The changing map of Antarctica

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The changing map of Antarctica

Scott Island and the adjacent 60 m high Haggitts Pillar. (Photo: John Mitchell, NIWA)

The seas of Antarctica are amongst the most inhospitable in the world, so it is not too surprising that historically their mapping has left a lot to be desired.

That is changing, however, as NIWA’s research vessel Tangaroa carries scientists to Antarctica to survey islands and map the seabed. After three trips, one outcome has been a number of changes to nautical charts.

A 2004 survey resulted in the erasure of Gertrude Rock from NZ nautical chart 14906, as the islet had disappeared from the Ross Sea. Then in 2006, a 48-day voyage to the Ross Sea mapped the exact position of Scott Island (at 67o 22.7’S 179o 54.7’W) for the first time. Scott Island was discovered by William Colbeck in 1902 as his ship Morning steamed south to rescue Scott’s 1901–04 ice-bound Discovery expedition. The island is a mere 370 m long, 180 m wide, and 50 m high, and it was found to be 2.3 km north of its charted position.

Voyage leader, NIWA’s John Mitchell, says it was no real surprise to find that Scott Island was in the wrong place. “Every island we have surveyed during previous voyages to the Antarctic has been significantly out of position – at times by up to 5 or 6 kilometres,” says John. “For much of the year the area is shrouded in snow and fog, so it is important for all shipping that we get the positions right.”

The work was commissioned by Land Information New Zealand.

Research subject: Coasts