Digital mapping leads to discovery of 7,000 new islands in Japan

Tokyo, Japan, Feb 19 — Japan is regularly subjected to volcanic activity and extreme weather; from typhoons to earthquakes, the country experiences it all. Therefore, it could not have been easy to accurately keep count of the number of islands scattered around an area of more than 370,000 square kilometers.

While Japan has seen the formation of new islands and the quiet disappearance of others, geographers have said official statistics showing a composition of around 6,000 islands is way off the mark.

Using the latest in digital mapping technology, geographers are confident that Japan’s island count is now double that of the previously recognized number.

In the first survey of its kind in 35 years, the Geospatial Information Authority of Japan (GSI) now has a total of 14,125 islands as Japanese territory – 7,273 more than previously thought.

However, the government body, which is due to release its findings soon, said the new information was unlikely to change the size of Japan’s territory or territorial waters, according to the Kyodo news agency.

The Geospatial Information Authority of Japan undertook the new study following criticism that the previous data were out of date, meaning the actual number of islands could be vastly higher.

In the last survey, released in 1987 by the coast guard, paper maps were used to tally islands – defined as land masses with a circumference of at least 100 meters – resulting in the previously accepted figure of 6,852.

In the most recent study, officials relied on the same size criterion, but counted islands using digitized maps and cross-referenced the information with past aerial photographs and other data to exclude artificially reclaimed land.

Some of Japan’s 47 prefectures comprise huge numbers of islands. The northern prefecture of Hokkaido – one of the four main islands, along with Honshu, Shikoku, and Kyushu – has 1,473, according to the new survey, while Nagasaki in the southwest has 1,479.

NMT