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Mapping Antarctica

Antarctica is among the most poorly mapped places on Earth. So how is British Antarctic Survey’s mapping team expanding our knowledge of the world’s last great wilderness, and what can mapping teach us about how the continent is changing?

In the UK, it’s easy to take maps for granted. For the past two centuries, Ordnance Survey has charted every inch of the country, mapping more than 440 million different features of the British landscape. By contrast, in mapping terms huge swathes of Antarctica are more like a black hole than a white continent.

According to Dr Adrian Fox of British Antarctic Survey’s Mapping and Geographic Information Centre (MAGIC): “It wasn’t until 1983 that the first broadly accurate map of Antarctica was produced. That was the first time a map brought together enough information for us to be pretty sure that we’d got all the major features in the right places.”

The reasons why so much of the highest, driest, coldest and windiest continent on Earth remains so poorly mapped are obvious. Antarctica is truly huge. It’s 58 times the size of Great Britain, so it’s a colossal area to cover. It’s got a relatively short history of exploration and hasn’t had the mapping resources spent on it because it’s an empty mountainous continent that is difficult to work in and is a long way away.”

But these gaps in our knowledge matter. Long acknowledged a superb natural laboratory, Antarctic science has become even more important in an era of rapid climate change. And without accurate maps, both doing and representing science is impossible.

“We produce maps for a variety of purposes — for logistical and operational use, for scientists to use in papers, general purpose maps as an overview for staff and for general sale. There are an increasing number of tourists going South and our maps are very popular,” Paul Cooper explains.

Mapping for science

Although MAGIC can produce maps of the quality Ordnance Survey users expect, it has to target limited resources wisely. Its most detailed maps include areas of the Antarctic Peninsula — BAS’s main area of operation — such as Rothera Research Station.

According to Adrian: “This area is heavily travelled so we need the best possible map to allow people to travel safely and plan their science. Based on our own aerial photography and GPS work, our Rothera Research Station map sets the bar for 1:50,000 or 1:25,000 topographic mapping in Antarctica and won a prize in the 2007 British Cartographic Society map design competition.”

MAGIC also plays a key role supporting BAS scientists in the field. “Our main bread and butter work is using aerial photographs, maps and satellite images to support BAS’s science and logistics programmes — our work helps make them more efficient,” he says.

“For a field party of a geologist and mountaineer going somewhere in the back of beyond, we’d make them a map so they could plan their project, travel safely in the field and then use it to plot their results when they get back. We also gather information to help them with their science. Last season we flew aerial infrared photography, which is fantastic at showing up vegetation, so it will help BAS’s terrestrial biologists chart changes in Antarctic vegetation.”

And because BAS’s operations cover such a large area, MAGIC’s work is also vital for the BAS air unit. “If you transposed BAS’s operational footprint to Europe it would extend east of Moscow and as far south as Turkey. We cover this with twin otter aircraft, operating on piles of fuel drums and landing on skis, so several times a year we produce a map for the air unit marking places that they might visit during the field season — places like fuel depots and automated weather stations — and giving distances, flight times and fuel burn. It’s a classic example of using a map to solve a real operational problem,” Adrian explains.

Mapping as science

But MAGIC’s mapping isn’t only about supporting other BAS scientists. Aided by new technologies such as satellite imagery and other geographic information systems, mapping is producing increasingly innovative and important science in its own right.

In 2007, after teaming up with NASA and the US Geological Survey, MAGIC unveiled something called the Landsat Image Mosaic of Antarctica (LIMA). Based on over 1000 scenes taken during seven years of satellite observations, LIMA is the most geographically accurate, true-colour satellite photograph ever made of Antarctica.

While stunning to look at, LIMA’s real value lies in its potential to revolutionise science in Antarctica. According to BAS’s Andrew Fleming: “LIMA is a step change — we’ve gone from a continent that didn’t have any continuous mapping to a geometrically-correct dataset, so you’re able to see details that haven’t ever been glimpsed before.”

Thanks to LIMA, scientists at BAS have already produced ground-breaking work mapping emperor penguin colonies. And because it’s the first “time-stamped” overview of the continent, LIMA provides an important baseline for monitoring the impacts of climate change.

New technology such as satellites is also giving BAS’s archive a new lease of scientific life. For MAGIC staff, BAS’s archive of thousands of aerial photographs, surveyors’ notebooks, hydrographic charts and old maps dating back to the 1940s is a unique resource.

As Adrian explains:

“The aerial photographs were taken for mapping purposes but we’re now using them to look at how Antarctica has changed. What’s interesting is this recycling of material that was collected for another purpose. It had its original value, which was to make a hydrographic chart, but it has a secondary value, unthought-of at the time, which may be even greater.”

The MAGIC team has used the archive to great effect, making major discoveries about how far and fast glaciers have retreated on the Antarctic Peninsula and the island of South Georgia.

By plotting the position of glacier ice fronts from old aerial photographs and comparing them with satellite images — a task that took her two painstaking years — Alison Cook found 212 of the Peninsula’s 244 marine glaciers have retreated over the past 50 years and that rates of retreat are increasing. “Very little was understood about the glaciers — people didn’t even know how many there were — so this time-series of coastlines will help us to understand recent changes for the first time,” she explains.

Similar research done on South Georgia has further, very practical benefits. A project published in 2010 found that 97% of glaciers had retreated in the observation period. The retreat of glaciers meant that the risk of invasive rats spreading on the island was increased and the team then supported a project that eradicated rats from the island.