into the drawing,” said Angelo. It was a good example of a pilot project paying off with new work.
Angelo says the Nova MS50 lives up to the claims: “After a few hours training from Leica, we were able to get to work immediately on actual projects and provide high-quality 3D deliverables with minimal extra time. Processing all the points we gather, in one environment, is a real time saver. We’re looking forward to using it more. We’re already under contract to provide an as-built of a pipeline network located in a steam power plant; that’s work that would be very difficult for us to perform cost-effectively without scanning capabilities.”