UAV’s In Geographical Research

UAV complied image

Droning On – As I write, our departmental UAV has just returned from fieldwork in Cambodia, mapping landforms peripheral to the the Mekong River. See the Stellar website for more info on that project!

In this post I’ll explain what the state of the art of civilian survey UAV’s (“drones”) looks like,  how UAV technology is changing the way we go about acquiring geospatial data, and what the specific requirements of our research means for the design and use of this technology.

The Birds – There are a number of systems on the market, some from established survey companies such as Trimble, but the majority from start-ups based in Europe and North America; they can be broadly split into fixed and rotary wing types. The payloads are usually visible-light or multi-spectral imaging equipment, but there is no reason why other instrumentation couldn’t be fitted. Our solution is the QuestUAV200, which acquires plan-view imagery. The systems are capable of autonomous flight, following a pre-programmed route and making corrections to stay on course, using on-board GPS, pressure, speed and inertia sensors. Take-off and approach are also often automated, with take-off usually by way of sling-shot. The final landing phase is commonly semi-automatic but controlled by the pilot – this manual control can be taken at any point in flight. Telemetry is almost ubiquitous, with a tablet or laptop displaying positional and sensor data, although these systems do not have the bandwidth to display real-time imagery.

Me and the UAV

Smile For The Camera! –  Before UAV solutions, aerial imagery was available from two sources – manned flight or satellite missions. Manned flights are expensive and logistically difficult to fly often – satellite data can have good temporal resolution but poor spatial resolution. By using UAV’s we can acquire data that is both spatially and temporally more detailed than either of these sources. In addition the ability to provide overlapping and oblique imagery aids the production of detailed digital elevation models. However, this is all at the cost of coverage – the legal restrictions on flight distance means coverage of each flight is restricted to about 1.2 square kilometres.

Brace for Impact – Our research has led us to deploy our UAV in Iceland and Cambodia, where using complicated, delicate kit in extreme or remote environments offers some unique challenges. We require equipment that is either very robust (difficult to achieve for a UAV!) or easy to service in the field. The QuestUAV has an airframe that can easily be repaired in the field, and a protective cover that protects the camera when landing in a snowfield or rice paddy. The system is also entirely battery powered, and the running time for the system can be expanded with the purchase of additional aircraft, laptop and camera batteries.

In summer 2013 flights were made in Iceland to survey part of a glacier and the associated foreland. The resulting DEM’s and associated imagery have allowed for very detailed geomorphological mapping. The DEM’s of the glacier itself will be used as part of a long term glacier velocity mapping project. The system has applications throughout physical geography fieldwork, including data collection on peat bogs, rivers, glaciers, lake catchments, and archaeological sites.

UAV land1

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The New Forest: research on our doorstep

Of all the locations where the members of PLUS conduct their fieldwork, mine is almost certainly the least far flung – my research is based in the New Forest National Park, in the county of Hampshire in south-east England.

Undertaking fieldwork in a Park whose nearest border lies a mere six miles (9.7 km) from the University of Southampton’s main campus, has at times seemed somewhat unexciting and undeniably less than exotic. However, whenever I have entertained such thoughts, I have fallen into what I believe to be one of the major pitfalls of working so close to home – taking things for granted. I have at times harboured dreams of carrying out research somewhere ‘more interesting’ and occasionally, I admit, jealous thoughts of those who do, all the while failing to fully appreciate the amazing scenery, wildlife, culture and history that surrounds me.

So, I decided to fully embrace and enjoy my fieldwork in the New Forest, and recognise how fortunate I am to have the opportunity to spend so much time there. And it is a great place to do fieldwork. First of all, it’s ONLY SIX MILES from the University of Southampton’s main campus! So I can pop out there whenever I like. Very handy for taking advantage of good weather or remedying the odd bit of fieldwork gone wrong.

Secondly, it is a very beautiful place. I have, in the past, visited quite a few ‘exciting’ and ‘exotic’ places around the world, and the Forest can compete with the best of them in terms of views, particularly on a sunny autumn day when the trees are changing their colours. I carry out fieldwork all over the Park, and so have the chance to admire its ancient woodlands, heathlands, mires and rivers as well as all the flora and fauna they contain.

Then there are the people. Lots and lots of people. The thing that surprised me most the first time I visited the Park more than two years ago, on a very hot Sunday in October, was the sheer number of people who come here all year round to enjoy all that it has to offer. It wasn’t what I expected. But I have grown to appreciate the role of people in the Forest (it is after all the main focus of my research: human-environment interactions), and how fundamental they have been in shaping this area and in creating the cultural landscape that we see today.

So, I count myself lucky to have spent time in such a place, and very much look forward to the days of fieldwork to come.

Lake coring in the South Seas

Bleary eyed I walked off a plane onto Samoan soil just ahead of two of my supervisors, Prof. David Sear and Dr. Pete Langdon. It was around 6am and the first thing that hit me was a wall of humidity and the surprising lack of flies. Traversing through the airport we were welcomed by Samoans singing and playing guitars, immediately highlighting that I was in a very different place to anywhere I have been before. After David got the keys for the rental car, we drove along the coastline as the sun broke the horizon. Passing the local homesteads called Fales, we entered Apia (Samoa’s capital)and then took the main road that cut across the country. With the Sun blazing in the sky we came across our first magnificent natural wonder: a waterfall cascading into a deep ravine.

We then met Josie: our guide. She was incredibly friendly and welcoming, introducing us to the ‘boys’ who would help us over the next few days. With the assistance of Lucy and Anushka, Josie served us with a much needed breakfast on a veranda overlooking the picturesque Samoan coastline.

Beginning a little later than expected due to the never-ending rain we set off on a hike to the lake. We hiked through an overgrown grassy track, entering the jungle proper after overcoming obstacles akin to a Total Wipeout slalom. Needless to say that the boys – being ridiculously fit like most Samoans – charged off to the lake with our kit. Bright red flowers lined the track; trees soared into the sky; a bright orange mud lay beneath my feet that managed to get on virtually all of my clothes. For nearly two hours Pete, David and I hiked with Josie to the lake, finally gaining a view after fighting our way through dense vegetation. Simply, the first view of the lake was magnificent. Hidden away inside the crater of an extinct volcano all you could see was this near-perfect circle of green water. After gawking for a bit and appreciating where we were we began the work.

This started off with assembling a raft from various materials – a key component being tire inner tubes. Admittedly there were a few minor hiccups along the way: one being that an inflatable boat we had hoped to use had various holes in. The boys really proved their worth making the raft; never complaining, they really helped make what could have been an arduous task fun. Once the raft was built Pete and I rowed out, taking measurements of the lake’s depth so that we could gain an understanding of the lake’s bathymetry and determine where the deepest point was for coring the following day.

It wasn’t until the following day that we really got down to what we had come to Samoa to do: obtain lake sediment cores from Lake Lanoto’o. David, Pete and I rowed to the deepest part of the lake with all the kit – no easy task! – and worked as a team to obtain as long a core as we possibly could. After doing all of the necessary tasks to get our first core, we carefully brought up the corer to the surface. With trepidation, and much excitement, the core was extruded from the corer – we had mud! We repeated this process a few more times, eventually getting just under two metres of sediment. Sadly more couldn’t be obtained as several of the coring rods broke. I spent the following day cleaning the cores and logging their stratigraphy, taking samples at one centimetre intervals after I had done this. You would be surprised at how long it takes to do this – an entire day!

It wasn’t all work, though. On our final day in Samoa we visited Samoa’s version of a duck pond: a turtle pond. One of the most surreal moments of the trip was standing by the edge of this pond feeding the turtles a loaf of bread bought from a nearby store. I also went snorkling for the first time. Swimming along Samoa’s coral reef, admittedly fighting against a pretty strong current, I witnessed all sorts of weird and wonderful fish. The real highlight of the day, though, had to be the dinner Josie, Anushka and Lucy prepared for us on our final night. Cooked in a traditional Samoan stone oven, tuna caught that morning was wrapped in banana leaves and slow cooked. I’ve honestly never tasted better tuna in my life. We were also served taro, a vegetable that is a Samoan staple, as part of the meal. If you’re ever in need of being filled up with as little food as possible then taro is your answer.

David and Pete continually said to me that it’ll probably be the best fieldwork I will ever experience; I think that I have to agree.