This method allows for better survey coverage of the rock slope than photos previously taken along the highway by hand. As with the manual photos, he overlaps each photo with the preceding shot.
Exp’s governmental customers typically markup photos of the rock slope with lines drawn to indicate the outline of where they want the mesh. Lepine then makes a 3D model of the mesh using the surface drawing tools in PhotoModeler. At this point, the model is exported to AutoCAD Civil 3D where Lepine calculates the area of each section of mesh, creates annotations and generates separate surface models of each mesh. These deliverables are then provided to exp’s client.
Sometimes the client requests modifications and when the client is satisfied Lepine produces a final drawing that is included in the package provided to the contractors for bidding. Often, when the construction is being performed, contractors may propose changes, such as extending the mesh to cover additional areas of the rock slope. In this situation, exp returns to the site after the construction is completed and performs an as-built survey using PhotoModeler that is used to determine the contractor’s payment.
Environmental monitoring and research
Matt Sakals’ work for FLNRO involves environmental research and monitoring in support of ecosystems that may be impacted by natural or human-related events and structures such as landslides, dams, and mining sites. In one case a rockslide in a remote canyon created an obstruction in a river with a large salmon run. The smaller salmon could get through the obstruction but the larger fish had to be netted and flown by helicopter past the blockage as a temporary measure. “Photos of the obstruction and surrounding area had been taken from a helicopter but they did not provide the complete understanding that was needed to plan remediation operations,” according to Sakals. “Our capability for acquiring survey data via photogrammetry in rugged areas with limited accessibility provided a solution.”
Working from the top of the canyon, Sakals flew his UAS at eye level up and down the canyon. The photographs taken by the UAS were to support the investigation into a possible plan, which was to wait until the river froze, then drive an excavator over the ice to clear the obstruction. The photographs showed the gravel bars where the river is shallow. Knowing the location of these bars was important because the planners wanted to
Aerial view of a debris slide catchment area. This photo shows the catchment area before the contractor has removed the debris and is one of many that will be imported into PhotoModeler to calculate the total debris volume of the slide.