Early in 2012 Precision 3d Scanning was contracted to scan Camelback Mountain on behalf of CK Engineering and the City of Phoenix. For those unfamiliar with Phoenix, Arizona, this is the small mountain range that is considered the crown jewel and is in the center of the 5th largest city in America. It was the home of the prehistoric HoHoKam Natives and today serves as the most popular hiking destination in Arizona with more than 300,000 hikers converging on the 3 mile trail each year.
There were multiple goals for the scan data. First of all, as one of the City of Phoenixs most popular assets, they want to identify the as-is condition of the existing trail system. They wanted it in 3d so it was an intuitive look at the mountain and trail system. This allows the City to monitor and maintain the mountain for generations to come.
Secondly, the use of terrestrial LiDAR was implemented because of the cost effectiveness, combined with being able to cover the many small ravines and rock features of the mountain. To have completed this from an airborne platform was simply not efficient or economical.
Finally, to be able to stitch together different point clouds on an as needed basis was significantly advantageous to the client. In effect, data can be added over time to capture new areas of particular interest. This allows areas of Camelback to be continually updated and analyzed. In effect, a continuous living model can be created.
The project was completed with 2 Leica C-10 time-of-flight scanners, selected for their speed and range -it was the ideal laser scanner for the project. With each scanner was a 2 man crew that set control and targets, and then leapfrogged from the summit all the way down to each respective parking area. We also enlisted the help of several regular trail hiking volunteers who wanted to assist in the preservation of their mountain. And of course we had professional surveyors set control.
There were many challenges. Carrying a $100k instrument around the mountain, in and out of a backpack, along with the tripod was very tiresome. Much of the trail is very steep with 60 degree slopes and imbedded handrails to assist hikers. Some trail sections require hikers to use their hands to ascend/descend the slope. In other areas of the mountain, its not uncommon for gigantic boulders to pose obstacles or wander into areas with exposed cliffs that have 500 drops. The terrain is very rugged, desert landscape with brush and rock formations that posed challenges with the lines of site. As such, many scan positions were required to capture the accurate topography.
The scanning was done in daylight conditions to allow the crews to accurately see the terrain. But with the nearly 2,000 hikers per day on the main trail, many of whom were very curious and couldnt resist touching the target spheres, it became difficult to marshal the trail and complete the scanning.
And finally there was the conditioning element. Frankly, some of the scan technicians hadnt signed up to blanket an entire mountain from every possible steep elevation angle, work long hours, and do it in 90 degree temperatures. It was in many ways a very dangerous scan project.
During the second week into the laser scanning process the tripod wed been using had become a little worn from the continuous deployment in the rugged terrain. One of the crews set the Leica C-10 on the legs and turned his back. Nobody is really sure if it was an invisible force of nature, or the ghosts of the HuHuKam Tribe that had inhabited the area years earlier, but the scanner took a tumble down a 22 cliff. If you were wondering how well a scanner bounces down a mountainthat answer is not good. And they have a tendency to make a loud bang as they bounce off rocks before settling comfortably on the trail below.
The crew was sick to their stomach and even more so thinking about having to report the incident to management. That theyd just booted the six-figure instrument down the mountain wasnt a phone call either wanted to make. Photos were taken and the pieces of the scanner collected and returned to the shop for analysis. The remaining crew with their working C-10 said their goodbyes to the crew that dropped the scanner, secretly wondering if theyd be employed tomorrow. In fact, they offered to help them update their resumes. (The crew was not fired. With the amount of travel and work completedits surprising that a scanner hadnt been dropped already.)
Upon returning to the shop, and to the credit of product engineers at Leica, the unit actually turned back on and all the scan data was intact. Furthermore, although the housing was crushed, the scanner actually worked.
All the Camelback scan data was taken into Cyclone for processing. A significant amount of time was spent cleaning up the data (removing hikers, vegetation, etc.) so that a true 3d model could be constructed. There were several deliverables including a CAD model, mesh model, 2d topo map, and theres discussion of creating a phone app for hikers to download.
With laser scanning becoming more cost effective each year, more projects like this will emerge. The fact that data can be collected accurately and taken into a 3d model has tremendous benefits for a wide range of industries. Today its estimated that less than 2% of all potential scan projects implement laser scanning. As the world continues to integrate new technology, projects like Camel back Mountain will become more common.
To learn more, please visit our website at www.precision3dscanning.com