British chart datum to transfer to WGS

The United Kingdom Hydrographic Office has begun its transition from horizontal datum to geoid datum in an attempt to comply with World Geodetic System 1984. The three-year project will result in completely new measurements and printing of charts of Great Britain, The Republic of Ireland, and the Channel Islands.

The new charts will allow GPS users to more accurately plot positions on Admiralty charts, since the new datum is native to GPS. Areas to be completed by June 2000 include the River Clyde; the east coast of England from Great Yarmouth to Harwich; the Solent; and the area of the Irish Sea north and east of the Isle of Man. The east and south coasts of England from Wash to Plymouth, together with the approaches to Liverpool, should be completed in time for the 2000 sailing season.

The U.S.’s North American Datum (NAD) 83, which is the North American component of WGS 1984, was completed in 1983. Updated charts of North America using this system of measurement were completed in the late 1980s.

By Ocean Navigator