South Korea, 18 October 2006 – The South Korean Government yesterday designated Ullung Island as the starting point of a new geodetic system prior to changing to the World Geodetic System (WGS-84). To date the Tokyo Datum has been used for measuring distances after Japan occupied the peninsula in 1910.
The geodetic system is a means of measuring the distance and location of objects on land by using a specific starting point. The starting point of the previous system was Tokyo.
“In the previous system, the farther the measured object was located from the starting point of Tokyo, the bigger errors we had. So we decided to use the international WGS-84 standard and set up the starting point on Ullung Island,” said an official at the Ministry of Government Administration and Home Affairs.
The Tokyo Datum was decided through Japan’s astronomical observations, but the WGS-84, uses the global positioning system (GPS) linked to satellites and is widely used in advanced countries.
Under the new geodetic system, the coordinates of the Ullung Island starting point will be changed from 37 degrees 28 minutes 47.2005 seconds latitude north and 130 degrees 54 minutes 1.1705 seconds longitude east to 37 degrees 28 minutes 57.4331 seconds latitude north and 130 degrees 54 minutes 2.7496 seconds longitude east. The difference in measurements from the Tokyo Datum and those from the WGS-84 is 365 meters southwestward.