Drone solar land survey data prevents construction errors on flooded Illinois soil

When an energy firm needed a site-plan map for a solar farm at the southern tip of Illinois in late 2019, they turned to Bacon Farmer Workman Engineering and Testing, Inc. (BFW). Priding itself on being a “one-stop-shop” for full-service engineering excellence, BFW gladly accepted the project.

Yet they quickly ran into a couple of challenges that only WingtraOne could handle. First, the survey site sat where the Mississippi and Ohio rivers combine, creating highly-fertile but sometimes impassable wetlands. Second, this was the wet season and the deadline for this large survey was tight.

“The problem was, we couldn’t access it with a utility task vehicle (UTV),” Jacob Cash, BFW’s Mobile Mapping and LiDAR Department Manager explained. “We tried to walk it, and by a few thousand feet, our surveyors were unable to go on.”

Impassible floodlands during the wet season; tight deadline; large survey area, limited take-off and landing space

So when my survey manager asked me for a 1700 ac (690 ha) aerial map, I knew it was only possible with WingtraOne and that I could give him a lot more detail.

Jacob Cash
BFW Mobile Mapping and LiDAR Department Manager

Finding the right drone for professional land surveys

Cash has been with BFW for more than 15 years and has been land surveying since he was 16. He’s seen a lot of changes in technology, including a quantum leap in data capture when he started using drones a couple of years ago. The first drone that the company tried was a DJI Matrice. They used it for smaller areas to measure volumes and then began taking more complex projects.

“There was a 700 ac (280 ha) flood study project that we tried with the Matrice that took a really long time,” Cash said.

BFW team with WingtraPilot
Cash and BFW colleagues with the WingtraPilot during a WingtraOne mission.

We got results, but we also realized there was a lot that we wanted to provide for our clients that the Matrice just couldn’t handle.

Jacob Cash
BFW Mobile Mapping and LiDAR Department Manager

1700 acres of wetland drone surveying


WingtraOne icon
6 hrs
+ 12x set-up time*
Field days

Matrice 210

Matrice 210 icon
15 hrs
+ 30x set-up time*
Field days

Conservative estimates and calculations based on provided flight times and coverage times from both drones provided by source. *Set-up time, according to source, is considerably less per flight for WingtraOne due to easy two-part assembly and smooth portability of drone.

What about fixed-wings?

The BFW survey team then tested a fixed-wing drone, but through many trials, Cash said the level of instability during take-off and landing caused concerns about safety and reliability. That’s when they found the WingtraOne. And when they did, they tested it thoroughly.

Since they handle large-scale, industrial and infrastructural projects,  survey sometimes involve plants employing people. Cash said the drone they’d choose to work with must be safe and reliable. They soon discovered WingtraOne was the best choice for all of their needs, including safety.

With the WingtraOne, I tell all of my clients who ask about safety issues that I can hit that transition and set it straight down on the ground.

Jacob Cash
BFW Mobile Mapping and LiDAR Department Manager

Money saved and ROI with WingtraOne

Savings to the client

money saved illustration

Client saved almost half the cost on their survey compared to traditional methods.

Savings to the contractor

money saved illustration contractor

BFW earned 40 percent more in profit for a set amount of hours to do the job.

Direct drone ROI

direct drone ROI for WingtraOne illustration

The profit margin on this one job covered almost all of the cost of WingtraOne.

Drone surveying in the windy season on the open plains

To get started with the solar farm site-plan aerial survey, Cash coordinated with the ground crew to set up some targets to establish elevation. Flying the area with the WingtraOne took about six flight hours over five days due to the short time windows available each day under the conditions. “Not only was it the wet season, but it was also the windy season,” Cash explained. “And this is wide, open, flat and it looks like you’re in Kansas. So every time we’d go there, I’d look at my weather app and say ‘okay we’ve got three hours to fly.’ And there were a lot of times where I really pushed the envelope with the Wingtra.”




The survey, flown with the Sony QX1 payload, enabled rich outputs via several software programs, including Pix4D, with an average accuracy of 4.5 cm (1.8 in). Factoring in the accuracy of the ground measurements, Cash was confident with the results and happy with WingtraOne’s coverage and efficiency.

“Our survey guys were out there using a pole, and it was very muddy. And I was thinking ‘did they just stick it right on top of the mud or did they stand there and let it drop down and take a shot?’”

We needed to provide our client with accurate data. And that’s where photogrammetry really shines. It reads the top.

Jacob Cash
BFW Mobile Mapping and LiDAR Department Manager

Wingtra-one data based orthomosaic, 3D and color-coded elevation model outputs of the 1700 acre (690 ha) solar land survey area. With the QX1 payload, they were able to achieve 4.4 cm (1.75 in) absolute accuracy at the product stage, a result Cash and BFW’s clients were excited to work with.

Avoiding costly construction mistakes with the right survey tools

Before the survey began, BFW’s client already had ideas about where all of their panels and equipment would be placed during and after construction of the solar project. But from the digital terrain models based on the WingtraOne survey data, Cash was able to offer them more insight than they expected. This likely cut countless costs in time and money.

The client saw from the elevation maps where the solar farm would most definitely flood, so they rearranged their construction plans around the areas that would stay dry all year round.

They saw the visual representation and realized ‘that’s where the elevation drops off, and we’re not going to be able to put anything down in there.’ So we really gave them a good glimpse of the why and why not.

Jacob Cash
BFW Mobile Mapping and LiDAR Department Manager

“Worth its weight in gold”

Rich drone data like that captured by WingtraOne is changing the way surveyor jobs are priced. The larger the scale, the more dramatic the saving potential for both the contractor and the client. This is because the client pays for data capture up front and then saves on analysis over the long run.

“It used to be the case that there would be a landmark, like a manhole, that was missed in a survey. And they’d need the location of it, so someone would have to drive out, set up equipment and get the coordinates of it. With this technology, we don’t do that anymore. I just get a call or an email and someone says ‘hey that manhole, can you give me an x,y,z on that?’ And in a matter of minutes, I can.”


“Really when they see the big picture, the WingtraOne is worth its weight in gold. Once you explain that to them they’re like ‘okay I’m sold, let’s go out and get this done.”

Cash said that in the case of this solar land survey, the cost to the client ended up being around half of what it would be for just capturing the data using traditional methods. On top of that, the data from WingtraOne is richer in data points and details. In this case, these details saved the client immeasurable costs in damage control. Best part of all? The savings work both ways:

“We made a 40 percent profit on what I charged compared to what I did,” Cash said. “Not only are we doing this faster, but this gives us the ability to assign the field crew to do other things while WingtraOne captures data on large areas, quickly.” 

As for the cost of the WingtraOne drone itself, Cash explained:

Even though we made an investment in the WingtraOne, we’re paying it off so quick. This job alone covered the majority of it.

Jacob Cash
BFW Mobile Mapping and LiDAR Department Manager

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