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“Waste… waste is the worst part about construction! If equipment is not running or people are waiting for information to get started, we lose money. Changing this is what motivated me to start a career in the construction business,” explained Colin See, when asked why he started to work with Bogh Engineering and use drones for construction.

Colin is currently studying construction management at the University of Redlands, and he interns at Bogh two days a week. When Mark Bogh, owner and 30 year industry veteran, purchased Site Scan, he immediately advised Colin to take the FAA Part 107 remote pilot test and get certified to fly drones on-site. “When we introduce a new technology at the company, I want one person to initially own it. Colin was the perfect fit. Eventually, my goal is to have everyone at the company instructed to use any tool we have.” Mark said.

For Bogh, the advantage of drone surveying is the speed and frequency of data collection. With traditional topographic surveying, they needed two days of lead time and 1–2 days in the field to collect the data. Additionally, they had to manually process the data in Civil 3D, pushing back the final deliverable so it was only ready a week after it was initially requested. “With Site Scan, I can tell Colin to fly a site in the morning and we have the data completely processed in the afternoon,” Mark said. Our success story goes in-depth into how Site Scan helped drive ROI for Bogh.

The first assignment for Colin

One morning in February 2017, Mark asked Colin to survey the Indio High School construction site before the company started grading. He arrived at the site at 9:00 am, and before flying the drone he measured ground control points (GCPs) so that the drone data could be georeferenced and used for cut-and-fill analysis. The GCPs had already been marked on the ground with an orange X in an earlier phase of the project, so all that Colin had to do was walk to the marked signs and measure the coordinates of each point with a total station [Image 1]. To walk throughout the 17 acre site and collect the coordinates of all 10 GCPs took Colin less than half an hour.

Image 1: Colin measuring the coordinates of GCPs before the drone flights.

At this point, Colin informed the other construction crew members that he was about to fly the drone. He opened the hard case in the back of his truck, took out the Site Scan drone, started mounting the propellers, and inserted the charged battery. He then turned on the drone, the controller, and his iPad. In less than a minute, Colin connected and started planning the flight.

Image 2: Colin mounting the propellers on the Site Scan drone.

On this day, he was assigned to collect data for an orthomosaic view and a 3D point cloud, so decided to fly a crosshatch survey to do so. He opened the Site Scan Field app on his iPad and selected the crosshatch flight mode. In this mode, the drone flies two autonomous surveys perpendicular to each other, with the camera pointed at an oblique angle. This ensures the collection of the highest possible detail and oblique images for the 3D model. He used the iPad to select the area he wanted to fly with a couple of taps on the mission planning screen [Image 3]. From the preloaded Google Maps, he immediately recognized the site and had no problem identifying the area he needed to survey. The app automatically calculated the optimal flight path to cover the area Colin selected.

Sample crosshatch flight on the Site Scan Field app

The flight

Liftoff with Bogh Engineering

To start the flight, Colin positioned the drone 20 feet away from his truck, stepped back a couple of feet, and tapped “Fly Survey” on the iPad. The drone took off and follows the planned path. Some construction workers close to Colin followed the drone in the sky, but with graders and dozers running, almost no one else noticed the drone. Colin kept an eye on the drone and monitored flight progress on his iPad.

Image 4: Colin monitoring the drone flight on his iPad.

Given the large area and the fact that the drone needed to fly two perpendicular surveys, the app indicated that the flight needed 3 batteries to complete. Once the first battery ran too low, the Site Scan app notified Colin and the drone automatically flew back for the battery exchange. He went back to the truck, picked up a charged battery from the case, and returned to the drone, which had just safely landed.

Image 5: Replacing the battery and automatically resuming the flight

Completing the survey

He swapped the batteries, powered the Site Scan drone up again, and tapped “Continue Survey” on the iPad. In less than a minute from when it landed, the drone was back in the air and continuing the survey as it left off. Colin repeated the same steps one more time before the drone finally completed the survey. In total, the scan took approximately 35 minutes to complete, and it captured 410 images.

After the final landing, Colin brought the drone back to the truck, unscrewed the propellers, and downloaded the images from the drone to the iPad. This was done with a simple tap on the “Download Images” button. The images were then wirelessly transferred to the iPad [Image 6] without using any SD cards, and the operation took about 10 minutes.

Image 6: Images are downloaded from the drone to the iPad wirelessly with the tap of a button

At this point, all of the necessary data has been collected and secured. Back in the office, Colin uploaded the data to the 3DR cloud for processing and finally handed the orthomosaics and 3D point clouds over to the staff engineer for analysis. “We are looking for an LTE card for the iPad, so that we can already upload the data while I’m still in the field. This would make it even quicker.”

It’s 10:15 am. Colin’s phone rings, and it’s Mark calling. “I have to survey a site in Beaumont before lunch. I’m heading over now. Do you want to join?”