Friday, October 28, 2016

Aerial drone survey work reduces time in the field

by Bart Treece

Nowadays, when someone mentions drones, also known as an unmanned aerial vehicle (UAV), usually it’s in the context of some cool video that makes its way around the Internet. Remember our look at the inside of the new SR 99 tunnel now under construction in Seattle? As a transportation agency, we see other uses for drones that can help us complete work faster, and safer. This was the thought behind a recent test we conducted that used a UAV to survey a section of highway along the coast in Pacific County.

A drone’s-eye view of Washaway Beach, where the ocean is threatening a stretch of SR 105.


There’s a stretch of State Route 105 south of North Cove that is infamously known as “Washaway Beach.” Over the years, extreme coastal erosion has claimed the buildings, roads and infrastructure of a community that once settled at Cape Shoalwater. Each year, the ocean continues to encroach closer towards the highway and threatens to undermine the road. The time has come for us to armor the road and keep SR 105 protected, but before we can begin design work for our project, we need to update survey data to map the physical area.

A drone measures the height of various areas around SR 105 near Washaway Beach, which
we then compared to measurements taken from the ground to compare accuracy.


We’ve been fascinated by UAV use, and with the advancements in technology, we decided give the drone a trial run to see how it compared with our last survey utilizing traditional methods. We hired a consultant to fly a fixed-wing UAV over a preprogrammed route to capture hundreds of photographs, which were stitched together and assigned geographically referenced data points to create a 3D map, known as an orthomosaic aerial photo survey. We found this data to be highly accurate, so much so that we can import it into our computer system to begin design work. The hour-long flight provided as much survey data as a ground crew could produce in a week.

Each year the ocean moves closer toward SR 105 in Pacific County and we're
working on a plan to protect the road against the erosion.
Here’s what we learned:

Benefits
  • Safety – There is no risk to our survey crew
  • No impact to drivers – There was no need to close lanes on the highway
  • Information available sooner – Less time to compile data from the field
  • Costs – There is potential for large cost savings for survey work
  • Quality – Superior, up-to-date aerial photographs and 3D maps
Limitations
  • Staffing – An FAA certification is needed for the remote pilot in command, we hired a consultant
  • Large areas are difficult – The pilot is required to maintain line of sight with the UAV
  • Birds – While this did not happen to us, birds have been known to attack UAVs
  • Weather – Accuracy is diminished by rain or snow
  • Vegetation – Brushy areas and trees can compromise survey accuracy
Where do we go from here?
That’s a great question. We are evaluating the long-term benefits of hiring out a consultant for future projects or purchasing the equipment and licensing our existing staff. Either way, it looks like there’s more drones in our future.

2 comments:

Romilda Gareth said...

thanks

Michael Reif said...

Those little toys helicopters with cameras and wifi they sell at Target and Radio Shack sure are cool.

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